Method for determining the end point of the reaction of acid leaching of titanium concentrate, and method for preparing synthetic rutile

Abstract

The application provides a method for determining the end point of titanium concentrate acid leaching reaction and a method for preparing artificial rutile. The application is directed to the current reaction device (pressurized reaction kettle) of hydrochloric acid system, heat dissipation of the pressurized reaction kettle is calculated by the Ritten method, then the accuracy of the theoretical calculation is verified on site, and corresponding correction is made; then the surface heat dissipation of the reaction kettle is supplemented by a heating device (steam / electric heating), so that the reaction kettle system is a constant temperature system; as the reaction of titanium concentrate and hydrochloric acid in the reaction kettle proceeds, the heat of the system accumulates, the temperature rises, as the reaction proceeds, the reaction intensity decreases, the difficulty increases, the reaction speed slows down, the temperature rising 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. When the temperature in the reaction kettle is constant, it is the end point of the reaction of titanium concentrate and hydrochloric acid. The determination method of the application 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 present application relates to the chemical industry, in particular to a method for determining the end point of a titanium concentrate acid leaching reaction, and a method for preparing artificial rutile. BACKGROUND

[0002] The Panxi region is rich in titanium resources, and currently accounts for more than 90% of the proven reserves in China. The Panzhihua titanium concentrate is a typical titanium-iron ore, with good acid solubility, and is widely used in the production of titanium dioxide by the sulfuric acid method; however, the product grade is low, and the impurity content is high, especially the content of calcium, magnesium and other impurities, and after smelting by an electric furnace, the CaO+MgO content in the acid-soluble titanium slag is as high as 7% to 11%, which cannot be directly used for the production of titanium dioxide and titanium metal by the boiling chlorination method.

[0003] With the current huge environmental pressure and increasing product competition, the production capacity of sulfuric acid titanium dioxide is gradually decreasing, and the production capacity of chlorination titanium dioxide is gradually increasing. Developed countries basically use chlorination titanium dioxide production technology, and in recent years, China is also promoting the upgrading of the titanium dioxide industry, encouraging the development of chlorination titanium dioxide, and the boiling chlorination titanium dioxide technology is developing rapidly. In 2023, the production capacity of chlorination titanium dioxide reached nearly 1000 kt / a, and the production capacity under construction or preparation will reach 1500 kt / a. In addition to the increase in metal titanium production capacity, the demand for high-quality titanium raw materials will increase significantly, and there may be a shortage of supply.

[0004] Currently, the high-quality raw materials used in the production of chlorination titanium dioxide in China mainly come from two sources: one part is imported high-quality titanium-iron sand (low calcium and magnesium) which is smelted by an electric furnace to obtain TiO2 with a grade of 90% or 92%, and low calcium and magnesium high-titanium slag; the other part is directly imported high-quality titanium-rich raw materials (natural rutile, artificial rutile and upgraded titanium slag) that meet the specifications. Therefore, high-quality titanium raw materials mainly depend on foreign imports, and the raw materials are subject to the control of others, which will affect the development of China's titanium industry to a high-end level.

[0005] A large number of researches on titanium resources in Panxi region have been carried out by domestic research institutes and colleges. Due to low grade of titanium concentrate in Panzhihua, high content of non-ferrous impurities such as calcium and magnesium, and low grade of titanium slag obtained after electric furnace smelting, the titanium slag cannot be directly used as raw material for titanium dioxide by boiling chlorination method. A large number of researches show that the acid leaching method for preparing artificial rutile is one of effective processes for preparing high-quality titanium raw material from Panzhihua titanium concentrate with industrialization prospect. The acid leaching method for preparing artificial rutile is that the impurity elements such as FeO, MgO, CaO, MnO and Al2O3 in the titanium concentrate react with dilute hydrochloric acid to generate soluble salt into liquid phase, and TiO2 is enriched in solid phase to obtain high-quality titanium-rich material. However, the reaction must be carried out in a closed reactor under certain temperature and pressure conditions to obtain qualified products. Since the reaction is carried out in a closed reactor, the reaction endpoint is difficult to determine, and if the reaction is stopped before completion, the product quality and value of the titanium-rich material will be seriously affected. Therefore, the reaction time is usually prolonged to ensure the product quality, which not only causes energy waste, but also affects the production rhythm, causes low equipment operation rate, increases production cost and reduces the economy of the whole process. SUMMARY

[0006] Therefore, the application provides a determination method for reaction endpoint of titanium concentrate acid leaching and a preparation method of artificial rutile. The determination method for reaction endpoint of titanium concentrate acid leaching can accurately determine the reaction endpoint of acid leaching, improve production efficiency and reduce production cost.

[0007] The application provides a determination method for reaction endpoint of titanium concentrate acid leaching, which comprises the following steps:

[0008] A) determining steam amount required for reaction equipment to maintain heat balance at reaction temperature:

[0009] A1) theoretically calculating heat dissipation amount Q of the reaction equipment per unit time;

[0010] A2) putting simulation sample and acid liquid into the reaction equipment, detecting system temperature T0, heating to target temperature T1 by steam, controlling steam input amount to be theoretical steam amount m L1 , and verifying whether the system can maintain heat balance; wherein the simulation sample does not react with the acid liquid;

[0011] If the system can maintain heat balance, the theoretical steam amount m L1 is determined as actual steam amount m S1 required for the reaction equipment to maintain heat balance at the target temperature T1.

[0012] If the system cannot maintain heat balance, specifically, if temperature drop occurs, then the steam amount is increased, if temperature rise occurs, then the steam amount is decreased, until the system maintains heat balance, at this time, the corresponding steam amount is determined as the actual required steam amount m of the reaction equipment at the target temperature T1 to maintain heat balance of the system S1 ;

[0013] wherein,

[0014] theoretical required steam amount m L1 The theoretical required steam amount m is calculated by formula (2):

[0015] m L1 = Q / C x (T1-T0) formula (2);

[0016] In formula (2):

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

[0018] Q is the heat dissipation amount 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) selecting several temperature points from the reaction temperature range of the titanium concentrate acid leaching reaction as target temperatures T x , repeating step A2), and determining the actual required steam amount m x at each target temperature T Sx to maintain heat balance of the system;

[0023] A4) taking the temperature T1 in step A2) and the several temperatures T x in step A3) as the horizontal coordinates, and taking the actual required steam amount m S1 at the temperature T1 in step A2) to maintain heat balance of the system and the actual required steam amount m x at the temperature T Sx in step A3) to maintain heat balance of the system as the vertical coordinates, to establish a standard curve;

[0024] B) Add titanium concentrate and acid to the reaction equipment, and introduce steam to heat the system for acid leaching reaction. Control the amount of steam at the actual amount of steam required to maintain the thermal balance of the system at the target temperature set in the reaction equipment. When the temperature of the reaction equipment stops rising and remains stable as the acid leaching reaction proceeds, it is determined to be the end point of the acid leaching reaction.

