Determination method of titanium concentrate acid leaching reaction endpoint and preparation method of artificial rutile

Abstract

The invention provides a method for judging an acid leaching reaction endpoint of titanium concentrate and a preparation method of artificial rutile. Aiming at a currently used hydrochloric acid system reaction device (pressurized reaction kettle), the surface heat dissipation of the pressurized reaction kettle is calculated through the Heireng, and then the accuracy of theoretical calculation is verified on site, and corresponding correction is made; then supplementing surface heat dissipation of the reaction kettle through a heating device (steam / electric heating), and keeping a reaction kettle system as a constant-temperature system; along with the reaction of the titanium concentrate and hydrochloric acid in the reaction kettle, the heat of the system is gathered and the temperature rises, and along with the reaction, the reaction intensity is reduced, the reaction difficulty is increased, the reaction speed is slowed down and the temperature rise speed is slowed down until the reaction reaches the end point, the reaction is not carried out any more, the temperature of the system is not increased any more and the temperature is constant. When the temperature in the reaction kettle is constant, the reaction endpoint of the titanium concentrate and hydrochloric acid is obtained. The determination method can accurately determine the end point of the acid leaching reaction, improve the production efficiency and reduce the production cost.

Description

Technical Field

[0001] The invention relates to the field of chemical industry, and in particular to a method for determining the end point of an acid leaching reaction of titanium concentrate, and a method for preparing artificial rutile. Background Art

[0002] Panzhihua is rich in titanium resources, and its proven reserves account for more than 90% of the country's total. Panzhihua titanium concentrate is a typical ilmenite ore with good acid solubility, and is widely used in the production of titanium dioxide by sulfuric acid method; however, the product grade is low, and the impurity content is high, especially the impurities such as calcium and magnesium. After smelting in electric furnace, the CaO+MgO content in the acid-soluble titanium slag is as high as 7% to 11%, and it cannot be directly used in the production of titanium dioxide and titanium metal by boiling chlorination method.

[0003] With the current huge environmental pressure and increasing product competition, the production capacity of titanium dioxide sulfate has gradually decreased, and the production capacity of titanium dioxide chloride has gradually increased. Developed countries basically use the production technology of titanium dioxide chloride. In recent years, my country has also vigorously promoted the upgrading of the titanium dioxide industry and encouraged the development of titanium dioxide chloride. The boiling chloride titanium dioxide technology has developed rapidly. In 2023, the production capacity of titanium dioxide chloride has reached nearly 1000kt / a, and the production capacity under construction or in preparation will reach 1500kt / a. Coupled with the increase in the production capacity of titanium metal, the demand for high-quality titanium raw materials will increase significantly, and there may be a shortage of supply.

[0004] At present, the high-quality raw materials used in the production of chloride titanium dioxide in my country mainly come from two sources: one is imported high-quality ilmenite sand ore (low calcium and magnesium) smelted in an electric furnace to obtain TiO2 grade 90% or 92%, low calcium and magnesium, high titanium slag; the other is directly imported high-quality titanium-rich raw materials (natural rutile, artificial rutile and upgraded titanium slag) with qualified indicators. Therefore, high-quality titanium raw materials mainly rely on foreign imports, and being restricted by others in raw materials will affect the high-end development of my country's titanium industry.

[0005] Major domestic research institutes and universities have conducted a lot of research on titanium resources in Panzhihua. Because the grade of Panzhihua titanium concentrate is low and the content of non-ferrous impurities such as calcium and magnesium is high, the titanium slag obtained after electric furnace smelting is of low grade and cannot be directly used as the raw material of boiling chloride titanium dioxide. After a lot of research, it is shown that the acid leaching process for preparing artificial rutile is one of the effective processes for preparing high-quality titanium raw materials from Panzhihua titanium concentrate with industrial prospects. The acid leaching method for preparing artificial rutile is that dilute hydrochloric acid reacts with impurity elements such as FeO, MgO, CaO, MnO, Al2O3 in titanium concentrate to generate soluble salts that enter the liquid phase, and TiO2 is enriched in the solid phase to obtain high-quality titanium-rich materials. However, the reaction must be carried out in a closed reactor and maintained under certain temperature and pressure conditions to obtain qualified products. Since the reaction is carried out in a closed reactor, it has poor intuitiveness and is difficult to judge the reaction endpoint. If the reaction is stopped before it is complete, it will seriously affect the quality and value of the titanium-rich material product. Therefore, it is usually necessary to extend the reaction time to ensure product quality, which not only causes energy waste, but also affects the production rhythm, resulting in low equipment operating rate, increased production costs, and poor economic efficiency of the entire process. Summary of the invention

[0006] In view of this, the present invention provides a method for determining the end point of the acid leaching reaction of titanium concentrate, and a method for preparing artificial rutile. The method for determining the end point of the acid leaching reaction of titanium concentrate provided by the present invention can accurately determine the end point of the acid leaching reaction, improve production efficiency, and reduce production costs.

[0007] The present invention provides a method for determining the end point of an acid leaching reaction of titanium concentrate, comprising the following steps:

[0008] A) Determine the amount of steam required to maintain heat balance in the reaction equipment at the reaction temperature:

[0009] A1) Theoretically calculate the heat dissipation per unit time Q of the reaction equipment;

[0010] A2) Place the simulated sample and acid solution into the reaction equipment, detect the system temperature T0, introduce steam to heat to the target temperature T1, and control the steam introduction amount to the theoretically required steam amount m L1 , verifying whether the system can maintain heat balance; wherein no reaction occurs between the simulated sample and the acid solution;

[0011] If the system can maintain heat balance, the theoretically required steam volume m L1 That is, the actual amount of steam m required for the reaction equipment to maintain the heat balance of the system at the above target temperature T1 is determined S1 ;

[0012] If the system cannot maintain heat balance, specifically, if temperature drops, the steam volume is increased, and if temperature rises, the steam volume is reduced until the system maintains heat balance. At this time, the corresponding steam volume is determined as the actual steam volume m required for the reaction equipment to maintain the heat balance of the system at the above target temperature T1. S1 ;

[0013] in,

[0014] Theoretically required steam volume m L1 Calculated by formula (2):

[0015] m L1 =Q / C×(T1–T0) Formula (2);

[0016] In formula (2):

[0017] m L1 The theoretical amount of steam required to maintain the heat balance of the system at the target temperature T1, kg / s;

[0018] Q is the heat dissipation per unit time of the reaction equipment obtained in step A1), J / s;

[0019] C is the specific heat capacity of steam at the target temperature T2, J / (kg·K);

[0020] T0 is the system temperature before steam heating, K;

[0021] T1 is the target temperature after steam heating, K;

[0022] A3) Select several temperature points from the reaction temperature range of the titanium concentrate acid leaching reaction as the target temperature T x Repeat step A2) to determine each target temperature T x The actual amount of steam required to maintain the heat balance of the system m Sx ;

[0023] A4) using the temperature T1 in step A2) and the temperature T2 in step A3) x The horizontal axis is the actual steam quantity m required to maintain the heat balance of the system at temperature T1 in step A2). S1 and step A3) temperature T x The actual amount of steam required to maintain the heat balance of the system m Sx As the ordinate, establish a standard curve;

[0024] B) adding titanium concentrate and acid solution to the reaction equipment, introducing steam to heat the system for acid leaching reaction, controlling the steam amount to the actual steam amount required to maintain the heat balance of the system corresponding to the target temperature set for the reaction equipment, and maintaining the heat balance of the reaction equipment; as the acid leaching reaction proceeds, when the temperature of the reaction equipment no longer rises but remains stable, it is determined to be the end point of the acid leaching reaction.

