Method for preparing acidolysis titaniferous solution through acidolysis of ilmenite

Abstract

The method comprises the following steps: taking a first sulfuric acid solution, adding mineral powder A into the first sulfuric acid solution according to an acid-mineral ratio of 0.4-0.55, stirring, heating, controlling the temperature, and curing, so that all ferric oxide in the mineral powder A reacts with the first sulfuric acid solution to generate a ferric sulfate solution, 16-42% ferrous oxide reacts with the first sulfuric acid solution to generate a ferrous sulfate solution, and the ferrous sulfate solution reacts with the first sulfuric acid solution to generate a ferrous sulfate solution; cooling to room temperature, filtering, washing with water to remove reactants, and drying to obtain mineral powder B; adding mineral powder B into a second sulfuric acid solution according to an acid-mineral ratio of 1.7-1.85, stirring, heating to obtain a solid-phase substance, curing, taking out the solid-phase substance, and crushing; adding water, stirring, heating and curing to obtain a titanium solution; and adding a flocculating agent to settle the titanium solution, and heating the titanium solution until the titanium solution has a supernatant liquid and a lower-layer isolate, so that the supernatant liquid is the acidolysis titanium solution. During acidolysis, iron powder and ferric iron do not need to be added for reduction, operation is easy, the prepared acidolysis titanium solution is good in stability, the iron-titanium ratio is low, cost is low, and the acidolysis degree of ilmenite is high.

Description

Technical Field

[0001] The invention relates to the field of preparation of titanyl sulfate, in particular to a method for preparing acid-hydrolyzed titanium liquid by acid-hydrolyzing ilmenite. Background Art

[0002] The acid hydrolysis of ilmenite is to add the crushed ilmenite powder into sulfuric acid to decompose the titanium dioxide and other components in the ilmenite that can react with sulfuric acid into sulfates. When water and acid are added, all soluble sulfates are dissolved in water to form a black solution, commonly known as black titanium liquid. The remaining insoluble impurities are removed by sedimentation or filtration to achieve the purpose of purification.

[0003] At present, the feeding method of industrial production acid hydrolysis is to mix the measured concentrated sulfuric acid and ilmenite in a container with mechanical stirring, and then add the mixture into the acid hydrolysis pot. Under the stirring of compressed air, the measured initiator waste acid or initiator water is added to initiate the reaction. When the temperature is low in winter, steam heating is turned on after adding the initiator liquid to initiate the main reaction. After a period of aging, water is added with the assistance of compressed air to leach the solid phase and promote the dissolution of the solid phase.

[0004] Patent CN20222220973 discloses a laboratory device for acid hydrolysis test, comprising a heating jacket, a cover and a beaker, wherein the cover is movably arranged on the heating jacket, and the beaker is placed in the heating jacket, wherein a stirring port is arranged on the top of the cover, the cover has a notch and a covering component which can cover the notch is movably arranged above the notch.

[0005] In the prior art, in order to prevent the trivalent iron from being encapsulated in the TiO 2 Inside the particles, the encapsulated trivalent iron is difficult to remove, and a reducing agent such as iron powder needs to be added to remove the trivalent iron in advance. And after the reaction is completed, frozen crystals need to be added to remove ferrous sulfate. The above process is complicated to operate, costly, and has a low acid hydrolysis rate. Therefore, it is urgent to find a method for preparing titanyl sulfate by acid hydrolysis of ilmenite with a simple process, low cost, and high degree of acid hydrolysis of ilmenite. Summary of the invention

[0006] The purpose of the present invention is to solve the problems of the prior art and provide a method for preparing titanyl sulfate by acid hydrolysis of ilmenite. The method controls the temperature and the amount of sulfuric acid added when adding sulfuric acid, so that the trivalent iron in the ilmenite reacts completely with the acid, and part of the divalent iron reacts with the acid to generate soluble iron sulfate. The soluble matter is removed by filtering, and the unreacted ilmenite is dried and then reacted with concentrated sulfuric acid to prepare an acid hydrolysis titanium solution.

[0007] In order to solve the above technical problems, the present invention provides a method for preparing acid-hydrolyzed titanium liquid by acid hydrolyzing ilmenite, which method comprises the following steps:

[0008] S1: taking a first sulfuric acid solution with a reaction concentration of 35-55% and placing it in a glass beaker, start stirring, add mineral powder A in the glass beaker at an acid-ore ratio of 0.4-0.55, stir for 10-30 minutes, raise the temperature and control the temperature at 60-100°C, and mature for 0.5-1h, so that all the iron oxide in the mineral powder A reacts with the first sulfuric acid solution to form a ferrous sulfate solution, and 16-42% of the ferrous oxide reacts with the first sulfuric acid solution to form a ferrous sulfate solution, cool to room temperature, filter, wash with water to remove the ferric sulfate solution and the ferrous sulfate solution, and dry to obtain mineral powder B;