[0025] This invention also provides a method for determining the endpoint of the acid leaching reaction of titanium concentrate, comprising the following steps:

[0026] A) Determine the electrical heating power required to maintain thermal balance in the reaction equipment at the reaction temperature:

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

[0028] A2") Place the simulated sample and acid solution into the reaction apparatus, monitor the system temperature T0, and heat to the target temperature T1, controlling the electric heating power to the theoretically required electric heating power P. L1 To verify whether the system can maintain thermal balance; wherein, the simulated sample does not react with the acid solution;

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

[0030] If the system cannot maintain thermal balance, specifically, if a temperature drop occurs, the electric heating power is increased; if a temperature rise occurs, the electric heating power is decreased, until the system maintains thermal balance. The corresponding electric heating power at this point is determined as the actual electric heating power P required by the reaction equipment to maintain thermal balance at the target temperature T1. S1 ;

[0031] in,

[0032] Theoretically required electric heating power P L1 The result is obtained by calculation using formula (2"):

[0033] P L1 =Q-form (2");

[0034] In formula (2"):

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

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

[0037] A3") Select several temperature points within the reaction temperature range of the titanium concentrate acid leaching reaction as target temperatures 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") uses the temperature T1 in step A2) and several temperatures T in step A3). x The x-axis represents the actual electric heating power P required to maintain the system's thermal balance at temperature T1 in step A2). s1 and the temperature T in step A3) x The actual electric heating power P required to maintain the thermal balance of the system Sx Establish a standard curve with the vertical axis as the ordinate;

[0039] B") Add titanium concentrate and acid to the reaction equipment, and heat the system with electricity to carry out the acid leaching reaction. Control the electric heating power at the actual electric heating power required to maintain the thermal balance of the system at the target temperature set by the reaction equipment. Maintain the thermal balance of the reaction equipment. When the temperature of the reaction equipment no longer rises and remains stable as the acid leaching reaction proceeds, it is determined to be the end point of the acid leaching reaction.

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

[0041] Preferably, in step A2):

[0042] The operation method for heating the system to the target temperature T1 by introducing steam is as follows: first, an excess of steam is introduced to heat the system; when the temperature approaches the target temperature T1, the steam introduction rate is reduced to the theoretically required steam rate m. L1 Continue heating to the target temperature T1;

[0043] The criterion for determining whether a system maintains thermal equilibrium is: the system temperature fluctuates at 0℃ within a time period of ≥30 minutes.

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

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

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

[0047] Preferably, in step A2"):

[0048] The operation mode of the electric heating to the target temperature T1 is: first high-power electric heating system, when close to the target temperature T1, reduce the electric heating power to the theoretical required electric heating power P L1 , continue to heat to the target temperature T1;

[0049] The determination criterion for maintaining the heat balance of the system is that the temperature fluctuation of the system is 0 DEG C within a period of >=30 min.

[0050] Preferably, the number of selected temperature points in steps A2" to A3" is >=5.

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

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

[0053] The application also provides a preparation method of artificial rutile, comprising:

[0054] Titanium concentrate and acid solution are added to the reaction equipment, and the system is heated for acid leaching reaction, when the acid leaching reaction reaches the end point, the heat source is cut off, the temperature is lowered, the material is discharged, and the post-treatment is carried out to obtain the artificial rutile product.

[0055] The method for determining that the acid leaching reaction reaches the end point is the determination method described in the above technical solution.

[0056] In the prior art, many patents have been applied for using Panxi titanium concentrate and hydrochloric acid leaching to prepare artificial rutile, but none of them involves the determination of the leaching reaction end point. Panxi uses self-produced ultra-fine titanium concentrate and hydrochloric acid to prepare artificial rutile by pressure leaching, which uses a pressure reaction kettle, and through steam heating, the reaction temperature is reached, and the termination of the reaction is controlled by controlling the reaction time. Because the reaction end point is uncertain (i.e. it is uncertain when the reaction stops), in order to ensure that the reaction is fully carried out and the product quality, the process time is usually extended, 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, etc. Adverse effects. That is, the prior art does not focus on determining the leaching reaction end point and ending the reaction in time at the reaction end point, but uses the way of extending the process time to ensure that the reaction end point is exceeded.

[0057] The technical route of the present application is as follows: (1) for the currently used hydrochloric acid system reaction device (pressurized reaction kettle), the surface heat dissipation of the pressurized reaction kettle is calculated by the Leung method, and then the accuracy of the theoretical calculation is verified on site, and appropriate correction is made; (2) the surface heat dissipation of the reaction kettle is supplemented by the heating device (steam / electric heating), so as to maintain the reaction kettle system as a constant temperature system; (3) as the reaction of titanium concentrate and hydrochloric acid in the reaction kettle proceeds, the heat of the system accumulates, the temperature rises, and as the reaction proceeds, the reaction intensity decreases and the difficulty increases, the reaction speed slows down, the temperature rises slowly, 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 reaction kettle is constant, it is the end point of the reaction of titanium concentrate and hydrochloric acid.

[0058] The present application determines the end point of the reaction by tracking the reaction heat release in the reactor, that is, by the temperature change of the reaction system to determine the end point of the reaction, so as to realize accurate control; and further greatly shortens the process time and reduces the energy consumption, improves the production efficiency, and reduces the production cost. DETAILED DESCRIPTION

[0059] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0060] In this document, the technical features described in an open way include both the closed technical solution consisting of the listed features and the open technical solution including 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] In this document, when referring to a numerical range, unless otherwise specified, the numerical range is considered to be continuous and includes the minimum and maximum values of the range, as well as every value between the minimum and maximum values. Further, when the range is referred to as an integer, every integer between the minimum and maximum values of the range is included. In addition, when multiple ranges are provided to describe a feature or characteristic, the ranges can be combined. In other words, unless otherwise indicated, all ranges disclosed herein are to be interpreted as including any and all sub-ranges subsumed therein.

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

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

[0065] A) determining the steam amount required for the reaction equipment to maintain heat balance at the reaction temperature:

[0066] A1) theoretically calculating the heat dissipation amount Q of the reaction equipment per unit time;

[0067] A2) placing the simulation sample and the acid liquid into the reaction equipment, detecting the system temperature T0, heating to the target temperature T1 by steam input, and controlling the steam input amount to be the theoretically required steam amount m L1 , and verifying whether the system can maintain heat balance; wherein the simulation sample does not react with the acid liquid;

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

[0069] If the system cannot maintain heat balance, specifically, if the temperature decreases, the steam amount is increased, if the temperature increases, the steam amount is decreased, until the system maintains heat balance, and the steam amount corresponding to this time is determined as the actual required steam amount m S1 of the reaction equipment to maintain heat balance of the system at the target temperature T1.