[0025] The present invention also provides a method for determining the end point of the acid leaching reaction of titanium concentrate, comprising the following steps:

[0026] A") Determine the electric heating power required for the reaction equipment to maintain heat balance at the reaction temperature:

[0027] A1) Theoretical calculation of the heat dissipation per unit time Q of the reaction equipment:

[0028] A2″) Place the simulated sample and the acid solution into the reaction equipment, detect the system temperature T0, and heat it to the target temperature T1 by power, and control the electric heating power to be the theoretical required electric heating power P L1 , verifying whether the system can maintain heat balance; wherein no reaction occurs between the simulated sample and the acid solution;

[0029] If the system can maintain heat balance, the theoretical required electric heating power P L1 That is, the actual required electric heating power P of the reaction equipment to maintain the heat balance of the system at the above target temperature T1 is determined. s1 ;

[0030] If the system cannot maintain heat balance, specifically, if temperature drops, the electric heating power is increased, and if temperature rises, the electric heating power is reduced until the system maintains heat balance. At this time, the corresponding electric heating power is determined as the actual electric heating power P required for the reaction equipment to maintain the heat balance of the system at the above target temperature T1. S1 ;

[0031] in,

[0032] Theoretical required electric heating power P L1 Calculated by formula (2):

[0033] P L1 =Q formula (2″);

[0034] In formula (2″):

[0035] P L1 The theoretical electric heating power required to maintain the thermal balance of the system at the target temperature T1, W;

[0036] Q is the heat dissipation per unit time of the reaction equipment obtained in step A1), W;

[0037] A3″) Select several temperature points from the reaction temperature range of the titanium concentrate acid leaching reaction as the target temperature T x Repeat step A2) to determine each target temperature T x The actual electric heating power P required to maintain the thermal balance of the system Sx ;

[0038] A4″) with the temperature T1 in step A2) and the several temperatures T in step A3) x = is the horizontal axis, and the actual electric heating power P required to maintain the thermal balance of the system at temperature T1 in step A2) is s1 and step A3) temperature T x The actual electric heating power P required to maintain the thermal balance of the system Sx As the ordinate, establish a standard curve;

[0039] B") adding titanium concentrate and acid solution into the reaction equipment, applying power to heat the system for acid leaching reaction, controlling the electric heating power to the actual electric heating power required to maintain the heat balance of the system corresponding to the target temperature set for the reaction equipment, and maintaining the heat balance of the reaction equipment; as the acid leaching reaction proceeds, when the temperature of the reaction equipment no longer rises but remains stable, it is determined to be the end point of the acid leaching reaction.

[0040] Preferably, in step A2), the simulation sample is quartz sand; and the acid solution is hydrochloric acid.

[0041] Preferably, in step A2):

[0042] The operation mode of heating the target temperature T1 by introducing steam is as follows: firstly introduce excess steam into the heating system, and when the target temperature T1 is approached, reduce the amount of steam introduced to the theoretically required amount of steam m L1 , continue heating to the target temperature T1;

[0043] The criterion for judging whether the system maintains thermal balance is that the system temperature fluctuates to 0°C within a period of ≥30 minutes.

[0044] Preferably, the total number of temperature points selected in steps A2)-A3) is ≥5;

[0045] The step length between the selected temperature points is 5 to 15°C.

[0046] Preferably, in step A2″), the simulation sample is quartz sand; and the acid solution is hydrochloric acid.

[0047] Preferably, in step A2″):

[0048] The operation mode of heating to the target temperature T1 is: firstly, the heating system is heated at a high power, and when the target temperature T1 is approached, the electric heating power is reduced to the theoretical required electric heating power P L1 , continue heating to the target temperature T1;

[0049] The criterion for judging whether the system maintains thermal balance is that the system temperature fluctuates to 0°C within a period of ≥30 minutes.

[0050] Preferably, the total number of temperature points selected in steps A2″)-A3″) is ≥5;

[0051] The step length between the selected temperature points is 5 to 15°C.

[0052] Preferably, the temperature close to the target temperature T1 is 15-30° C. lower than the target temperature T1.

[0053] The present invention also provides a method for preparing artificial rutile, comprising:

[0054] Add titanium concentrate and acid solution to the reaction equipment, heat the system to carry out acid leaching reaction, and when it is determined that the acid leaching reaction reaches the end point, cut off the heat source, cool down the material, and perform post-processing to obtain an artificial rutile product;

[0055] Wherein, the method for determining whether the acid leaching reaction has reached the endpoint is the determination method described in the above technical solution.

[0056] In the prior art, many patents have been applied for the preparation of artificial rutile by hydrochloric acid leaching of Panxi titanium concentrate, but none of them involve the determination of the end point of the leaching reaction. Panzhihua Iron and Steel uses a pressurized reactor to prepare artificial rutile by hydrochloric acid pressure leaching of self-produced ultrafine titanium concentrate, which is heated by steam and controls the termination of the reaction by controlling the reaction time after reaching the reaction temperature. Due to the uncertainty of the reaction end point (i.e., it is uncertain when the reaction stops), in order to ensure that the reaction is fully carried out and the product quality is high, the extended process time mode is usually adopted, but this will cause the production rhythm to slow down, the equipment utilization rate to decrease, the energy consumption to increase, and the production cost of artificial rutile to increase. The adverse effects. That is, the prior art has not paid attention to determining the end point of the leaching reaction and terminating the reaction in time at the end point of the reaction, but has adopted a method of extending the process time to ensure that the reaction end point is exceeded.

[0057] The technical route of the present invention is as follows: (1) for the hydrochloric acid system reaction device (pressurized reactor) currently used, the heat dissipation of the surface of the pressurized reactor is calculated by theory, and then the accuracy of the theoretical calculation is verified on site, and corresponding corrections are made; (2) the heat dissipation of the surface of the reactor is supplemented by a heating device (steam / electric heating) to keep the reactor system as a constant temperature system; (3) as the reaction of titanium concentrate and hydrochloric acid in the reactor proceeds, the heat of the system accumulates and the temperature rises. As the reaction proceeds, the intensity of the reaction decreases, the difficulty increases, the reaction speed slows down, and the heating speed slows down until the reaction reaches the end point, the reaction no longer proceeds, the system temperature no longer increases, and the temperature is constant. That is, when the temperature in the reactor is constant, it is the end point of the reaction of titanium concentrate and hydrochloric acid.

[0058] The present invention determines the reaction endpoint by tracking the manifestation of the reaction exothermic situation in the reactor, that is, the reaction endpoint is determined by the temperature change of the reaction system, thereby achieving accurate control; thereby greatly shortening the process time and reducing energy consumption, improving production efficiency and reducing production costs. DETAILED DESCRIPTION

[0059] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0060] In this article, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0061] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0062] Herein, when it comes to numerical ranges, unless otherwise specified, the numerical ranges are deemed to be continuous and include the minimum and maximum values ​​of the range, as well as every value between such minimum and maximum values. Further, when a range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges included therein.

[0063] In this article, when referring to the unit of a data range, if there is a unit only after the right endpoint, it means that the units of the left and right endpoints are the same. For example, 115-165℃ means that the units of the left endpoint "115" and the right endpoint "165" are both ℃.

[0064] The present invention provides a method for determining the end point of an acid leaching reaction of titanium concentrate, comprising the following steps:

[0065] A) Determine the amount of steam required to maintain heat balance in the reaction equipment at the reaction temperature:

[0066] A1) Theoretically calculate the heat dissipation per unit time Q of the reaction equipment;

[0067] A2) Place the simulated sample and acid solution into the reaction equipment, detect the system temperature T0, introduce steam to heat to the target temperature T1, and control the steam introduction amount to the theoretically required steam amount m L1 , verifying whether the system can maintain heat balance; wherein no reaction occurs between the simulated sample and the acid solution;

[0068] If the system can maintain heat balance, the theoretically required steam volume m L1 That is, the actual amount of steam m required for the reaction equipment to maintain the heat balance of the system at the above target temperature T1 is determined S1 ;

[0069] If the system cannot maintain heat balance, specifically, if temperature drops, the steam volume is increased, and if temperature rises, the steam volume is reduced until the system maintains heat balance. At this time, the corresponding steam volume is determined as the actual steam volume m required for the reaction equipment to maintain the heat balance of the system at the above target temperature T1. S1 ;

[0070] in,

[0071] Theoretically required steam volume m L1 Calculated by formula (2):

[0072] m L1 =Q / C×(T1–T0) Formula (2);