[0009] S2: Place the second sulfuric acid solution with a reaction concentration of 80-88% in a glass beaker, start stirring, slowly add mineral powder B in the glass beaker at an acid-ore ratio of 1.7-1.85 and stir for 10-15 minutes, adjust the heating rate according to the change of the reaction temperature to obtain a solid phase, place the solid phase in an oven at 200-220°C for aging for 2-3 hours, take out the solid phase and crush it;

[0010] S3: placing the solid phase obtained in S2 in a glass beaker, adding water, stirring, heating, and ripening to completely dissolve the solid phase to obtain titanium liquid;

[0011] S4: Add a flocculant to the titanium liquid prepared in S3 to settle the titanium liquid, and heat the titanium liquid until an upper clear liquid and a lower separated product appear in the titanium liquid, wherein the upper clear liquid is the acid-hydrolyzed titanium liquid.

[0012] In a preferred embodiment of the present invention, the mineral powder A in S1 is obtained by crushing ilmenite, and the particle size of the mineral powder A is: passing through a 325 mesh sieve, and the sieve residue is 8-15%, preferably 10-12%. If the particle size of the mineral powder A is too fine, the first sulfuric acid solution reacts too violently with the mineral powder A, releasing a large amount of heat, and a boiling accident is likely to occur; if the particle size of the mineral powder A is too coarse, the mineral powder A reacts incompletely with the first sulfuric acid solution, affecting the acid hydrolysis rate of the mineral powder A.

[0013] In the present invention, the metal oxide in the mineral powder A is Fe 2 O 3 ,FeO,TiO 2 , MnO and MgO, the activation energy of each metal oxide in the mineral powder A depends on Fe 2 O 3 ,FeO,TiO 2 The order of reaction is increasing. According to the theory of chemical reaction kinetics, the activation energy determines the difficulty of the substance reaction. Therefore, the order of reaction with the first sulfuric acid solution is: Fe 2 O 3 ,FeO,TiO 2 , MnO and MgO, and controlling the reaction temperature and the concentration of the first sulfuric acid solution to make Fe 2 O 3, FeO reacts with acid first, controlling TiO 2 Does not react with acid. Add an appropriate amount of the first sulfuric acid solution and control the temperature to make Fe 2 O 3 Completely react with acid, and excess acid reacts with part of FeO. In the present invention, 16-42% of ferrous oxide reacts with the first sulfuric acid solution to generate soluble ferrous sulfate, and a part of ferrous sulfate is first removed by washing with water. Since a part of ferrous sulfate is removed first, the content of ferrous sulfate in the prepared titanium liquid is not high, and it is not necessary to remove ferrous sulfate by freezing crystallization. And the applicant has found through many experiments that by controlling 16-42% of ferrous oxide to react with sulfuric acid, ferrous sulfate can be removed without adding freezing crystallization.

[0014] Fe 2 O 3 The reaction formulas of FeO and acid are as follows:

[0015] Fe 2 O 3 +3H 2 SO 4 =Fe 2 (SO 4 ) 3 +3H 2 O

[0016] FeO+H 2 SO 4 =FeSO 4 +H 2 O

[0017] Filter and wash to remove soluble Fe 2 (SO 4 ) 3 and FeSO 4 , and dry to obtain mineral powder B.

[0018] It is judged whether all the trivalent iron in the ore powder A reacts with the first sulfuric acid solution, and whether the titanium in the ore powder A reacts with the sulfuric acid: ①Fe 3+ Detection: Take a small amount of the filtrate and add ammonium thiocyanate (NH 4 SCN), the solution was found to be blood red, indicating that there were trivalent iron ions in the filtrate. ② Detect whether titanium reacts with sulfuric acid: Take a small amount of 0.1ml of the filtrate and add 100ml of water. If there is no white turbidity, it means that TiO 2 No reaction with sulfuric acid.

[0019] In the present invention, the reaction temperature of the mineral powder A and the first sulfuric acid solution is controlled at 60-100°C, preferably 75-85°C. Too high a temperature will induce the TiO 2 react with the first sulfuric acid solution; the reaction temperature is too low, Fe 2 O3 , the reaction time of FeO and the first sulfuric acid solution is too long.

[0020] In the present invention, the reaction concentration of the first sulfuric acid solution in S1 is 35-55%, preferably 40-50%. If the concentration of the first sulfuric acid solution is too high, the TiO 2 react with the first sulfuric acid solution; the concentration of the first sulfuric acid solution is too low, Fe 2 O 3 , the reaction time of FeO and the first sulfuric acid solution is too long, and the working efficiency is low.

[0021] In a preferred embodiment of the present invention, the acid hydrolysis rate of the mineral powder A in S1 is ≥95%.

[0022] In a preferred embodiment of the present invention, the addition rate of mineral powder B in S2 is 9-15 g / min. The stirring time in S2 is 10-15 minutes, which is convenient for the mineral powder B and the second sulfuric acid solution to be fully stirred and uniformly mixed, so as to facilitate sufficient reaction in the later stage.