[0070] wherein,

[0071] the theoretically required steam amount m L1 is calculated by formula (2):

[0072] m L1 = Q / C x (T1-T0) formula (2).

[0073] In formula (2),

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

[0075] Q is the heat dissipation amount of the reaction equipment per unit time 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 target temperatures T x , repeat step A2), and determine the actual required steam amount m x required to maintain the heat balance of the system at each target temperature T Sx ;

[0080] A4) using the temperature T1 in step A2) and the several temperatures T x in step A3) as the horizontal coordinates, and using the actual required steam amount m S1 required to maintain the heat balance of the system at the temperature T1 in step A2) and the actual required steam amount m x required to maintain the heat balance of the system at the temperature T Sx in step A3) as the vertical coordinates, a standard curve is established.

[0081] B) adding titanium concentrate and acid solution into the reaction equipment, and heating the system by introducing steam to perform acid leaching reaction, the steam amount is controlled at the actual required steam amount required to maintain the heat balance of the system at the target temperature set by the reaction equipment, and the heat balance of the reaction equipment is maintained; as the acid leaching reaction proceeds, when the temperature of the reaction equipment no longer rises and remains stable, it is determined that the acid leaching reaction endpoint is reached.

[0082] In view of the difficulty in determining the endpoint of the current Panxi titanium concentrate hydrochloric acid pressure leaching to prepare synthetic rutile and the problem of not being easy to accurately control, the applicant found through in-depth analysis of the material characteristics of titanium concentrate and the reaction mechanism of hydrochloric acid leaching liquid solid that the reaction of impurity elements FeO, MgO, CaO, MnO, Al2O3, etc. in titanium concentrate with hydrochloric acid is an exothermic reaction. If the heat balance of the reaction system is maintained, the reaction endpoint can be accurately and timely determined by temperature change, so the present application determines the reaction endpoint by tracking the reaction heat release in the reactor, that is, by the temperature change of the reaction system to determine the reaction endpoint, thereby achieving accurate control.

[0083] [About step A]:

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

[0085] Regarding step A1) : theoretically calculating the heat dissipation amount Q of the reaction equipment per unit time.

[0086] In the present application, the reaction equipment is preferably a reaction kettle, specifically a pressure reaction kettle, which is a commonly used reaction device for the current titanium concentrate acid leaching system. In the process of titanium concentrate acid leaching reaction, the reaction kettle itself will dissipate heat, and the present application theoretically calculates the surface heat dissipation of the reaction kettle in advance.

[0087] The theoretical calculation of the heat dissipation amount Q of the reaction device per unit time is not particularly limited in the present application, and can be calculated according to the method known in the art, for example, the heat dissipation amount Q of the reaction device can be calculated according to the external surface area of the reaction device, the convective heat transfer coefficient of the reaction device, the reaction system temperature, and the like. Specifically, the heat dissipation amount Q of the reaction device per unit time can be theoretically calculated by formula (1):

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

[0089] In formula (1),

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

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

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

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

[0094] Ta is the ambient temperature, K.

[0095] In the present application, in formula (1) above, when there are multiple choices for the units corresponding to each parameter, various unit forms can be adopted, 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 unit of parameters Ts and Ta can also be unified as K. This is only an adaptive change in unit form, and the essence of the scheme does not change, which also belongs to the protection scope of the present application. In this paper, the same applies to other places, and will not be repeated here.

[0096] Regarding step A2) :

[0097] A2) Put the simulation sample and acid liquid into the reaction device (wherein no reaction occurs between the simulation sample and the acid liquid), detect the system temperature T0, and heat to the target temperature T1 by passing in steam, control the steam input amount to be the theoretical required steam amount m L1 , and verify whether the system can maintain heat balance; if the system can maintain heat balance, the theoretical required steam amount m L1 is determined as the actual required steam amount m S1 of the reaction device to maintain the heat balance of the system at the target temperature T1; if the system cannot maintain heat balance, specifically, if the temperature drops, increase the steam amount, if the temperature rises, reduce the steam amount, until the system maintains heat balance, at which time the corresponding steam amount is determined as the actual required steam amount m S1 of the reaction device to maintain the heat balance of the system at the target temperature T1.

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

[0099] In the present application, the acid liquid is preferably hydrochloric acid, and more preferably dilute hydrochloric acid. The mass percentage concentration of the dilute hydrochloric acid is preferably 16% to 25%, and can be 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, or 25%.

[0100] In the present application, the dosage relationship between the simulation sample and the acid liquid is performed according to the dosage relationship between the titanium concentrate and the acid liquid in the acid leaching of titanium concentrate in the art.

[0101] In the present application, the simulation sample and the acid liquid are placed in the reaction device, and the system temperature T0 is detected in advance 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 application, 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 to 165℃, and preferably 125 to 145℃. In the present application, any temperature point in the above reaction temperature range is selected as the target temperature for this time, and steam is introduced to heat to the target reaction temperature.

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

[0103] In the present application, the "introducing steam to heat to the target temperature T1" has two operation modes, which are as follows: (1) Mode one: introducing the theoretical required amount of steam m L1 to heat to the target temperature T1. (2) Mode two: first introducing excess steam to heat the system, and when the target temperature T1 is approached, reducing the steam introduction amount to the theoretical required amount of steam m L1 , and continuing to heat to the target temperature T1. In mode two, the excess steam refers to the amount of steam that is more than the theoretical required amount of steam m L1More steam. The target temperature T1 to be approached is preferably 15-30℃ lower than the target temperature T1, i.e. 15-30℃ lower than the target temperature T1, reaching T1-(15-30)℃, and can be specifically T1-15℃, T1-16℃, T1-17℃, T1-18℃, T1-19℃, T1-20℃, T1-21℃, T1-22℃, T1-23℃, T1-24℃, T1-25℃, T1-26℃, T1-27℃, T1-28℃, T1-29℃, T1-30℃. A large amount of steam is first introduced to rapidly raise the temperature of the system, so that the target temperature is approached more quickly. When the target temperature is about to be approached, the amount of steam is reduced, and the theoretical steam amount m required is used instead L1 The system continues to be heated to the target temperature T1. The present application preferably adopts mode two, which can save process time and improve process efficiency.

[0104] In the present application, after heating to the target temperature T1 by introducing steam, the theoretical steam amount m L1 The steam continues to be introduced to maintain the heat balance of the system.