[0073] In formula (2):

[0074] m L1 The theoretical amount of steam required to maintain the heat balance of the system at the target temperature T1, kg / s;

[0075] Q is the heat dissipation per unit time of the reaction equipment obtained in step A1), J / s;

[0076] C is the specific heat capacity of steam at the target temperature T2, J / (kg·K);

[0077] T0 is the system temperature before steam heating, K;

[0078] T1 is the target temperature after steam heating, K;

[0079] A3) Select several temperature points from the reaction temperature range of the titanium concentrate acid leaching reaction as the target temperature T x Repeat step A2) to determine each target temperature T x The actual amount of steam required to maintain the heat balance of the system m Sx ;

[0080] A4) using the temperature T1 in step A2) and the temperature T2 in step A3) x The horizontal axis is the actual steam quantity m required to maintain the heat balance of the system at temperature T1 in step A2). S1 and step A3) temperature T x The actual amount of steam required to maintain the heat balance of the system m Sx As the ordinate, establish a standard curve;

[0081] B) adding titanium concentrate and acid solution to the reaction equipment, introducing steam to heat the system for acid leaching reaction, controlling the steam amount to the actual steam amount required to maintain the heat balance of the system corresponding to the target temperature set for the reaction equipment, and maintaining the heat balance of the reaction equipment; as the acid leaching reaction proceeds, when the temperature of the reaction equipment no longer rises but remains stable, it is determined to be the end point of the acid leaching reaction.

[0082] In view of the current problem that the endpoint of preparing artificial rutile by hydrochloric acid pressure leaching of Panxi titanium concentrate is difficult to judge and difficult to accurately control, the applicant has deeply analyzed the material characteristics of titanium concentrate and the liquid-solid reaction mechanism of hydrochloric acid leaching, and found that the reaction of impurity elements FeO, MgO, CaO, MnO, Al2O3, etc. in titanium concentrate with hydrochloric acid is an exothermic reaction. If the thermal balance in the reaction system is maintained, the reaction endpoint can be accurately and timely judged by temperature changes. Therefore, the present invention judges the reaction endpoint by tracking the manifestation of the reaction exothermic situation in the reactor, that is, judging the reaction endpoint by the temperature change of the reaction system, thereby achieving accurate control.

[0083] [About Step A]:

[0084] A) Determine the amount of steam required to maintain heat balance in the reaction equipment at the reaction temperature.

[0085] About step A1) : Theoretically calculate the heat dissipation Q per unit time of the reaction equipment.

[0086] In the present invention, the reaction equipment is preferably a reactor, specifically a pressurized reactor, which is a common reaction device in the current titanium concentrate acid leaching system. During the titanium concentrate acid leaching reaction process, the reactor itself will dissipate heat. The present invention pre-theoretically calculates the surface heat dissipation of the reactor.

[0087] The present invention has no special restrictions on the theoretical calculation of the heat dissipation Q per unit time of the reaction equipment, and it can be calculated according to methods known in the art. For example, the heat dissipation Q of the reaction equipment can be calculated based on the surface area of ​​the reaction equipment, the convective heat transfer coefficient of the reaction equipment, the temperature of the reaction system, etc. Specifically, the heat dissipation Q per unit time of the reaction equipment can be theoretically calculated by formula (1):

[0088] Q = h × A × (Ts-Ta) Formula (1);

[0089] In formula (1):

[0090] Q is the heat dissipation per unit time of the reaction equipment, W (1W = 1J / s);

[0091] h is the convective heat transfer coefficient of the reaction equipment, W / (m 2 K);

[0092] A is the effective heat dissipation area of ​​the reaction equipment surface, m 2 ;

[0093] Ts is the surface temperature of the reaction equipment, K;

[0094] Ta is the ambient temperature, K.

[0095] In the present invention, when there are multiple options for the units corresponding to the parameters in the above formula (1), various unit forms can be used as long as all parameters are unified. For example, the temperature unit can be ℃ or K. If the temperature unit in the unit of parameter h is K, the units of parameters Ts and Ta can also be unified to K. This is only an adaptive change in the unit form, and the essence of the scheme has not changed, and it also belongs to the protection scope of the present invention. In this article, the same applies to other places and will not be repeated one by one.

[0096] About step A2) :

[0097] A2) placing the simulated sample and the acid solution into the reaction device (wherein the simulated sample and the acid solution do not react), detecting the system temperature T0, introducing steam to heat to the target temperature T1, and controlling the steam introduction amount to be the theoretically required steam amount m L1 , verify whether the system can maintain heat balance; if the system can maintain heat balance, then the theoretical required steam volume m L1 That is, the actual amount of steam m required for the reaction equipment to maintain the heat balance of the system at the above target temperature T1 is determined S1 If the system cannot maintain heat balance, specifically, if the temperature drops, the steam volume is increased, and if the temperature rises, the steam volume is reduced until the system maintains heat balance. At this time, the corresponding steam volume is determined as the actual steam volume m required for the reaction equipment to maintain the heat balance of the system at the above target temperature T1. S1 .

[0098] In the present invention, the simulated sample is a simulated titanium concentrate, but the difference is that the simulated sample cannot react with the acid solution (neither exothermic nor endothermic), and the physical and chemical properties of other aspects (such as solid particles, particle size distribution, bulk density, specific heat capacity, etc.) must be similar to those of the titanium concentrate. In the present invention, the simulated sample is preferably quartz sand.

[0099] In the present invention, the acid solution is preferably hydrochloric acid, more preferably dilute hydrochloric acid. The mass percentage concentration of the dilute hydrochloric acid is preferably 16% to 25%, specifically 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%.

[0100] In the present invention, the dosage relationship between the simulation sample and the acid solution can be implemented according to the dosage relationship between the titanium concentrate and the acid solution during the acid leaching of titanium concentrate in the art.

[0101] In the present invention, the simulated sample and the acid solution are placed in the reaction equipment, and the system temperature T0 is pre-detected before heating, that is, the system temperature before heating is recorded. Then, steam is introduced to heat to the target temperature T1. In the present invention, the target temperature T1 is selected from the reaction temperature of the acid leaching reaction of titanium concentrate in the art. Generally, the reaction temperature of the acid leaching reaction of titanium concentrate is 115-165°C, preferably 125-145°C. The present invention selects any temperature point from the above reaction temperature range as the target temperature this time, and introduces steam to heat to the target reaction temperature.

[0102] In the present invention, the steam is preferably saturated steam.

[0103] In the present invention, there are two operation modes for "introducing steam to heat to the target temperature T1", which are as follows: (1) Mode 1: Introducing the theoretically required steam volume m L1 Continue heating until the target temperature T1. (2) Method 2: First, introduce excess steam to heat the system. When the target temperature T1 is approached, reduce the amount of steam introduced to the theoretical required steam amount m L1 , continue heating to the target temperature T1. In the second method, the excess steam refers to the amount of steam m required by theory. L1Larger steam. The target temperature T1 to be approached is preferably 15-30°C lower than the target temperature T1, that is, 15-30°C lower than the target temperature T1, reaching T1-(15-30)°C, specifically T1-15°C, T1-16°C, T1-17°C, T1-18°C, T1-19°C, T1-20°C, T1-21°C, T1-22°C, T1-23°C, T1-24°C, T1-25°C, T1-26°C, T1-27°C, T1-28°C, T1-29°C, T1-30°C. First, a large amount of steam is introduced to quickly heat up the system so that it approaches the target temperature faster. When it is about to approach the target temperature, the steam amount is reduced and changed to the theoretically required steam amount m L1 , and continue to raise the temperature of the system to the target temperature T1. The present invention preferably adopts the second method, which can save process time and improve process efficiency.

[0104] In the present invention, after steam is introduced and heated to the target temperature T1, the theoretically required steam volume m L1 Continue to introduce steam to maintain the thermal balance of the system.