[0023] In a preferred embodiment of the present invention, after adding mineral powder B to the second sulfuric acid solution in S2, the temperature is raised to 120°C within 3-5 minutes, and then the heating rate is reduced to 180°C. If the temperature is raised too fast, the metal oxides in the mineral powder B will overflow, resulting in a safety accident. The method of the present invention can make the metal oxides in the mineral powder B fully react with the second sulfuric acid solution to generate a solid phase (TiOSO 4 、FeSO 4 、MnSO 4 MgSO 4 ), the reaction formula is as follows:

[0024] TiO 2 +H 2 SO 4 =TiOSO 4 +H 2 O

[0025] FeO+H 2 SO 4 =FeSO 4 +H 2 O

[0026] MnO+H 2 SO 4 =MnSO 4 +H 2 O

[0027] MgO+H 2 SO 4 =MgSO 4 +H 2 O

[0028] In the present invention, after the solid phase is generated by the reaction, the solid phase is placed in an oven at 200-220° C. and aged for 2-3 hours in order to make the second sulfuric acid solution and the mineral powder B react more fully.

[0029] In a preferred embodiment of the present invention, the method for removing the solid phase in S2 is: add 5-15 ml of deionized water along the inner wall of the glass beaker, let it stand for 5-15 minutes to allow the deionized water and the solid phase on the inner wall of the glass beaker to be completely soaked, place the glass beaker in an ultrasonic oscillator, and vibrate to peel off the solid phase from the inner wall of the glass beaker.

[0030] After the acid hydrolysis reaction solid phase is ripened, the acid hydrolysis reaction solid phase is separated from the inner wall of the glass beaker by the vibration of the ultrasonic oscillator, and it is very easy to peel off. The conventional glass beaker needs to be broken after acid hydrolysis ripening, which is a dangerous operation. The glass slag is mixed into the solid phase, which affects the sedimentation of colloidal impurities in the titanium liquid in the later stage. The present invention is simple and convenient to operate.

[0031] In a preferred embodiment of the present invention, the solid phase in S2 is crushed to less than 0.5 cm 3 Granules are convenient for later extraction.

[0032] In a preferred embodiment of the present invention, the solid phase in S3 (in the form of TiO 2 The weight ratio of titanium (calculated) to water is 1:4-5. At this ratio, a titanium liquid with a concentration of 110-130g / l can be obtained. This concentration is more conducive to the subsequent sedimentation of the titanium liquid to remove impurities.

[0033] In the present invention, during leaching in S3, the solid phase is placed in a beaker, water is added and stirred for 0.5-1h, and the temperature is raised to 70-75°C. If the temperature is too low, the solid phase is not completely leached, and if the temperature is too high, the titanium liquid will be hydrolyzed early. The aging time in S3 is 1-2 hours. If the aging time is too short, the solid phase cannot be completely dissolved, resulting in a low acid hydrolysis rate of the mineral powder.

[0034] In a preferred embodiment of the present invention, the flocculant in S4 is polyacrylamide, and the concentration of the flocculant is 300-700ppm. After adding polyacrylamide to the titanium liquid, the titanium liquid is allowed to settle, and the temperature of the titanium liquid is raised to 45-60°C, preferably 50-55°C. If the sedimentation temperature is too low, the impurities in the titanium liquid will flocculate, the sedimentation effect will be poor, and the removal of impurities in the titanium liquid will be unsatisfactory; if the sedimentation temperature is too high, it will induce early hydrolysis of the titanium liquid. The sedimentation time after adding the flocculant to the titanium liquid in S4 is 2-4 hours, preferably 3-3.5 hours. If the time is too short, the impurities cannot be completely settled, affecting the clarity of the titanium liquid. These impurities will induce early hydrolysis of the titanium liquid; if the time is too long, it will also induce hydrolysis of the titanium liquid.

[0035] In a preferred embodiment of the present invention, the concentration of the acid-decomposed titanium solution in S4 is 110-130 g / l, the F value is 1.92-2.0, and the Fe / TiO 2 : 0.23-0.33, stability ≥350ml.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] (1) The present invention controls the amount of the first sulfuric acid solution added to the mineral powder A to control the first sulfuric acid solution to react only with the Fe 2 O 3 , FeO, so that the trivalent iron in the ore powder A completely reacts with the first sulfuric acid solution to form ferric sulfate, and part of the divalent iron reacts with the first sulfuric acid solution to form ferrous sulfate, and the ferrous sulfate and ferrous sulfate are removed by washing. It is no longer necessary to add iron powder to reduce the trivalent iron during acid hydrolysis; since part of the ferrous sulfate is removed first, the ferrous sulfate content in the prepared titanium liquid is not high, and it is not necessary to remove the ferrous sulfate by freezing crystallization, which reduces the cost of the freezing crystallization process. If the trivalent iron in the ore powder A is not removed first, it is necessary to add a reducing agent iron powder to reduce the trivalent iron in the ore powder A to divalent iron to prevent the trivalent iron from being wrapped in TiO during the hydrolysis of the titanium liquid. 2 Inside the particle, this is coated with TiO 2 The trivalent iron inside the particles cannot be removed, which affects the pigment properties of the final titanium dioxide.