[0105] In the present application, the theoretical steam amount m L1 is calculated by formula (2):

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

[0107] In formula (2):

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

[0109] Q is the heat dissipation amount per unit time of the reaction device 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 temperature of the system before steam heating, K;

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

[0113] In the present application, after heating to the target temperature T1 by introducing steam, the theoretical steam amount m L1Steam is continuously introduced to maintain the thermal balance of the system. After a period of time, it is verified whether the system can truly maintain thermal balance. In this invention, the criterion for determining whether the system maintains thermal balance is: the system temperature fluctuation is 0℃ 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 if the system temperature fluctuates during this period. If there is no fluctuation (the fluctuating temperature is 0℃), that is, the system temperature is constant, and it is considered that the system maintains thermal balance. The preferred monitoring time period is 30 to 45 minutes, specifically 30 minutes, 35 minutes, 40 minutes, 45 minutes, and more preferably 30 minutes. In this invention, steam is first introduced to heat to the target temperature T1. Since the reaction vessel itself dissipates heat, causing heat loss, a supplementary heating system (steam heating) is used to supply the theoretically required amount of steam m. L1 Continue to introduce steam to try to compensate for heat loss and maintain the thermal balance of the system, and then verify whether the theoretically calculated amount of steam can truly maintain the thermal balance of the system.

[0114] The verification results and response methods are as follows:

[0115] If the system can maintain heat balance, then the theoretically required amount of steam m L1 That is, the actual amount of steam m required to maintain the thermal balance of the system at the target temperature T1 is determined. S1 That is, the theoretically required steam quantity m L1 Compared with the actual required steam volume m S1 They are equal and require no correction.

[0116] If the system cannot maintain heat balance, specifically, if a temperature drop occurs, the steam quantity is increased; if a temperature rise occurs, the steam quantity is decreased, until the system maintains heat balance. The corresponding steam quantity at this point is determined as the actual steam quantity m required by the reaction equipment to maintain heat balance at the target temperature T1. S1 This situation refers to the theoretically required steam quantity m. L1 The system failed to maintain thermal equilibrium, therefore, the amount of steam was increased or decreased to adjust the theoretically required steam quantity m. L1 Adjustments are made until the system can maintain thermal equilibrium; the steam quantity at this point is determined as the actual required steam quantity m. S1 .

[0117] The above is equivalent to calculating the theoretically required steam volume m. L1 Subsequently, a load test was conducted on the reactor to verify whether the theoretically calculated heat dissipation matched the actual situation, and the theoretical calculation results were corrected (corrections were made if they did not match), thereby obtaining the actual amount of steam m required to maintain the system's heat balance at a target temperature T1. S1 .

[0118] Regarding step A3) :

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

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

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

[0122] In the present application, the total number of temperature points selected in steps A2)-A3) is preferably ≥5. The step size between the selected temperature points is preferably 5-15℃, and can be 5℃, 10℃, or 15℃. The step size refers to the temperature interval between the temperature points. Taking a step size of 5℃ as an example, if the first temperature point is 125℃, the remaining temperature points are 130℃, 135℃, 140℃, 145℃, and so on. According to the characteristics of the titanium concentrate pressure leaching reaction, for steps A2)-A3) in the present application, the preferred temperature points are 125℃, 130℃, 135℃, 140℃, and 145℃, and the actual steam amounts required to maintain the heat balance of the system at the above five temperature points are obtained.

[0123] Regarding step A4) :

[0124] A4) establish a standard curve with the temperature T1 in step A2) and the several temperatures T x in step A3) as the horizontal coordinates, and the actual steam amount m S1 required to maintain the heat balance of the system at the temperature T1 in step A2) and the actual steam amount m x required to maintain the heat balance of the system at the temperature T Sx in step A3) as the vertical coordinates.

[0125] In the present application, step A4) is to establish a standard curve between the temperature points selected in steps A2)-A3) and the actual steam amount 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 setting temperature of the titanium concentrate acid leaching reaction is T, the actual steam amount required to maintain the heat balance of the system is calculated in advance through the standard curve S In the subsequent actual acid leaching reaction, the steam amount is introduced to maintain the system balance.

[0126] In the present application, when drawing the standard curve, the temperature points can also be used as the ordinate and the steam amount corresponding to the temperature points can be used as the abscissa. This is only different in form from the drawing method described above, but the essence is to establish a standard curve between the temperature points and the steam amount, which also belongs to the protection scope of the present application.

[0127] [About step B]:

[0128] B) Adding titanium concentrate and acid solution into the reaction equipment, introducing steam to heat the system for acid leaching reaction, controlling the steam amount at the actual steam amount required to maintain the heat balance of the system at the target temperature set by the reaction equipment, maintaining the heat balance of the reaction equipment; as the acid leaching reaction proceeds, when the temperature of the reaction equipment no longer rises and remains stable, it is determined that the acid leaching reaction endpoint is reached.

[0129] In the present application, the reaction equipment is preferably a reaction kettle, specifically a pressurized reaction kettle, which is a commonly used reaction device for the current titanium concentrate acid leaching system. It is preferred to use the same specification reaction equipment as step A).

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

[0131] In the present application, the amount of titanium concentrate and acid solution is controlled as follows: the liquid-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, or 3.5:1, more preferably 3.0:1. The above liquid-solid ratio refers to the mass ratio of liquid to solid. The total volume of the mixture can be determined according to the filling rate of the reactor.

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

[0133] In the present application, the above acid leaching reaction process is preferably accompanied by stirring; that is, mechanical stirring is accompanied during the heating reaction process after the addition of materials.

[0134] In this invention, there are two operating methods for "heating the system with steam to carry out acid leaching reaction", as follows: (1) Method 1: Introduce the actual required amount of steam m sx Continue heating until the target temperature T is reached. x (2) Method 2: First, introduce excess steam to heat the system, and wait until it approaches the target temperature T. x At that time, the steam input rate is controlled to be the actual required steam quantity m. sx It directly reaches the target temperature T. x In Method Two, the excess steam refers to a steam quantity m greater than the actual required steam quantity. sx Larger vapor. The temperature to be approached is T. x Preferably below the target temperature T x 15~30℃, that is, compared to the target temperature T x 15-30℃ lower, reaching 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 rapidly heat the system, allowing it to approach the target temperature more quickly. When it is almost at the target temperature, reduce the steam flow rate to the actual required steam flow rate, m. sx Continue to heat the system to the target temperature T. x The present invention preferably adopts method two, which can save process time and improve process efficiency.

[0135] In this invention, steam is introduced to heat the material to the target temperature T. x Then, according to the actual required steam quantity m sxContinuing to pass in steam to maintain the system heat balance. With the reaction of titanium concentrate and hydrochloric acid, the system temperature gradually rises, the early reaction rate is faster, the system temperature rises faster, keep constant steam amount, until the reactor temperature is no longer rising (i.e. temperature stable), then determine the acid leaching reaction endpoint. In the present application, the temperature no longer rises specifically refers to the system temperature fluctuation is 0℃ within a period of ≥2min; wherein, the period of ≥2min refers to continuously monitor for 2min or more, to see if the system temperature still rises within this period, if not (fluctuation temperature is 0℃), that is, the system temperature is constant, then it is considered that the acid leaching reaction endpoint is reached. Wherein, the above monitoring period is selected to be 2-5min, specifically can be 2min, 3min, 4min, 5min, preferably 3min. When the acid leaching reaction endpoint is reached, the heat source can be cut off, the temperature is lowered and the discharge is obtained to obtain the synthetic rutile product.