[0105] In the present invention, the theoretically required steam volume m L1 Calculated by formula (2):

[0106] m L1 =Q / C×(T1-T0) Formula (2);

[0107] In formula (2):

[0108] m L1 The theoretical amount of steam required to maintain the heat balance of the system at the target temperature T1, kg / s;

[0109] Q is the heat dissipation per unit time of the reaction equipment obtained in step A1), J / s;

[0110] C is the specific heat capacity of steam at the target temperature T2, J / (kg·K);

[0111] T0 is the system temperature before steam heating, K;

[0112] T1 is the target temperature after steam heating, K.

[0113] In the present invention, after steam is introduced and heated to the target temperature T1, the theoretically required steam volume m L1Continue to introduce steam to maintain the thermal balance of the system, and verify whether the system can maintain thermal balance after a period of time. In the present invention, the criterion for judging whether the system maintains thermal balance is: the system temperature fluctuates by 0°C within a time period of ≥30 minutes; wherein, the time period of ≥30 minutes refers to continuous monitoring for 30 minutes or longer to see whether the system temperature fluctuates during this period of time. If there is no fluctuation (the fluctuation temperature is 0°C), that is, the system temperature is constant, then the system is deemed to have maintained thermal balance. Among them, the above-mentioned monitoring time period is preferably 30 to 45 minutes, specifically 30 minutes, 35 minutes, 40 minutes, 45 minutes, and more preferably 30 minutes. In the present invention, steam is first introduced to heat the reactor to the target temperature T1. Since the reactor itself will dissipate heat and cause heat loss, the theoretically required steam amount m is added through the supplementary heat system (steam heating). L1 Continue to introduce steam to try to compensate for the heat dissipation and maintain the thermal balance of the system, and then verify whether the theoretically calculated amount of steam can actually maintain the thermal balance of the system.

[0114] The verification results and responses are as follows:

[0115] If the system can maintain heat balance, the theoretically required steam volume m L1 That is, the actual amount of steam m required for the reaction equipment to maintain the heat balance of the system at the above target temperature T1 is determined S1 ; That is, the theoretical amount of steam required m L1 The actual amount of steam required m S1 Equal, no correction required.

[0116] If the system cannot maintain heat balance, specifically, if temperature drops, the steam volume is increased, and if temperature rises, the steam volume is reduced until the system maintains heat balance. At this time, the corresponding steam volume is determined as the actual steam volume m required for the reaction equipment to maintain the heat balance of the system at the above target temperature T1. S1 This situation refers to the theoretically required steam volume m L1 Failure to maintain the thermal balance of the system, therefore increasing or decreasing the steam volume based on it to adjust the theoretical required steam volume m L1 Correction is made until it can maintain the thermal balance of the system. The steam volume at this time is determined as the actual required steam volume m S1 .

[0117] The above is equivalent to calculating the theoretical required steam volume m L1 Finally, a load test is carried out on the reactor to verify whether the theoretical heat dissipation is consistent with the actual situation, and the theoretical calculation results are corrected (if they are inconsistent), so as to obtain the actual steam volume m required to maintain the heat balance of the system at a certain target temperature T1 S1 .

[0118] About step A3) :

[0119] A3) Select several temperature points from the reaction temperature range of the titanium concentrate acid leaching reaction as the target temperature T x Repeat step A2) to determine each target temperature T x The actual amount of steam required to maintain the heat balance of the system m Sx .

[0120] As mentioned above, the reaction temperature range of the titanium concentrate acid leaching reaction is 115-165°C, preferably 125-145°C. In step A2), a temperature point T1 is selected and the actual required steam amount m required to maintain the heat balance of the system at the temperature point T1 is obtained. S1 Step A3) is to select several more temperature points T from the above reaction temperature range. x Repeat the experiment in step A2) to determine the actual steam volume m required to maintain the heat balance of the system at each of the other temperature points. Sx .

[0121] In general, steps A2)-A3) generally select several temperature points from the reaction temperature range of the titanium concentrate acid leaching reaction, and determine the actual amount of steam required to maintain the heat balance of the system at each temperature point.

[0122] In the present invention, the total number of temperature points selected in steps A2)-A3) is preferably ≥5. The step length between the selected temperature points is preferably 5-15°C, specifically 5°C, 10°C, and 15°C. The step length refers to the temperature interval between the temperature points. Taking a step length of 5°C as an example, if the first temperature point is 125°C, the remaining temperature points are 130°C, 135°C, 140°C, 145°C, and ... According to the reaction characteristics of pressure leaching of titanium concentrate, in the present invention, for steps A2)-A3), the five temperature points of 125°C, 130°C, 135°C, 140°C, and 145°C are preferred, and the actual amount of steam required to maintain the heat balance of the system corresponding to the above five temperature points is obtained.

[0123] About step A4) :

[0124] A4) using the temperature T1 in step A2) and the temperature T2 in step A3) x The horizontal axis is the actual steam quantity m required to maintain the heat balance of the system at temperature T1 in step A2). S1 and step A3) temperature T x The actual amount of steam required to maintain the heat balance of the system m Sx Use y as the vertical axis to establish a standard curve.

[0125] In the present invention, step A4) is to establish a standard curve between the temperature points selected in steps A2)-A3) and the actual amount of steam required to maintain the heat balance of the system at each temperature point, so as to obtain the required steam amount for the subsequent actual titanium concentrate acid leaching reaction. For example, assuming that the set temperature of the titanium concentrate acid leaching reaction is T, the actual amount of steam required to maintain the heat balance of the system m is pre-calculated through the standard curve. S In the subsequent actual acid leaching reaction, this amount of steam is introduced to maintain the system balance.

[0126] In the present invention, when drawing the standard curve, the temperature point can also be used as the vertical coordinate, and the steam volume corresponding to the temperature point can be used as the horizontal coordinate. This is only different in form from the drawing method in the previous text. In essence, a standard curve is established between the temperature point and the steam volume, which also falls within the protection scope of the present invention.

[0127] [About step B]:

[0128] B) adding titanium concentrate and acid solution to the reaction equipment, introducing steam to heat the system for acid leaching reaction, controlling the steam amount to the actual steam amount required to maintain the heat balance of the system corresponding to the target temperature set for the reaction equipment, and maintaining the heat balance of the reaction equipment; as the acid leaching reaction proceeds, when the temperature of the reaction equipment no longer rises but remains stable, it is determined to be the end point of the acid leaching reaction.

[0129] In the present invention, the reaction equipment is preferably a reactor, specifically a pressure reactor, which is a common reaction device in the current titanium concentrate acid leaching system, and preferably a reaction equipment of the same specifications as that used in step A).

[0130] In the present invention, the acid solution is preferably hydrochloric acid, more preferably dilute hydrochloric acid. The mass percentage concentration of the dilute hydrochloric acid is preferably 16% to 25%, specifically 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%.

[0131] In the present invention, the dosage relationship of the titanium concentrate and the acid solution is controlled as follows: the liquid-to-solid ratio is (2.8-3.5):1, specifically 2.8:1, 2.9:1, 3.0:1, 3.1:1, 3.2:1, 3.3:1, 3.4:1, 3.5:1, and more preferably 3.0:1. The above liquid-to-solid ratio refers to the mass ratio of liquid to solid. The total volume of the mixed material can be determined according to the filling rate of the reactor.

[0132] In the present invention, the steam is preferably saturated steam.

[0133] In the present invention, the acid leaching reaction process is preferably accompanied by stirring; that is, after adding the materials, the heating reaction process is accompanied by mechanical stirring.

[0134] In the present invention, there are two operating modes for "introducing steam to heat the system for acid leaching reaction", which are as follows: (1) Mode 1: Introducing the actual required amount of steam m sx Heating to the target temperature T x (2) Method 2: First, introduce excess steam into the heating system and wait until the target temperature T is reached. x When the steam input is controlled to be the actual required steam volume m sx , directly reach the target temperature T x In the second method, the excess steam refers to the amount of steam m sx The target temperature T to be approached x Preferably below the target temperature T x 15~30℃, that is, higher than the target temperature T x 15-30℃ lower, reach T x –(15~30)℃, specifically T x –15℃, T x –16℃, T x –17℃, T x –18℃, T x –19℃, T x –20℃, T x –21℃, T x –22℃, T x –23℃, T x –24℃, T x –25℃, T x –26℃, T x –27℃, T x –28℃, T x –29℃, T x –30℃. First, introduce a large amount of steam to quickly heat up the system and make it approach the target temperature faster. When it is close to the target temperature, reduce the steam volume to the actual required steam volume m sx , continue to heat the system to the target temperature T x The present invention preferably adopts the second method, which can save process time and improve process efficiency.