[0038] (2) When a glass beaker is used as a reaction container in the present invention, the solid phase is peeled off from the inner wall of the glass beaker by vibration. After the acid hydrolysis reaction solid phase is ripened, the acid hydrolysis reaction solid phase is separated from the inner wall of the glass beaker by the vibration of the ultrasonic oscillator, and it is very easy to peel off. However, the conventional glass beaker needs to be broken after acid hydrolysis ripening, which is a dangerous operation. Glass slag is mixed into the solid phase, which affects the sedimentation of colloidal impurities in the later titanium liquid. The present invention is simple and convenient to operate.

[0039] (3) In the present invention, the heating rate is adjusted according to the change of the reaction temperature to obtain a solid phase, so as to avoid safety accidents caused by the second sulfuric acid solution and the mineral powder B heating up too quickly, reacting too violently, and overflowing the reactants.

[0040] (4) By rationally adjusting the concentration of the leached titanium liquid, it is beneficial to the subsequent precipitation of titanium oxysulfate to remove impurities; rationally adjusting the reaction temperature and aging time of leaching and precipitation can avoid premature hydrolysis of the titanium liquid and facilitate the removal of precipitated impurities. DETAILED DESCRIPTION

[0041] The present invention is further described below by means of specific embodiments. The embodiments of the present invention are only used as illustrations of the present invention and do not mean that the scope of the present invention is limited thereto.

[0042] Example 1

[0043] The ilmenite powder was crushed with a small pulverizer to obtain the ore powder A. The fineness of the ore powder A was 10% after passing through a 325 mesh sieve. 200g of the ore powder was weighed. Through testing, the metal oxides in the ore powder A consisted of Fe 2 O 3 ,FeO,TiO 2 , MnO and MgO, and the contents of each oxide are 48.57%, 21.57%, 24.48%, 1.56% and 3.361% respectively. The chemical equations for the reaction of ilmenite with concentrated sulfuric acid mainly include the following reactions:

[0044] Fe 2 O 3 +3H 2 SO 4 =Fe 2 (SO 4 ) 3 +3H 2 O

[0045] FeO+H 2 SO 4 =FeSO 4 +H 2 O

[0046] TiO 2 +H 2 SO 4 =TiOSO 4 +H 2 O

[0047] MnO+H 2 SO 4 =MnSO 4 +H 2 O

[0048] MgO+H 2 SO 4 =MgSO 4 +H 2 O

[0049] According to the above chemical reaction formula, it can be concluded that Fe 2 O 3 ,FeO,TiO 2 The weight of sulfuric acid required for the reaction of MnO, MgO with sulfuric acid is 1.838, 1.361, 1.225, 1.380, and 2.45 times of their own weight, respectively. 2 O 3 , FeO (30% of which is FeO) requires 248.22g of acid, as follows:

[0050] Metal oxides <![CDATA[Fe 2 THE 3 ]]> FeO content% 21.57 24.48(30％) Acid consumption ratio 1.838 1.361 Acid-ore ratio 0.3965 0.1

[0051] Fe 2 O 3 The acid consumption is 0.3965*200=79.29g; the acid consumption of FeO is 0.1*200=20g (in order to make the ferric iron react completely with sulfuric acid, 30% of FeO reacts with acid when calculating the sulfuric acid dosage. Since a part of ferrous iron is removed first, the content of ferrous sulfate in the prepared titanium liquid is not high, and it is not necessary to remove ferrous sulfate by freezing crystallization. And the applicant has found through many experiments that controlling 16-42% of ferrous oxide to react with sulfuric acid can remove ferrous sulfate without adding freezing crystallization). Therefore, the weight of the first sulfuric acid solution added is 79.29+20=99.29g, and the weight of the first sulfuric acid solution consumed by sulfuric acid with a reaction concentration of 40% is 248.22g.

[0052] Take 248.22g of the first sulfuric acid solution with a reaction concentration of 40% and place it in a glass beaker, start stirring, add 200g of mineral powder A to the glass beaker and stir for 10 minutes, heat and control the temperature at 90°C, and mature for 1h to allow all the iron oxide in the mineral powder A to react with the first sulfuric acid solution to generate a ferrous sulfate solution, and 30% of the ferrous oxide to react with the first sulfuric acid solution to generate a ferrous sulfate solution. After cooling the above materials to room temperature, filter them, wash with 400ml of water to remove the ferric sulfate solution and the ferrous sulfate solution, and dry the materials to obtain 142.2g of mineral powder B.