[0136] The present application also provides another determination method of titanium concentrate acid leaching reaction endpoint, comprising the following steps:

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

[0138] A1, theoretically calculating the heat dissipation amount Q of the reaction equipment per unit time;

[0139] A2") putting the simulation sample and acid liquid into the reaction equipment, detecting the system temperature T0, heating to the target temperature T1 by controlling the electric heating power to be the theoretically required electric heating power P L1 , verifying whether the system can maintain heat balance; wherein, the simulation sample and the acid liquid do not react with each other;

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

[0141] If the system cannot maintain heat balance, specifically, if the temperature drops, the electric heating power is increased, if the 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 required electric heating power P S1 of the reaction equipment to maintain system heat balance at the target temperature T1;

[0142] Wherein,

[0143] The theoretically required electric heating power P L1 is calculated by formula (2"):

[0144] P L1 =Q formula (2");

[0145] In formula (2''):

[0146] P L1 P is the actual required electric heating power for maintaining the heat balance of the system at the target temperature T1, W;

[0147] Q is the heat dissipation of the reaction device per unit time, W;

[0148] A3'') a plurality of temperature points are selected from the reaction temperature range of the titanium concentrate acid leaching reaction as target temperatures T x , and step A2) is repeated to determine the actual required electric heating power P x for maintaining the heat balance of the system at each target temperature T Sx ;

[0149] A4'') with the temperature T1 in step A2) and the plurality of temperatures T x in step A3) as the horizontal coordinates, and the actual required electric heating power P s1 for maintaining the heat balance of the system at the temperature T1 in step A2) and the actual required electric heating power P x for maintaining the heat balance of the system at the temperature T Sx in step A3) as the vertical coordinates, a standard curve is established;

[0150] B'') titanium concentrate and acid solution are added to the reaction device, and the system is heated by electricity for acid leaching reaction, the electric heating power is controlled at the actual required electric heating power for maintaining the heat balance of the system at the target temperature set by the reaction device, and the heat balance of the reaction device is maintained; as the acid leaching reaction proceeds, when the temperature of the reaction device no longer rises and remains stable, it is determined that the acid leaching reaction endpoint is reached.

[0151] [Regarding step A'']:

[0152] A'') determine the electric heating power required for maintaining the heat balance of the reaction device at the reaction temperature.

[0153] Regarding step A1) : theoretically calculate the heat dissipation Q of the reaction device per unit time.

[0154] This step is the same as the first step in the first titanium concentrate acid leaching reaction endpoint determination method (referred to as technical solution 1) described above, and will not be repeated here.

[0155] Regarding step A2") :

[0156] A2'') the simulation sample and the acid solution are placed in the reaction device (wherein no reaction occurs between the simulation sample and the acid solution), the system temperature T0 is detected, and the electric heating power is controlled at the theoretical required electric heating power PL1 , verify whether the system can maintain heat balance; if the system can maintain heat balance, the theoretical required electric heating power P L1 is determined as the actual required electric heating power P s1 of the reaction device to maintain the heat balance of the system at the target temperature T1; if the system cannot maintain heat balance, specifically, if the temperature drops, the electric heating power is increased, and if the temperature rises, the electric heating power is reduced until the system maintains heat balance, at which time the corresponding electric heating power is determined as the actual required electric heating power P S1 of the reaction device to maintain the heat balance of the system at the target temperature T1.

[0157] In the present application, the types and amounts of the simulation sample and the acid solution are consistent with those in the technical solution 1 described above, and will not be repeated here.

[0158] In the present application, the simulation sample and the acid solution are placed in the reaction device, and the system temperature T0 is detected before heating, that is, the system temperature before heating is recorded. Then, the target temperature T1 is heated by power. In the present application, the target temperature T1 is selected from the reaction temperature of the titanium concentrate acid leaching reaction in the art, and generally, the reaction temperature of the titanium concentrate acid leaching reaction is 115-165℃, and preferably 125-145℃. In the present application, any temperature point in the above reaction temperature range is selected as the target temperature of this time, and the target reaction temperature is heated by power.

[0159] In the present application, the above acid leaching reaction process is preferably accompanied by stirring; that is, after the material is added, mechanical stirring is accompanied during the heating reaction process.

[0160] In the present application, the "heating to the target temperature T1 by power" has two operation modes, which are as follows: (1) Mode one: according to the theoretical required electric heating power P L1 heating to the target temperature T1. (2) Mode two: first, high-power power is applied to heat the system, and when the target temperature T1 is approached, the electric heating power is reduced to the theoretical required electric heating power P L1 , and the heating to the target temperature T1 is continued. In mode two, the first high-power power is applied to heat the system, which means that the electric heating power is higher than the theoretical required electric heating power P L1Larger electric heating power. The target temperature T1 to be approached is preferably 15-30℃ lower than the target temperature T1, i.e. 15-30℃ lower than the target temperature T1, reaching T1-(15-30)℃, and can be specifically T1-15℃, T1-16℃, T1-17℃, T1-18℃, T1-19℃, T1-20℃, T1-21℃, T1-22℃, T1-23℃, T1-24℃, T1-25℃, T1-26℃, T1-27℃, T1-28℃, T1-29℃, T1-30℃. First, a large power is supplied to rapidly heat the system, so that it can approach the target temperature more quickly. When it is about to approach the target temperature, the electric heating power is reduced to the theoretically required electric heating power P L1 , and the system continues to be heated to the target temperature T1. The present application preferably adopts mode two, which can save process time and improve process efficiency.

[0161] In the present application, after heating to the target temperature T1, the theoretically required electric heating power P L1 is used to continue to supply power to maintain the heat balance of the system.

[0162] In the present application, the theoretically required electric heating power P L1 is calculated by formula (2''):

[0163] P L1 = Q formula (2'');

[0164] In formula (2''):

[0165] P L1 is the theoretically required electric heating power, W, for maintaining the heat balance of the system at the target temperature T1;

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

[0167] In the present application, after electric heating to the target temperature T1, the theoretically required electric heating power P L1 is used to continue to supply power to maintain the heat balance of the system, and after a period of time, it is verified whether the system can indeed maintain the heat balance. In the present application, the criterion for judging whether the system maintains the heat balance is that the system temperature fluctuates by 0℃ within a period of ≥30 min; wherein the period of ≥30 min refers to continuously monitoring for 30 min or more to see whether the system temperature fluctuates within this period of time, and if there is no fluctuation (fluctuation temperature is 0℃), i.e. the system temperature is constant, it is considered that the system maintains the heat balance. Preferably, the above-mentioned monitoring period is 30-45 min, and can be specifically 30 min, 35 min, 40 min, 45 min, and more preferably 30 min.