[0135] In the present invention, steam is introduced to heat the mixture to the target temperature T x After that, according to the actual required steam volume m sxContinue to introduce steam to maintain the thermal balance of the system. As the titanium concentrate reacts with hydrochloric acid, the system temperature gradually increases. The reaction speed is faster in the early stage, and the system heats up faster. Maintain a constant amount of steam until the temperature of the reactor no longer rises (that is, the temperature is stable), then it is determined to have reached the end point of the acid leaching reaction. In the present invention, the temperature no longer rises specifically means that the system temperature fluctuates to 0°C within a time period of ≥2min; wherein, the time period of ≥2min refers to continuous monitoring for 2min or longer to see whether the system temperature still rises and fluctuates during this period of time. If it does not rise (the fluctuation temperature is 0°C), that is, the system temperature is constant, then it is considered to have reached the end point of the acid leaching reaction. Among them, the above-mentioned monitoring time period is selected as 2 to 5min, specifically 2min, 3min, 4min, 5min, preferably 3min. When the end point of the acid leaching reaction is reached, the heat source can be cut off, the temperature can be lowered and the material can be discharged to obtain an artificial rutile product.

[0136] The present invention also provides another method for determining the end point of the acid leaching reaction of titanium concentrate, comprising the following steps:

[0137] A") Determine the electric heating power required for the reaction equipment to maintain heat balance at the reaction temperature:

[0138] A1, theoretical calculation of the heat dissipation per unit time Q of the reaction equipment;

[0139] A2″) Place the simulated sample and the acid solution into the reaction equipment, detect the system temperature T0, and heat it to the target temperature T1 by power, and control the electric heating power to be the theoretical required electric heating power P L1 , verifying whether the system can maintain heat balance; wherein no reaction occurs between the simulated sample and the acid solution;

[0140] If the system can maintain heat balance, the theoretical required electric heating power P L1 That is, the actual required electric heating power P of the reaction equipment to maintain the heat balance of the system at the above target temperature T1 is determined. s1 ;

[0141] If the system cannot maintain heat balance, specifically, if temperature drops, the electric heating power is increased, and if temperature rises, the electric heating power is reduced until the system maintains heat balance. At this time, the corresponding electric heating power is determined as the actual electric heating power P required for the reaction equipment to maintain the heat balance of the system at the above target temperature T1. S1 ;

[0142] in,

[0143] Theoretical required electric heating power P L1 Calculated by formula (2):

[0144] P L1 =Q formula (2″);

[0145] In formula (2″):

[0146] P L1 The theoretical electric heating power required to maintain the thermal balance of the system at the target temperature T1, W;

[0147] Q is the heat dissipation per unit time of the reaction equipment obtained in step A1), W;

[0148] A3″) Select several temperature points from the reaction temperature range of the titanium concentrate acid leaching reaction as the target temperature T x Repeat step A2) to determine each target temperature T x The actual electric heating power P required to maintain the thermal balance of the system Sx ;

[0149] A4″) with the temperature T1 in step A2) and the several temperatures T in step A3) x = is the horizontal axis, and the actual electric heating power P required to maintain the thermal balance of the system at temperature T1 in step A2) is s1 and step A3) temperature T x The actual electric heating power P required to maintain the thermal balance of the system Sx As the ordinate, establish a standard curve;

[0150] B") adding titanium concentrate and acid solution into the reaction equipment, applying power to heat the system for acid leaching reaction, controlling the electric heating power to the actual electric heating power required to maintain the heat balance of the system corresponding to the target temperature set for the reaction equipment, and maintaining the heat balance of the reaction equipment; as the acid leaching reaction proceeds, when the temperature of the reaction equipment no longer rises but remains stable, it is determined to be the end point of the acid leaching reaction.

[0151] [Regarding Step A']:

[0152] A") Determine the electrical heating power required for the reaction equipment to maintain heat balance at the reaction temperature.

[0153] About step A1) : Theoretically calculate the heat dissipation Q per unit time of the reaction equipment.

[0154] This step is the same as the first step in the first method for determining the endpoint of the acid leaching reaction of titanium concentrate (recorded as technical solution 1) mentioned above, and will not be described in detail here.

[0155] Regarding step A2) :

[0156] A2″) put the simulated sample and the acid solution into the reaction device (wherein the simulated sample and the acid solution do not react), detect the system temperature T0, and heat it to the target temperature T1, and control the electric heating power to be the theoretical required electric heating power PL1 , verify whether the system can maintain heat balance; if the system can maintain heat balance, then the theoretical required electric heating power P L1 That is, the actual required electric heating power P of the reaction equipment to maintain the heat balance of the system at the above target temperature T1 is determined. s1 If the system cannot maintain heat balance, specifically, if temperature drops, the electric heating power is increased, and if temperature rises, the electric heating power is reduced until the system maintains heat balance. At this time, the corresponding electric heating power is determined as the actual electric heating power P required for the reaction equipment to maintain the heat balance of the system at the above target temperature T1. S1 .

[0157] In the present invention, the types and dosages of the simulated sample and acid solution are consistent with those in the above technical solution 1, and will not be described in detail here.

[0158] In the present invention, the simulated sample and the acid solution are placed in the reaction equipment, and the system temperature T0 is pre-detected before heating, that is, the system temperature before heating is recorded. Then, the system is powered on and heated to the target temperature T1. In the present invention, the target temperature T1 is selected from the reaction temperature of the acid leaching reaction of titanium concentrate in the art. Generally, the reaction temperature of the acid leaching reaction of titanium concentrate is 115-165°C, preferably 125-145°C. The present invention selects any temperature point from the above reaction temperature range as the target temperature this time, and powers on and heats to the target reaction temperature.

[0159] In the present invention, the acid leaching reaction process is preferably accompanied by stirring; that is, after adding the materials, the heating reaction process is accompanied by mechanical stirring.

[0160] In the present invention, there are two operation modes for "heating to target temperature T1", which are as follows: (1) Mode 1: According to the theoretical required electric heating power P L1 Continue heating until the target temperature T1. (2) Method 2: First, turn on the heating system at high power, and when it approaches the target temperature T1, reduce the electric heating power to the theoretical required electric heating power P L1 , and continue heating to the target temperature T1. In the second method, the high-power heating system first refers to the use of a higher than theoretically required electric heating power P L1Greater electric heating power. The target temperature T1 to be approached is preferably 15-30°C lower than the target temperature T1, that is, 15-30°C lower than the target temperature T1, reaching T1-(15-30)°C, specifically T1-15°C, T1-16°C, T1-17°C, T1-18°C, T1-19°C, T1-20°C, T1-21°C, T1-22°C, T1-23°C, T1-24°C, T1-25°C, T1-26°C, T1-27°C, T1-28°C, T1-29°C, T1-30°C. First, high power is turned on to quickly heat up the system so that it approaches the target temperature faster. When it is about to approach the target temperature, the electric heating power is reduced and changed to the theoretically required electric heating power P. L1 , and continue to raise the temperature of the system to the target temperature T1. The present invention preferably adopts the second method, which can save process time and improve process efficiency.

[0161] In the present invention, after heating to the target temperature T1, the electric heating power P required in theory is L1 Continue to power on the heater to maintain the thermal balance of the system.

[0162] In the present invention, the theoretical required electric heating power P L1 Calculated by formula (2):

[0163] P L1 =Q formula (2″);

[0164] In formula (2″):

[0165] P L1 The theoretical electric heating power required to maintain the thermal balance of the system at the target temperature T1, W;

[0166] Q is the heat dissipation per unit time of the reaction equipment obtained in step A1), W.