[0053] The composition of mineral powder B is:

[0054] Metal oxides <![CDATA[TiO 2 ]]> FeO MgO MnO Weight of each oxide (g) 97.14 34.27 3.12 6.72 content% 68.31 24.1 2.2 4.7 Acid consumption ratio 1.225 1.361 2.45 1.38 Acid-ore ratio 0.8368 0.3280 0.0539 0.0649

[0055] F value = (weight of free acid + weight of acid bound to titanium) / TiO 2 The weight of the embodiment, the F value is 1.95;

[0056] The weight of the acid bound to titanium = 97.14*1.225 = 118.997 g, the mass of the free acid = 70.4 g;

[0057] Acid-ore ratio = (weight of free acid + acid consumption of FeO + TiO 2 Acid consumption of MnO + acid consumption of MgO) / weight of mineral powder B = 1.77; therefore, the acid consumption of mineral powder B is 251.69 g, and the weight of the second sulfuric acid solution consumed by using sulfuric acid with a reaction concentration of 83% is 303.24 g.

[0058] Take 303.24g of the second sulfuric acid solution with a reaction concentration of 83% into a glass beaker, start stirring, slowly add 142.2g of mineral powder B into the glass beaker at 14g / min, and stir for 15 minutes; place the glass beaker on an electric furnace, first adjust the frequency of the voltage regulator to 50Hz, and when the temperature reaches 120°C, adjust the voltage regulator to 20Hz, slowly heat up to 180°C to obtain a solid phase, remove the glass beaker and place it in a 200°C oven for aging for 3 hours; add 5-15ml of deionized water along the inner wall of the glass beaker, let it stand for 10 minutes, so that the deionized water and the solid phase on the inner wall of the glass beaker are completely soaked, and the glass beaker is placed in an ultrasonic oscillator for 5 minutes to vibrate and peel off the solid phase from the inner wall of the glass beaker by vibration; pour out the solid phase, and crush the solid phase to less than 0.5cm 3 Particles.

[0059] The crushed solid phase was placed in a glass beaker, 450 ml of water was added and stirred for 30 minutes, the temperature was raised to 70°C, and the solid phase was placed in a water bath for aging for 1 hour to obtain titanium liquid. The acid hydrolysis rate of the sample was 95.2%.

[0060] Add polyacrylamide at a concentration of 300ppm into the titanium liquid until large flowers and sedimentation appear in the titanium liquid. The amount of polyacrylamide added is about 15ml. Heat the titanium liquid to 45°C. After sedimentation for 2 hours, an upper clear liquid and a lower separated material appear in the titanium liquid. The upper clear liquid is the acid-hydrolyzed titanium liquid.

[0061] The indicators of sampling and testing of acid-dissolved titanium liquid are: TiO 2 :125.3g / l, F value is 1.94, Fe / TiO 2 : 0.26, stability 400ml.

[0062] Example 2

[0063] The ilmenite powder was crushed with a small pulverizer to obtain the ore powder A. The fineness of the ore powder A was 12% after passing through a 325 mesh sieve. 200g of the ore powder A was weighed. Through testing, the metal oxides in the ore powder A consisted of Fe 2 O 3 ,FeO,TiO 2 , MnO and MgO, and the contents of each oxide are 48.57%, 21.57%, 24.48%, 1.56% and 3.361% respectively. The chemical equations for the reaction of ilmenite with concentrated sulfuric acid mainly include the following reactions:

[0064] Fe 2 O 3 +3H 2 SO 4 =Fe 2 (SO 4 ) 3 +3H 2O

[0065] FeO+H 2 SO 4 =FeSO 4 +H 2 O

[0066] TiO 2 +H 2 SO 4 =TiOSO 4 +H 2 O

[0067] MnO+H 2 SO 4 =MnSO 4 +H 2 O

[0068] MgO+H 2 SO 4 =MgSO 4 +H 2 O

[0069] According to the above chemical reaction formula, it can be concluded that Fe 2 O 3 ,FeO,TiO 2 The weight of sulfuric acid required for the reaction of MnO, MgO with sulfuric acid is 1.838, 1.361, 1.225, 1.380, and 2.45 times of their own weight, respectively. 2 O 3 , FeO (including 16% FeO) requires 163.55g of acid, as follows:

[0070] Metal oxides <![CDATA[Fe 2 THE 3 ]]> FeO content% 21.57 24.48(16％) Acid consumption ratio 1.838 1.361 Acid-ore ratio 0.3965 0.0533

[0071] Fe 2 O 3 The acid consumption is 0.3965*200=79.29g; the acid consumption of FeO is 0.0533*200=10.66g (in order to make the ferric iron react completely with sulfuric acid, 16% of FeO reacts with acid when calculating the sulfuric acid dosage. Since a part of ferrous iron is removed first, the content of ferrous sulfate in the prepared titanium liquid is not high, and it is not necessary to remove ferrous sulfate by freezing crystallization. And the applicant has found through many experiments that controlling 16-42% of ferrous oxide to react with sulfuric acid can remove ferrous sulfate without adding freezing crystallization). Therefore, the weight of the first sulfuric acid solution added is 79.29+10.66=89.95g, and the weight of the first sulfuric acid solution consumed by sulfuric acid with a reaction concentration of 55% is 163.55g.