[0168] The verification results and the coping methods are as follows:

[0169] If the system can maintain heat balance, the theoretical required electric heating power P L1 , i.e. the actual required electric heating power P s1 of the reaction equipment at the target temperature T1 to maintain the heat balance of the system. L1 , i.e. the actual required electric heating power P s1 is equal to the theoretical required electric heating power P S1 , and no correction is needed.

[0170] If the system cannot maintain heat balance, specifically, if temperature drop occurs, the electric heating power is increased, and if temperature rise occurs, the electric heating power is decreased, until the system maintains heat balance, at which time the corresponding electric heating power is determined as the actual required electric heating power P S1 of the reaction equipment at the target temperature T1 to maintain the heat balance of the system. L1 This case means that the theoretical required electric heating power P L1 cannot maintain the heat balance of the system, so the theoretical required electric heating power P s1 is corrected by increasing or decreasing the electric heating power until it can maintain the heat balance of the system, at which time the electric heating power is determined as the actual required electric heating power P x .

[0171] Regarding step A3") :

[0172] A3") selects several temperature points from the reaction temperature range of the titanium concentrate acid leaching reaction as target temperatures T x , and repeats step A2) to determine the actual required electric heating power P Sx maintaining the heat balance of the system at each target temperature T x .

[0173] As in the foregoing technical solution 1, the reaction temperature range of the titanium concentrate acid leaching reaction is 115-165℃, and is preferably 125-145℃. Step A2") has selected a temperature point T1 from the above reaction temperature range, and obtained the actual required electric heating power P s1 maintaining the heat balance of the system at the temperature point T1. Step A3) is to select several other temperature points T x from the above reaction temperature range, and repeat the experiment according to the manner of step A2") to determine the actual required electric heating power P sx maintaining the heat balance of the system at each of the selected several other temperature points.

[0174] Overall, as in the foregoing technical solution 1, steps A2")-A3") are generally to 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 sx maintaining the heat balance of the system at each temperature point.

[0175] In the present application, the total number of selected temperature points in steps A2")-A3") is preferably ≥ 5. The step length between the selected temperature points is preferably 5-15℃, and can be 5℃, 10℃, or 15℃. According to the characteristics of the titanium concentrate pressure leaching reaction, for steps A2")-A3"), the present application preferably uses five temperature points of 125℃, 130℃, 135℃, 140℃, and 145℃, and obtains the actual required electric heating power P sx .

[0176] Regarding step A4") :

[0177] A4") establishes a standard curve between the temperature T1 in step A2) and the several temperatures T x in step A3) as the horizontal coordinates, and the actual required electric heating power P s1 maintaining the heat balance of the system at the temperature T1 in step A2) and the actual required electric heating power P x maintaining the heat balance of the system at the temperature T Sx in step A3) as the vertical coordinates.

[0178] As described above in technical solution 1, step A4") is to establish a standard curve between the selected temperature points in steps A2")-A3") and the actual required electric heating power P sx maintaining the heat balance of the system at each temperature point, so as to obtain the required electric heating power in the subsequent actual titanium concentrate acid leaching reaction. For example, assuming that the setting temperature of the titanium concentrate acid leaching reaction is T, the actual required electric heating power P S maintaining the heat balance of the system is calculated in advance through the standard curve, and the electric heating power is used to maintain the system balance in the subsequent actual acid leaching reaction.

[0179] In the present application, when drawing the standard curve, the temperature points can also be used as the vertical coordinates, and the electric heating power corresponding to the temperature points can be used as the horizontal coordinates. This is only different in form from the drawing method described above, but the essence is to establish a standard curve between the temperature points and the electric heating power, which also belongs to the protection scope of the present application.

[0180] [About step B"]:

[0181] B") adds titanium concentrate and acid solution into the reaction equipment, and heats the system by electricity to perform acid leaching reaction, controls the electric heating power at the actual required electric heating power corresponding to the target temperature set in the reaction equipment to maintain the heat balance of the system, and maintains the heat balance of the reaction equipment; as the acid leaching reaction proceeds, when the temperature of the reaction equipment no longer rises and remains stable, it is determined that the acid leaching reaction endpoint is reached.

[0182] In the present application, the reaction equipment is preferably a reaction kettle, in particular a pressurized reaction kettle, which is a commonly used reaction device in the current titanium concentrate acid leaching system. Preferably, the same specifications as in step A) are used.

[0183] In the present application, 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%, and can be 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, or 25%.

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

[0185] In the present application, there are two operating modes for "electricity heating acid leaching reaction", which are as follows: (1) Mode one: the actual required electric heating power P Sx is heated to the target temperature T x .(2) Mode two: first, high-power electricity is used to heat the system, and when the target temperature T x is approached, the electric heating power is reduced to the actual required electric heating power P Sx , and the target temperature T x is directly reached. In mode two, first, high-power electricity is used to heat the system, which means that the electric heating power is greater than the actual required electric heating power P Sx . The target temperature T x is preferably 15-30°C lower than the target temperature T x , i.e. T x -(15-30) °C, and can be T x -15°C, T x -16°C, T x -17°C, T x -18°C, T x -19°C, T x -20°C, T x -21°C, T x -22°C, T x -23°C, T x -24°C, T x -25°C, T x -26°C, T x -27°C, T x -28°C, or T x -29°C. x-29℃, T x -30℃. First high power energization to make the system quickly warm up, so that it can quickly approach the target temperature, and then reduce the electric heating power when it approaches the target temperature, and reduce the actual required electric heating power P Sx , continue to heat the system to the target temperature T x . The present application preferably adopts mode two, which can save process time and improve process efficiency.

[0186] In the present application, after heating to the target temperature T x , continue to heat according to the actual required electric heating power P Sx to maintain the heat balance of the system. As the titanium concentrate reacts with hydrochloric acid, the temperature of the system gradually rises, the reaction speed is faster in the early stage, the system warms up faster, and the constant electric heating power is maintained until the temperature of the reactor no longer rises (i.e. the temperature is stable), which is determined as the end point of the acid leaching reaction. In the present application, the determination criteria for the temperature no longer rising are consistent with the previous technical solution 1, which will not be repeated here. When the acid leaching reaction endpoint is reached, the heat source can be cut off, the temperature is lowered, and the product of artificial rutile is obtained.

[0187] It can be seen that the above-mentioned second titanium concentrate acid leaching reaction endpoint determination method (i.e. electric heating technical solution, referred to as technical solution 2) and the principle of the previous technical solution 1 are the same, the difference is only in the heating method of the reaction equipment, the existing technology has steam heating reactor and electric heating reactor, therefore, technical solution 1 uses steam heating, technical solution 2 uses electric heating, but the technical route of the two is the same, belongs to the same inventive concept.