[0167] In the present invention, after the electric heating reaches the target temperature T1, the electric heating power P required in theory is L1 Continue to heat the system to maintain thermal balance, and verify after a period of time whether the system can maintain thermal balance. In the present invention, the criterion for judging whether the system maintains thermal balance is: the system temperature fluctuates to 0°C within a time period of ≥30 minutes; wherein, the time period of ≥30 minutes refers to continuous monitoring for 30 minutes or longer to see whether the system temperature fluctuates during this period of time. If there is no fluctuation (fluctuation temperature is 0°C), that is, the system temperature is constant, then the system is deemed to maintain thermal balance. wherein, the above-mentioned monitoring time period is preferably 30 to 45 minutes, specifically 30 minutes, 35 minutes, 40 minutes, 45 minutes, and more preferably 30 minutes.

[0168] The verification results and responses are as follows:

[0169] If the system can maintain heat balance, the theoretical required electric heating power P L1 That is, the actual required electric heating power P of the reaction equipment to maintain the heat balance of the system at the above target temperature T1 is determined. s1 . That is, the theoretical required electric heating power P L1 The actual required electric heating power P s1 Equal, no correction required.

[0170] If the system cannot maintain heat balance, specifically, if temperature drops, the electric heating power is increased, and if temperature rises, the electric heating power is reduced until the system maintains heat balance. At this time, the corresponding electric heating power is determined as the actual electric heating power P required for the reaction equipment to maintain the heat balance of the system at the above target temperature T1. S1 This situation refers to the theoretical required electric heating power P L1 The system thermal balance cannot be maintained, so the electric heating power is increased or decreased based on it to adjust the theoretical required electric heating power P L1 Correction is performed until it can maintain the thermal balance of the system. The electric heating power at this time is determined as the actual required electric heating power P s1 .

[0171] Regarding step A3) :

[0172] A3″) Select several temperature points from the reaction temperature range of the titanium concentrate acid leaching reaction as the target temperature T x Repeat step A2) to determine each target temperature T x The actual electric heating power P required to maintain the thermal balance of the system Sx .

[0173] Similar to the above technical solution 1, the reaction temperature range of the titanium concentrate acid leaching reaction is 115-165°C, preferably 125-145°C. Step A2″) has selected a temperature point T1 and obtained the actual required electric heating power P required to maintain the heat balance of the system at the temperature point T1. s1 Step A3) is to select several more temperature points T from the above reaction temperature range. x Repeat the experiment according to step A2″) to determine the actual required electric heating power P required to maintain the heat balance of the system corresponding to the several temperature points respectively. sx .

[0174] In general, similar to the above technical solution 1, steps A2″)-A3″) generally select several temperature points from the reaction temperature range of the titanium concentrate acid leaching reaction, and determine the actual required electric heating power P corresponding to each temperature point to maintain the heat balance of the system. sx .

[0175] In the present invention, the total number of temperature points selected in steps A2")-A3") is preferably ≥5. The step length between the selected temperature points is preferably 5-15°C, specifically 5°C, 10°C, and 15°C. According to the characteristics of the pressure leaching reaction of titanium concentrate, in the present invention, for steps A2")-A3"), the five temperature points of 125°C, 130°C, 135°C, 140°C, and 145°C are preferred, and the actual required electric heating power P corresponding to the above five temperature points to maintain the heat balance of the system is obtained. sx .

[0176] Regarding step A4) :

[0177] A4″) with the temperature T1 in step A2) and the several temperatures T in step A3) x = is the horizontal axis, and the actual electric heating power P required to maintain the thermal balance of the system at temperature T1 in step A2) is s1 and step A3) temperature T x The actual electric heating power P required to maintain the thermal balance of the system Sx Use y as the vertical axis to establish a standard curve.

[0178] Similar to the above technical solution 1, step A4″) is to compare the temperature points selected in steps A2″)-A3″) with the actual electric heating power P required to maintain the heat balance of the system at each temperature point. sx A standard curve is established between the two, so as to obtain the required electric heating power for subsequent actual titanium concentrate acid leaching reaction. For example, assuming that the set temperature of the titanium concentrate acid leaching reaction is T, the actual required electric heating power m required to maintain the heat balance of the system can be calculated in advance through the standard curve. S In the subsequent actual acid leaching reaction, the electric heating power is used to maintain the system balance.

[0179] In the present invention, when drawing the standard curve, the temperature point can also be the vertical coordinate, and the electric heating power corresponding to the temperature point can be the horizontal coordinate. This is only different in form from the drawing method in the previous text. In essence, a standard curve is established between the temperature point and the electric heating power, which also falls within the protection scope of the present invention.

[0180] [Regarding Step B']:

[0181] B") adding titanium concentrate and acid solution into the reaction equipment, applying power to heat the system for acid leaching reaction, controlling the electric heating power to the actual electric heating power required to maintain the heat balance of the system corresponding to the target temperature set for the reaction equipment, and maintaining the heat balance of the reaction equipment; as the acid leaching reaction proceeds, when the temperature of the reaction equipment no longer rises but remains stable, it is determined to be the end point of the acid leaching reaction.

[0182] In the present invention, the reaction equipment is preferably a reactor, specifically a pressure reactor, which is a common reaction device in the current titanium concentrate acid leaching system, and preferably a reaction equipment of the same specifications as that used in step A).

[0183] In the present invention, the acid solution is preferably hydrochloric acid, more preferably dilute hydrochloric acid. The mass percentage concentration of the dilute hydrochloric acid is preferably 16% to 25%, specifically 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%.

[0184] In the present invention, the dosage relationship of the titanium concentrate and the acid solution is controlled as follows: the liquid-to-solid ratio is (2.8-3.5):1, specifically 2.8:1, 2.9:1, 3.0:1, 3.1:1, 3.2:1, 3.3:1, 3.4:1, 3.5:1, and more preferably 3.0:1. The above liquid-to-solid ratio refers to the mass ratio of liquid to solid. The total volume of the mixed material can be determined according to the filling rate of the reactor.

[0185] In the present invention, there are two operating modes for "applying electricity to heat the system for acid leaching reaction", which are as follows: (1) Mode 1: using the actual required electric heating power P Sx Heating to the target temperature T x (2) Method 2: First, turn on the heating system at high power and wait until it approaches the target temperature T x When the electric heating power is reduced to the actual required electric heating power P Sx , directly reach the target temperature T x In the second method, the high-power heating system refers to the use of a higher power than the actual required electric heating power P Sx The target temperature T to be approached x Preferably below the target temperature T x 15~30℃, that is, higher than the target temperature T x 15-30℃ lower, reach T x –(15~30)℃, specifically T x –15℃, T x –16℃, T x –17℃, T x –18℃, T x –19℃, T x –20℃, T x –21℃, T x –22℃, T x –23℃, T x –24℃, T x –25℃, T x –26℃, T x –27℃, T x –28℃, T x–29℃, T x –30℃. First, high power is applied to quickly heat up the system, so that it approaches the target temperature faster. When it is close to the target temperature, the electric heating power is reduced to the actual required electric heating power P Sx , continue to heat the system to the target temperature T x The present invention preferably adopts the second method, which can save process time and improve process efficiency.

[0186] In the present invention, heating to the target temperature T x After that, according to the actual required electric heating power P Sx Continue heating to maintain the thermal balance of the system. As the titanium concentrate reacts with hydrochloric acid, the temperature of the system gradually increases. The reaction speed is faster in the early stage, and the system heats up faster. Maintain a constant electric heating power until the temperature of the reactor no longer rises (i.e., the temperature is stable), then it is determined that the end point of the acid leaching reaction has been reached. In the present invention, the judgment standard that the temperature no longer rises is consistent with that in the above technical solution 1, and will not be repeated here. When the end point of the acid leaching reaction is reached, the heat source can be cut off, the temperature can be lowered and the material can be discharged to obtain an artificial rutile product.

[0187] It can be seen that the above-mentioned second method for determining the endpoint of the acid leaching reaction of titanium concentrate (i.e., the electric heating technical solution, denoted as Technical Solution 2) is based on the same principle as the previous Technical Solution 1, and the only difference is that the heating method of the reaction equipment is different. There are both steam-heated reactors and electric-heated reactors in the prior art. Therefore, Technical Solution 1 adopts steam heating and Technical Solution 2 adopts electric heating, but the two have the same technical routes and belong to the same inventive concept.