[0072] 163.55 g of the first sulfuric acid solution with a reaction concentration of 55% was placed in a glass beaker and stirred. 200 g of mineral powder A was added to the glass beaker and stirred for 30 minutes. The temperature was raised and controlled at 30° C. and aged for 0.5 h to allow all the iron oxide in the mineral powder A to react with the first sulfuric acid solution to generate a ferrous sulfate solution, and 16% of the ferrous oxide reacted with the first sulfuric acid solution to generate a ferrous sulfate solution. The above materials were cooled to room temperature and filtered, washed with 400 ml of water to remove the ferric sulfate solution and the ferrous sulfate solution, and the materials were dried to obtain 149.05 g of mineral powder B.

[0073] The composition of mineral powder B is:

[0074]

[0075]

[0076] F value = (weight of free acid + weight of acid bound to titanium) / TiO 2 The weight of the embodiment, the F value is 1.95;

[0077] The weight of the acid bound to titanium = 97.14*1.225 = 118.997 g, the mass of the free acid = 70.4 g;

[0078] Acid-ore ratio = (weight of free acid + acid consumption of FeO + TiO 2 Acid consumption of MnO + acid consumption of MgO) / weight of mineral powder B = 1.803; therefore, the acid consumption of mineral powder B is 268.73 g, and the weight of the second sulfuric acid solution consumed by using sulfuric acid with a reaction concentration of 88% is 305.38 g.

[0079] Take 305.38g of the second sulfuric acid solution with a reaction concentration of 88% in a glass beaker, start stirring, slowly add 149.05g of mineral powder B in the glass beaker at 9g / min, and stir for 10 minutes; place the glass beaker on an electric furnace, first adjust the voltage regulator frequency to 50Hz, and when the temperature reaches 120°C, adjust the voltage regulator to 20Hz, slowly heat up to 180°C to obtain a solid phase, remove the glass beaker and place it in a 200°C oven for aging for 2 hours; add 15ml of deionized water along the inner wall of the glass beaker, let it stand for 15 minutes, so that the deionized water and the solid phase on the inner wall of the glass beaker are completely soaked, and the glass beaker is placed in an ultrasonic oscillator for 5 minutes to vibrate the solid phase and the inner wall of the glass beaker by vibration; pour out the solid phase and crush the solid phase to less than 0.5cm 3 Particles.

[0080] The crushed solid phase was placed in a glass beaker, 450 ml of water was added and stirred for 60 minutes, the temperature was raised to 75°C, and the solid phase was placed in a water bath for aging for 2 hours to obtain titanium liquid. The acid hydrolysis rate of the sample was 95.6%.

[0081] Add polyacrylamide at a concentration of 300ppm into the titanium liquid until large flowers and sedimentation appear in the titanium liquid. The amount of polyacrylamide added is about 15ml. Heat the titanium liquid to 60°C. After sedimentation for 4 hours, an upper clear liquid and a lower separated material appear in the titanium liquid. The upper clear liquid is the acid-hydrolyzed titanium liquid.

[0082] The indicators of sampling and testing of acid-dissolved titanium liquid are: TiO 2 :125.3g / l, F value is 1.94, Fe / TiO 2 : 0.33, stability 400ml.

[0083] Comparative Example 1

[0084] The comparative example is a conventional acid hydrolysis method:

[0085] Use a small pulverizer to crush the ilmenite to the required fineness for acid hydrolysis of the ore powder, and weigh 200g of it. Through testing, the metal oxides in the ore powder A are Fe 2 O 3 ,FeO,TiO 2 , MnO and MgO, the contents of each oxide are 48.57%, 21.57%, 24.48%, 1.56% and 3.361% respectively. The weight of mineral powder A is 200g, and the acid consumption of the above metal oxides is:

[0086]

[0087]

[0088] Calculate the acid consumption of various metal oxides in 200g of mineral powder A when they react with 100% sulfuric acid. The acid consumption of various metal oxides in 200g of mineral powder A is 1.4093*200=281.86g.