[0188] The above two technical solutions of the present application adopt the same inventive concept and technical route, which is as follows: (1) for the current hydrochloric acid system reaction device (pressurized reactor), calculate the surface heat dissipation of the pressurized reactor through the Lennard-Jones equation, then verify the accuracy of the theoretical calculation through field test, and make appropriate correction; (2) supplement the surface heat dissipation of the reactor through the heating device (steam / electric heating) to maintain the reactor system as a constant temperature system; (3) as the titanium concentrate in the reactor reacts with hydrochloric acid, the heat of the system accumulates and the temperature rises, as the reaction proceeds, the reaction becomes less intense and more difficult, the reaction speed slows down, the temperature rises, until the reaction reaches the end point, the reaction no longer proceeds, and the temperature of the system no longer increases, 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 with hydrochloric acid.

[0189] The determination method of the application: the end point of the reaction of titanium concentrate and hydrochloric acid is determined by temperature change, which is simple and clear. The pressure reactor is provided with a thermometer, and no additional equipment is needed. The application is suitable for different specifications of the reactor; for different reactors, the heat dissipation of the reactor at different temperatures can be calculated according to the external surface area of the reactor, the temperature of the reaction system and the material condition; then the load test is carried out using the reactor to verify whether the theoretical calculation heat dissipation is consistent with the actual situation, and the theoretical calculation result is corrected to verify the heat dissipation of the reactor at different temperatures. According to the theoretical calculation and production verification result, the automatic control can be realized through the heating supplement system (steam amount or electric heating power) and the reactor (system) temperature detection interlocking, so that the reactor is always in a constant temperature state. The application is not only suitable for steam heating reactor, but also suitable for electric heating reactor. The application is not only suitable for Panxi titanium concentrate hydrochloric acid leaching to prepare synthetic rutile, but also suitable for other varieties of titanium concentrate to prepare synthetic rutile.

[0190] The application also provides a preparation method of synthetic rutile, which comprises the following steps: adding titanium concentrate and acid liquid into a reaction equipment, heating the system to perform acid leaching reaction, determining the end point of the acid leaching reaction, cutting off the heat source, cooling and discharging, post-treatment, and obtaining synthetic rutile product; wherein the method for determining the end point of the acid leaching reaction is the determination method in the above technical solution.

[0191] The reaction equipment, the types, specifications and dosages of the titanium concentrate and the acid liquid, the heating reaction conditions and the like are consistent with those in the above technical solution, and will not be described here.

[0192] The heating mode is steam heating or electric heating. After the reaction reaches the end point, the heat source is cut off, the reactor is depressurized, cooled and discharged, and the solid-liquid mixture is discharged. Then, the post-treatment is carried out, specifically filtering and washing, so as to obtain the synthetic rutile product.

[0193] In view of the problem that it is difficult to control the end point of the preparation of synthetic rutile by hydrochloric acid pressure leaching of Panxi titanium concentrate, through in-depth analysis of the material characteristics of titanium concentrate and the solid reaction mechanism of hydrochloric acid leaching liquid, the reaction control condition is mastered, the reaction heat release condition in the reactor is tracked to judge the reaction end point, that is, the reaction end point is determined by the temperature change of the reaction system. The method is simple and reliable, easy to implement, and reasonable through test verification. The method can be implemented on the existing equipment without additional equipment investment, and is stable in operation and easy to industrialize.

[0194] In order to further understand the application, the preferred embodiments of the application are described below in combination with examples, but it should be understood that these descriptions are only for further illustrating the features and advantages of the application, and are not limitations of the claims of the application.

[0195] Example 1

[0196] The present example is an industrial test, a 10 m 3 The industrial test of preparing synthetic rutile from Panxi ultrafine titanium concentrate by hydrochloric acid pressure leaching was carried out in a ceramic-lined steel reactor with mechanical stirring and steam heating. The leaching reaction was operated in batch mode, with 2.0-2.5 tons of titanium concentrate, 6-8 m 3 of 16%-25% dilute hydrochloric acid, and the reaction temperature 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 for the reaction equipment at the reaction temperature:

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

[0199] A2) Add 2.2 tons of quartz sand and 6.6 m 3 of 18% dilute hydrochloric acid to the reactor, detect the system temperature T0, and heat to 135°C by passing a large amount of steam, reduce the steam amount to the theoretical calculation required steam amount m L1 (calculated by formula (2)), and verify whether the system can maintain heat balance (the temperature difference is 0°C within 30 minutes, then the system maintains heat balance); it is found that the system has a temperature drop, and the steam amount is appropriately increased to 6 kg / h (i.e. 1.7 x 10 -3 kg / s), and the result can maintain the heat balance of the system, therefore, the actual required steam amount to maintain the heat balance of the system at 135°C is determined to be 6 kg / h.

[0200] A3) Maintain the temperature of the reactor and the material at 125°C, 130°C, 140°C, and 145°C respectively, and repeat the step A2) operation to determine the steam amount required to maintain the system balance at each temperature point.

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

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

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

[0204] A4) Establish a standard curve with the temperature points of steps A2)-A3) as the horizontal coordinates and the corresponding steam amounts as the vertical coordinates.

[0205] B) Add 2.2 tons of titanium concentrate and 6.6 m 3Dilute hydrochloric acid (concentration 18%), open stirring, pass a large amount of steam to heat quickly, when the system temperature reaches 115℃ (reaction temperature is 135℃, the above temperature is 20℃ lower than the reaction temperature), gradually reduce the steam amount to the required steam amount 6kg / h; with the reaction of titanium concentrate and hydrochloric acid, the system temperature gradually increases, the reaction speed is faster in the early stage, the system temperature rises faster, maintain the above constant steam amount, until the reaction kettle temperature no longer rises (i.e. the temperature is stable, the temperature difference is 0 within 3min), then it is determined that the acid leaching reaction endpoint is reached, and the leaching time is 3 hours and 28 minutes.

[0206] After reaching the reaction endpoint, cut off the steam, the reaction kettle is depressurized, cooled, and the solid-liquid mixture is discharged, filtered and washed to obtain the synthetic rutile product.

[0207] Control example:

[0208] According to the acid leaching reaction process of titanium concentrate in Example 1, the traditional time node control method (leaching time 7 hours) is used to obtain the synthetic rutile product.

[0209] The chemical composition of the synthetic rutile products obtained by the two methods is shown in Table 2.