[0188] The above two technical solutions of the present invention adopt the same inventive concept and technical route, which are generally as follows: (1) for the hydrochloric acid system reaction device (pressurized reactor) currently used, the heat dissipation of the pressurized reactor surface is calculated by theory, and then the accuracy of the theoretical calculation is verified on site, and corresponding corrections are made; (2) the heat dissipation of the reactor surface is supplemented by a heating device (steam / electric heating) to keep the reactor system as a constant temperature system; (3) as the reaction of titanium concentrate and hydrochloric acid in the reactor proceeds, the heat of the system accumulates and the temperature rises. As the reaction proceeds, the intensity of the reaction decreases, the difficulty increases, the reaction speed slows down, and the heating rate slows down until the reaction reaches the end point, the reaction no longer proceeds, the system temperature no longer increases, and the temperature is constant. That is, when the temperature in the reactor is constant, it is the end point of the reaction of titanium concentrate and hydrochloric acid.

[0189] The determination method of the present invention is to judge the end point of the reaction between titanium concentrate and hydrochloric acid by temperature change, and the method is simple and clear. The pressure reactor is equipped with a thermometer, and no additional equipment is required. The present invention is applicable to reactors of different specifications; for different reactors, the heat dissipation of the reactor at different temperatures can be calculated according to the surface area of ​​the reactor, the temperature of the reaction system, and the material conditions; then the reactor is used to carry out a load test to verify whether the theoretical heat dissipation is consistent with the actual situation, and the theoretical calculation results are corrected to verify the heat dissipation of the reactor at different temperatures. According to the theoretical calculation and production verification results, the present invention can realize automatic control through the heat supplement system (steam volume or electric heating power) and the temperature detection interlock in the reactor (system), so that the reactor is always in a constant temperature state. The present invention is not only suitable for steam-heated reactors, but also for electrically heated reactors. The present invention is not only suitable for the preparation of artificial rutile by hydrochloric acid leaching of Panxi titanium concentrate, but also suitable for the preparation of artificial rutile from other varieties of titanium concentrate.

[0190] The present invention also provides a method for preparing artificial rutile, comprising: adding titanium concentrate and acid solution into a reaction device, heating the system to perform an acid leaching reaction, and when it is determined that the acid leaching reaction has reached an end point, cutting off the heat source, cooling and discharging the material, and post-processing to obtain an artificial rutile product; wherein the method for determining that the acid leaching reaction has reached an end point is the determination method described in the above technical scheme.

[0191] Among them, the types, specifications, amounts, etc. of the reaction equipment, titanium concentrate, acid solution, heating reaction conditions, etc. are all consistent with those described in the previous technical solution and will not be repeated here.

[0192] The heating method is steam heating or electric heating. After the reaction reaches the end point, the heat source is cut off, the reactor is depressurized, the temperature is reduced and the material is discharged, and the solid-liquid mixture is released. Then, post-processing is performed, specifically filtering and washing, so as to obtain an artificial rutile product.

[0193] In view of the difficulty in controlling the endpoint of preparing artificial rutile by hydrochloric acid pressure leaching of Panxi titanium concentrate, the characteristics of titanium concentrate and the liquid-solid reaction mechanism of hydrochloric acid leaching are deeply analyzed to master the reaction control situation, track the reaction exothermic situation in the reactor to determine the reaction endpoint, that is, to determine the reaction endpoint by the temperature change of the reaction system. This method is simple, reliable, and easy to implement; it is reasonable and verified by experiments; this method can be implemented on existing equipment, does not require additional equipment investment, operates stably, and is easy to industrialize.

[0194] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0195] Example 1

[0196] This example is an industrial test, and the volume is 10m 3 The steel-lined ceramic, mechanically stirred, steam-heated reactor was used to carry out industrial trials for the preparation of artificial rutile from Panxi ultrafine titanium concentrate by hydrochloric acid pressure leaching. The leaching reaction was intermittent operation, with a batch of titanium concentrate input of 2.0 to 2.5 tons, a dilute hydrochloric acid concentration of 16% to 25%, and a dilute hydrochloric acid addition of 6 to 8 m 3 , the reaction temperature is controlled at 115-165°C (preferably 125-145°C). The specific process is as follows:

[0197] A) Determine the amount of steam required to maintain heat balance in the reaction equipment at the reaction temperature:

[0198] A1) The heat dissipation per unit time of the reactor is theoretically calculated by formula (1) to be 29638.9 W (i.e. 29638.9 J / s).

[0199] A2) Add 2.2 tons of quartz sand and 6.6 m 3 Dilute hydrochloric acid (concentration 18%), test system temperature T0, pass a large amount of steam to heat to 135°C, reduce the steam volume to the theoretically required steam volume m L1 (calculated by formula (2)), verify whether the system can maintain heat balance (the temperature difference within 30 minutes is 0°C, then the system maintains heat balance); if the system has a temperature drop, appropriately increase the steam volume to 6 kg / h (i.e. 1.7×10 -3 kg / s), and the result shows that the thermal balance of the system can be maintained. Therefore, the actual required steam amount to maintain the thermal balance of the system at 135°C is determined to be 6kg / h.

[0200] A3) maintaining the temperature of the reactor and the materials at 125°C, 130°C, 140°C and 145°C in sequence, repeating step A2) to determine the amount of steam required to maintain the system equilibrium at each of the above temperature points.

[0201] The results of steps A2) to A3) are shown in Table 1:

[0202] Table 1: Theoretical relationship between reaction temperature and the amount of steam required to maintain system equilibrium

[0203] Reaction temperature, °C 125 130 135 140 145 Required steam volume, kg / h 3.5 4.6 6.0 7.7 9.7

[0204] A4) Establish a standard curve with each temperature point in steps A2) to A3) as the horizontal axis and the corresponding steam volume as the vertical axis.

[0205] B) Add 2.2 tons of titanium concentrate and 6.6 tons of 3Dilute hydrochloric acid (concentration 18%), start stirring, introduce a large amount of steam for rapid heating, when the system temperature reaches 115°C (the reaction temperature is 135°C, which is 20°C lower than the reaction temperature), gradually reduce the steam volume to the required steam volume of 6kg / h; as the titanium concentrate reacts with hydrochloric acid, the system temperature gradually increases, the early reaction speed is faster, and the system heats up faster, and the above-mentioned constant steam volume is maintained until the temperature of the reactor no longer rises (i.e., the temperature is stable, and the temperature difference is 0 within 3 minutes), it is determined that the acid leaching reaction end point is reached, and the leaching time is 3 hours and 28 minutes.

[0206] After reaching the end point of the reaction, the steam is cut off, the reactor is depressurized, the temperature is lowered, the solid-liquid mixture is released, filtered and washed, and the artificial rutile product is obtained.

[0207] Comparison example:

[0208] According to the titanium concentrate acid leaching reaction process in Example 1, the artificial rutile product was obtained by adopting the traditional time-based node control method (leaching time 7 hours).

[0209] The chemical compositions of the artificial rutile products obtained by the two schemes are shown in Table 2.

[0210] Table 2: Main components of titanium concentrate and synthetic rutile (wt%)

[0211] Sample name <![CDATA[TiO2]]> FeO <![CDATA[Fe2O3]]> MgO CaO <![CDATA[Al2O3]]> <![CDATA[MnO2]]> <![CDATA[SiO2]]> Titanium concentrate (raw material) 47.1 36.45 4.78 4.58 0.633 1.4 0.729 2.65 Artificial rutile (leaching 7h) 90.38 0.23 1.93 0.24 0.15 0.37 <0.1 5.61 Artificial rutile (the present invention) 90.43 0.21 1.65 0.22 0.14 0.43 <0.1 5.15

[0212] It can be seen from the test results in Table 2 that, excluding sampling errors, the rutile grade obtained by the endpoint determination method of the present invention is basically the same as the rutile grade obtained by the endpoint determination method of the traditional method, and the leaching effects of the impurities FeO, MgO, CaO, MnO2, Al2O3, and Fe2O3 are basically the same, indicating that when the reaction reaches the endpoint during the leaching of titanium concentrate, as time goes on, the impurity elements no longer react with hydrochloric acid, and the leaching rate of the impurity elements will no longer increase, which also illustrates the accuracy of the leaching endpoint determination method of the present invention and verifies the rationality of the determination of the method of the present invention. Compared with the prior art, the present invention greatly shortens the process time, reduces energy consumption, improves production efficiency, and reduces production costs.