[0089] Taking F value as 1.95, calculate the amount of 100% sulfuric acid:

[0090] The mass of the acid combined with titanium = 200 * 48.57% * 1.225 = 119 g;

[0091] F value = (mass of free acid + mass of acid bound to titanium) / TiO 2 The mass of free acid = 70.4g;

[0092] The total acid content is 281.86+70.46=352.26g;

[0093] The acid-ore ratio is 352.26 / 200=1.76; since acid needs to be added in the subsequent leaching process, the actual acid-ore ratio is adjusted lower, and the actual acid-ore ratio is 90-95% of the calculated acid-ore ratio. The actual acid-ore ratio is set to 1.65, which is convenient for adding acid during leaching. The amount of sulfuric acid required for 83% reaction concentration is: 200×1.65÷83%=397.59g;

[0094] Take 397.59g of sulfuric acid with a reaction concentration of 83% into a glass beaker, start stirring and slowly add 200g of mineral powder A. After stirring for 15 minutes, heat the glass beaker with an electric furnace to allow the main reaction to occur. Turn off the heating and place the glass beaker in an oven at 200°C for 3 hours. Take out the glass beaker, break it, and crush it to obtain a solid phase.

[0095] The crushed solid phase was placed in a glass beaker, 450 ml of water was added and stirred, 23 g of 98% sulfuric acid was added, stirring was continued for 30 min, the temperature was raised to 70° C., and the solid phase was placed in a water bath and aged for 1 hour to obtain titanium liquid.

[0096] Add iron powder to the glass beaker every 20 minutes, with 0.5g of iron powder added each time. At the same time, use a glass rod to dip the titanium liquid and use hydrogen peroxide to qualitatively detect the color of the solution until it is colorless. Add a total of 10g of iron powder; continue stirring for 30 minutes, and then qualitatively detect that the titanium liquid still has trivalent titanium. Stop the reduction and take samples to detect that the acid hydrolysis rate of the titanium liquid is 94.0%.

[0097] Add 300ppm polyacrylamide PAM to the titanium liquid until large flowers and sedimentation appear in the titanium liquid. The amount of polyacrylamide added is about 25ml. Heat the titanium liquid to 45℃. After sedimentation for 2 hours, the titanium liquid has an upper clear liquid and a lower separator. Filter out the upper clear liquid and finely filter to obtain a static titanium liquid.

[0098] The static titanium liquid is placed in a refrigerator at a temperature of 0-5°C for 24 hours to freeze the ferrous sulfate to crystallize, and the de-crystallized ferrous sulfate is filtered out to obtain the acid-hydrolyzed titanium liquid.

[0099] The detection index of sampled acid-dissolved titanium solution is: TiO 2 : 128.3g / l, F value is 1.93, Fe / TiO 2 :0.4, stability 325ml.

[0100] 1. Total titanium concentration TiO 2 g / l

[0101] The concentration of tetravalent titanium determines the relative density of titanium liquid, and also directly affects the viscosity of titanium liquid and the impurity content of titanium liquid. When other conditions of titanium liquid remain basically unchanged, the higher the concentration of tetravalent titanium, the greater the viscosity of titanium liquid, the smaller the density difference between flocculated particles and titanium liquid, the greater the sedimentation resistance, and the poorer the sedimentation effect. Therefore, the concentration of acid-hydrolyzed titanium liquid cannot be controlled too high. However, if the concentration is too low, it will increase the concentration burden of subsequent processes. The range is 100-135g / l.

[0102] 2. F value

[0103] The ratio of effective acid to total titanium content in titanium liquid is called acid ratio. Acid ratio is also called acidity coefficient, which is generally expressed by F.

[0104] In the titanium solution obtained by leaching the acid hydrolysis product, sulfuric acid mainly exists in three different forms:

[0105] (1) Sulfuric acid combined with titanium;

[0106] (2) sulfuric acid combined with other metals (mainly iron);

[0107] (3) Unbound, excess free acid.

[0108] Since it is impossible to measure the acid bound to titanium and the free acid separately, only the sum of the two can be measured, so the sum of the two is called effective acid. Effective acid = acid bound to titanium + free acid.

[0109] The F value will affect the stability of the titanium liquid, and thus affect the sedimentation effect of the titanium liquid. When the F value is high, the free acid concentration is high, the colloidal substances in the titanium liquid will be less, and the sedimentation effect will be better. When the F value is low, the colloidal substances content is high, and the sedimentation effect becomes worse.

[0110] 3. Iron-Titanium Ratio

[0111] Total iron content and total TiO in titanium liquid 2 The ratio of the content is called the iron-titanium ratio, and the formula is as follows: Total Fe content (g / l) Iron-titanium ratio = total Fe content (g / l) / total TiO 2 Content (g / l) The iron-titanium ratio has a certain influence on the particle size and structure of the hydrolyzed metatitanic acid. Therefore, in the production of titanium dioxide, especially in the production of coating titanium dioxide, the iron-titanium ratio must be controlled within a certain range. The range is 0.25-0.35.

[0112] 4. Stability of titanium liquid

[0113] Stability is also called stability. In the production of titanium dioxide, when the conditions change, the titanium liquid has a tendency to hydrolyze early and precipitate white colloidal particles. The strength of this tendency is called the stability of the titanium liquid. The characteristic that indicates the strength of this tendency is called the stability of the titanium liquid.