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

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

[0212] As can be seen from the test results in Table 2, excluding sampling errors, the rutile grade obtained by the endpoint determination method of the present application is basically the same as that obtained by the traditional endpoint determination method, and the impurity elements FeO, MgO, CaO, MnO2, Al2O3 and Fe2O3 have basically the same leaching effect, which shows that when the reaction reaches the endpoint during the leaching process of titanium concentrate, with the extension of time, the impurity elements no longer react with hydrochloric acid, and the impurity element leaching rate will not improve, which also shows the accuracy of the leaching endpoint determination method of the present application, and verifies the rationality of the method determined by the present application. Compared with the prior art, the present application greatly shortens the process time, reduces the energy consumption, improves the production efficiency and reduces the production cost.

[0213] The principles and implementations of the present application are described herein with specific examples, and the above descriptions of the examples are only used to help understand the method of the present application and its core ideas, including the best mode, and also enable any person skilled in the art to practice the present application, including manufacturing and using any device or system, and implementing any combined method. It should be noted that, for those skilled in the art, some improvements and modifications can be made to the present application without departing from the principles of the present application, and these improvements and modifications also fall within the protection scope of the claims of the present application. The scope of patent protection of the present application is defined by the claims, and can include other embodiments that can be conceived by those skilled in the art. If these other embodiments have structural elements similar to the literal expressions of the claims, or if they include equivalent structural elements that are not substantially different from the literal expressions of the claims, then these other embodiments should also be included within the scope of the claims.

Claims

1. A method for determining the endpoint of an acid leaching reaction of titanium concentrate, characterized in that, Includes the following steps: 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 Q of the reaction equipment per unit time; A2) Place the simulated sample and acid solution into the reaction apparatus, monitor the system temperature T0, and introduce steam to heat to the target temperature T1, controlling the steam introduction rate to the theoretically required steam amount m. L1 To verify whether the system can maintain thermal balance; wherein, the simulated sample does not react with the acid solution; If the system can maintain heat balance, then the theoretically required amount of steam m L1 That is, the actual amount of steam m required to maintain the thermal balance of the system at the target temperature T1 is determined. S1 ; If the system cannot maintain heat balance, specifically, if a temperature drop occurs, the steam quantity is increased; if a temperature rise occurs, the steam quantity is decreased, until the system maintains heat balance. The corresponding steam quantity at this point is determined as the actual steam quantity m required by the reaction equipment to maintain heat balance at the target temperature T1. S1 ; in, Theoretical required steam quantity m L1 The result is obtained by formula (2): m L1 =Q / C×(T1–T0) Equation (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, in kg / s; Q represents the heat dissipation of the reaction equipment per unit time obtained in step A1), in 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, in K; T1 is the target temperature after steam heating, in K; A3) Select several temperature points within the reaction temperature range of the titanium concentrate acid leaching reaction as target temperatures 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 several temperatures T in step A3) x The x-axis represents the actual amount of steam (m) required to maintain the system's heat balance at temperature T1 in step A2). S1 and the temperature T in step A3) x The actual amount of steam required to maintain the heat balance of the system (m) Sx Establish a standard curve with the vertical axis as the ordinate; B) Add titanium concentrate and acid to the reaction equipment, and introduce steam to heat the system for acid leaching reaction. Control the amount of steam at the actual amount of steam required to maintain the thermal balance of the system at the target temperature set in the reaction equipment. When the temperature of the reaction equipment stops rising and remains stable as the acid leaching reaction proceeds, it is determined to be the end point of the acid leaching reaction.

2. A method for determining the endpoint of an acid leaching reaction of titanium concentrate, characterized in that, Includes the following steps: A) Determine the electrical heating power required to maintain thermal balance in the reaction equipment at the reaction temperature: A1) Theoretical calculation of the heat dissipation Q of the reaction equipment per unit time: A2") Place the simulated sample and acid solution into the reaction apparatus, monitor the system temperature T0, and heat to the target temperature T1, controlling the electric heating power to the theoretically required electric heating power P. L1 To verify whether the system can maintain thermal balance; wherein, the simulated sample does not react with the acid solution; If the system can maintain thermal balance, then the theoretically required electric heating power P L1 That is, the actual electric heating power P required to maintain the thermal balance of the system in the reaction equipment at the target temperature T1 is determined. s1 ; If the system cannot maintain thermal balance, specifically, if a temperature drop occurs, the electric heating power is increased; if a temperature rise occurs, the electric heating power is decreased, until the system maintains thermal balance. The corresponding electric heating power at this point is determined as the actual electric heating power P required by the reaction equipment to maintain thermal balance at the target temperature T1. S1 ; in, Theoretically required electric heating power P L1 The result is obtained by calculation using formula (2"): P L1 =Q-form (2"); In formula (2"): P L1 The theoretically required electric heating power (W) to maintain the thermal balance of the system at the target temperature T1; Q is the heat dissipation per unit time of the reaction equipment obtained in step A1), in W; A3") Select several temperature points within the reaction temperature range of the titanium concentrate acid leaching reaction as target temperatures 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") uses the temperature T1 in step A2) and several temperatures T in step A3). x The x-axis represents the actual electric heating power P required to maintain the system's thermal balance at temperature T1 in step A2). s1 and the temperature T in step A3) x The actual electric heating power P required to maintain the thermal balance of the system Sx Establish a standard curve with the vertical axis as the ordinate; B") Add titanium concentrate and acid to the reaction equipment, and heat the system with electricity to carry out the acid leaching reaction. Control the electric heating power at the actual electric heating power required to maintain the thermal balance of the system at the target temperature set by the reaction equipment. Maintain the thermal balance of the reaction equipment. When the temperature of the reaction equipment no longer rises and remains stable as the acid leaching reaction proceeds, 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 simulated sample is quartz sand; the acid solution is hydrochloric acid.

4. The determination method according to claim 1, characterized in that, In step A2): The operation method for heating the system to the target temperature T1 by introducing steam is as follows: first, an excess of steam is introduced to heat the system; when the temperature approaches the target temperature T1, the steam introduction rate is reduced to the theoretically required steam rate m. L1 Continue heating to the target temperature T1; The criterion for determining whether a system maintains thermal equilibrium is: the system temperature fluctuates at 0℃ within a time 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 size 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 simulated sample is quartz sand; the acid solution is hydrochloric acid.

7. The determination method according to claim 2, characterized in that, In step A2"): The operation method for heating to the target temperature T1 is as follows: first, the system is heated with high power; when it approaches the target temperature T1, the electric heating power is reduced to the theoretically required electric heating power P. L1 Continue heating to the target temperature T1; The criterion for determining whether a system maintains thermal equilibrium is: the system temperature fluctuates at 0℃ within a time 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 size between the selected temperature points is 5 to 15°C.

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

10. A method for preparing synthetic rutile, characterized in that, include: Titanium concentrate and acid were added to the reaction equipment, and the system was heated to carry out the acid leaching reaction. When the acid leaching reaction reached the endpoint, the heat source was cut off, the material was cooled and discharged, and then processed to obtain the artificial rutile product. The method for determining whether the acid leaching reaction has reached its endpoint is the method described in any one of claims 1 to 9.