[0213] Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core ideas, including the best mode, and also enable any technician in the field to practice the present invention, including making and using any device or system, and implementing any combined method. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, the present invention can also be improved and modified, and these improvements and modifications also fall within the scope of protection of the claims of the present invention. The scope of patent protection of the present invention is defined by the claims and may include other embodiments that can be thought of by those skilled in the art. If these other embodiments have structural elements similar to the literal expression of the claims, or if they include equivalent structural elements that are not substantially different from the literal expression of the claims, then these other embodiments should also be included in the scope of the claims.

Claims

1. A method for determining the end point of the acid leaching reaction of titanium concentrate, characterized in that: The following steps are involved: A) Determine the amount of steam required to maintain heat balance in the reaction equipment at the reaction temperature: A1) Theoretically calculate the heat dissipation per unit time Q of the reaction equipment; A2) Place the simulated sample and acid solution into the reaction equipment, detect the system temperature T0, introduce steam to heat to the target temperature T1, and control the steam introduction amount to the theoretically required steam amount m L1 , verifying whether the system can maintain heat balance; wherein no reaction occurs between the simulated sample and the acid solution; If the system can maintain heat balance, the theoretically required steam volume m L1 That is, the actual amount of steam m required for the reaction equipment to maintain the heat balance of the system at the above target temperature T1 is determined S1 ; If the system cannot maintain heat balance, specifically, if temperature drops, the steam volume is increased, and if temperature rises, the steam volume is reduced until the system maintains heat balance. At this time, the corresponding steam volume is determined as the actual steam volume m required for the reaction equipment to maintain the heat balance of the system at the above target temperature T1. S1 ; in, Theoretically required steam volume m L1 Calculated by formula (2): m L1 =Q / C×(T1–T0) Formula (2); In formula (2): m L1 The theoretical amount of steam required to maintain the heat balance of the system at the target temperature T1, kg / s; Q is the heat dissipation per unit time of the reaction equipment obtained in step A1), J / s; C is the specific heat capacity of steam at the target temperature T2, J / (kg·K); T0 is the system temperature before steam heating, K; T1 is the target temperature after steam heating, K; A3) Select several temperature points from the reaction temperature range of the titanium concentrate acid leaching reaction as the target temperature T x Repeat step A2) to determine each target temperature T x The actual amount of steam required to maintain the heat balance of the system m Sx ; A4) using the temperature T1 in step A2) and the temperature T2 in step A3) x The horizontal axis is the actual steam quantity m required to maintain the heat balance of the system at temperature T1 in step A2). S1 and step A3) temperature T x The actual amount of steam required to maintain the heat balance of the system m Sx As the ordinate, establish a standard curve; B) adding titanium concentrate and acid solution to the reaction equipment, introducing steam to heat the system for acid leaching reaction, controlling the steam amount to the actual steam amount required to maintain the heat balance of the system corresponding to the target temperature set for the reaction equipment, and maintaining the heat balance of the reaction equipment; as the acid leaching reaction proceeds, when the temperature of the reaction equipment no longer rises but remains stable, it is determined to be the end point of the acid leaching reaction.

2. A method for determining the end point of the acid leaching reaction of titanium concentrate, characterized in that: The following steps are involved: A") Determine the electric heating power required for the reaction equipment to maintain heat balance at the reaction temperature: A1) Theoretical calculation of the heat dissipation per unit time Q of the reaction equipment: A2″) Place the simulated sample and the acid solution into the reaction equipment, detect the system temperature T0, and heat it to the target temperature T1 by power, and control the electric heating power to be the theoretical required electric heating power P L1 , verifying whether the system can maintain heat balance; wherein no reaction occurs between the simulated sample and the acid solution; If the system can maintain heat balance, the theoretical required electric heating power P L1 That is, the actual required electric heating power P of the reaction equipment to maintain the heat balance of the system at the above target temperature T1 is determined. s1 ; If the system cannot maintain heat balance, specifically, if temperature drops, the electric heating power is increased, and if temperature rises, the electric heating power is reduced until the system maintains heat balance. At this time, the corresponding electric heating power is determined as the actual electric heating power P required for the reaction equipment to maintain the heat balance of the system at the above target temperature T1. S1 ; in, Theoretical required electric heating power P L1 Calculated by formula (2): P L1 =Q formula (2″); In formula (2″): P L1 The theoretical electric heating power required to maintain the thermal balance of the system at the target temperature T1, W; Q is the heat dissipation per unit time of the reaction equipment obtained in step A1), W; A3″) Select several temperature points from the reaction temperature range of the titanium concentrate acid leaching reaction as the target temperature T x Repeat step A2) to determine each target temperature T x The actual electric heating power P required to maintain the thermal balance of the system Sx ; A4″) with the temperature T1 in step A2) and the several temperatures T in step A3) x = is the horizontal axis, and the actual electric heating power P required to maintain the thermal balance of the system at temperature T1 in step A2) is s1 and step A3) temperature T x The actual electric heating power P required to maintain the thermal balance of the system Sx As the ordinate, establish a standard curve; B") adding titanium concentrate and acid solution into the reaction equipment, applying power to heat the system for acid leaching reaction, controlling the electric heating power to the actual electric heating power required to maintain the heat balance of the system corresponding to the target temperature set for the reaction equipment, and maintaining the heat balance of the reaction equipment; as the acid leaching reaction proceeds, when the temperature of the reaction equipment no longer rises but remains stable, it is determined to be the end point of the acid leaching reaction.

3. The determination method according to claim 1, characterized in that: In step A2), the simulation sample is quartz sand; and the acid solution is hydrochloric acid.

4. The determination method according to claim 1, characterized in that: In step A2): The operation mode of heating the target temperature T1 by introducing steam is as follows: firstly introduce excess steam into the heating system, and when the target temperature T1 is approached, reduce the amount of steam introduced to the theoretically required amount of steam m L1 , continue heating to the target temperature T1; The criterion for judging whether the system maintains thermal balance is that the system temperature fluctuates to 0°C within a period of ≥30 minutes.

5. The determination method according to claim 1, characterized in that: The total number of temperature points selected in steps A2)-A3) is ≥5; The step length between the selected temperature points is 5 to 15°C.

6. The determination method according to claim 2, characterized in that: In step A2″), the simulation sample is quartz sand; and the acid solution is hydrochloric acid.

7. The determination method according to claim 2, characterized in that: In step A2″): The operation mode of heating to the target temperature T1 is: firstly, the heating system is heated at a high power, and when the target temperature T1 is approached, the electric heating power is reduced to the theoretical required electric heating power P L1 , continue heating to the target temperature T1; The criterion for judging whether the system maintains thermal balance is that the system temperature fluctuates to 0°C within a period of ≥30 minutes.

8. The determination method according to claim 2, characterized in that: The total number of temperature points selected in steps A2″)-A3″) is ≥5; The step length between the selected temperature points is 5 to 15°C.

9. The determination method according to claim 4 or 7, characterized in that: The temperature close to the target temperature T1 is 15 to 30° C. lower than the target temperature T1.

10. A method for preparing artificial rutile, characterized in that: include: Add titanium concentrate and acid solution to the reaction equipment, heat the system to carry out acid leaching reaction, and when it is determined that the acid leaching reaction reaches the end point, cut off the heat source, cool down the material, and perform post-processing to obtain an artificial rutile product; Wherein, the method for determining that the acid leaching reaction has reached an endpoint is the determination method according to any one of claims 1 to 9.