[0114] 5. Acid hydrolysis rate

[0115] The total amount of soluble titanium salts in the acid hydrolysis solution (as TiO 2 The total amount of titanium contained in the ilmenite (in terms of TiO 2 The percentage of total titanium content in solution (%) is called acid hydrolysis rate. Acid hydrolysis rate of total titanium content in solution (%) = (total titanium content in solution / total titanium content in ore powder) * 100.

Claims

1. A method for preparing acid-hydrolyzed titanium liquid by acid hydrolysis of ilmenite, It is characterized in that The following steps are involved: S1: taking a first sulfuric acid solution with a reaction concentration of 35-55% and placing it in a glass beaker, start stirring, add mineral powder A in the glass beaker at an acid-ore ratio of 0.4-0.55, stir for 10-30 minutes, raise the temperature and control the temperature at 60-100° C., and mature for 0.5-1h, so that all the iron oxide in the mineral powder A reacts with the first sulfuric acid solution to form a ferrous sulfate solution, and 16-42% of the ferrous oxide reacts with the first sulfuric acid solution to form a ferrous sulfate solution, cool to room temperature, filter, wash with water to remove the ferric sulfate solution and the ferrous sulfate solution, and dry to obtain mineral powder B; S2: Place the second sulfuric acid solution with a reaction concentration of 80-88% in a glass beaker, start stirring, slowly add mineral powder B in the glass beaker at an acid-ore ratio of 1.7-1.85 and stir for 10-15 minutes, adjust the heating rate according to the change of the reaction temperature to obtain a solid phase, place the solid phase in an oven at 200-220°C for aging for 2-3 hours, take out the solid phase and crush it; S3: placing the solid phase obtained in S2 in a glass beaker, adding water, stirring, heating, and ripening to completely dissolve the solid phase to obtain titanium liquid; S4: Add a flocculant to the titanium liquid prepared in S3 to settle the titanium liquid, and heat the titanium liquid until an upper clear liquid and a lower separated product appear in the titanium liquid, wherein the upper clear liquid is the acid-hydrolyzed titanium liquid.

2. The method for preparing acid-hydrolyzed titanium liquid by acid hydrolysis of ilmenite according to claim 1, It is characterized in that The mineral powder A in S1 is obtained by crushing ilmenite, and the particle size of the mineral powder A is: passing through a 325-mesh sieve, with a sieve residue of 8-15%, preferably 10-12%.

3. The method for preparing acid-hydrolyzed titanium liquid by acid hydrolysis of ilmenite according to claim 1, It is characterized in that The acid hydrolysis rate of the mineral powder A in S1 is ≥95%.

4. The method for preparing acid-hydrolyzed titanium liquid by acid hydrolyzing ilmenite according to claim 1, It is characterized in that The addition rate of the mineral powder B in S2 is 9-15 g / min. After the mineral powder B is added to the second sulfuric acid solution in S2, the temperature is raised to 120° C. in 3-5 minutes, and the heating rate is reduced to raise the temperature to 180° C.

5. The method for preparing acid-hydrolyzed titanium liquid by acid hydrolyzing ilmenite according to claim 1, It is characterized in that The method for removing the solid phase in S2 is: add 5-15 ml of deionized water along the inner wall of the glass beaker, let it stand for 5-15 minutes to allow the deionized water and the solid phase on the inner wall of the glass beaker to be completely soaked, place the glass beaker in an ultrasonic oscillator, and vibrate to peel off the solid phase from the inner wall of the glass beaker.

6. The method for preparing acid-hydrolyzed titanium liquid by acid hydrolyzing ilmenite according to claim 1, It is characterized in that The solid phase in S2 is crushed to less than 0.5 cm 3 Particles.

7. The method for preparing acid-hydrolyzed titanium liquid by acid hydrolyzing ilmenite according to claim 1, It is characterized in that The solid phase in S3 (TiO 2 The weight ratio of calcium carbonate to water is 1:4-5.

8. The method for preparing acid-hydrolyzed titanium liquid by acid hydrolyzing ilmenite according to claim 1, It is characterized in that Add water to S3 and stir for 0.5-1h, raise the temperature to 70-75°C, and mature S3 for 1-2 hours.

9. The method for preparing acid-hydrolyzed titanium liquid by acid hydrolyzing ilmenite according to claim 1, It is characterized in that The titanium liquid in S4 is heated to 45-60°C, preferably 50-55°C, and the sedimentation time of the titanium liquid in S4 is 2-4 hours, preferably 3-3.5 hours.

10. The method for preparing acid-hydrolyzed titanium liquid by acid hydrolyzing ilmenite according to claim 1, It is characterized in that The concentration of the acid-decomposed titanium solution in S4 is 110-130 g / l, the F value is 1.92-2.0, and the Fe / TiO 2 : 0.23-0.33, stability ≥350ml.

Images