Purification process for rutile titanium dioxide

Abstract

The invention discloses a purification process for rutile type titanium dioxide. The purification process comprises the following steps: S1, drying ilmenite, grinding and sieving; s2, adding a hydrochloric acid solution into the sieved ilmenite, and stirring for acidolysis to obtain an acidolysis solution; s3, the acidolysis solution is filtered and frozen, sodium chlorate is added to serve as a water phase after filtration removal, the water phase is added into the first extraction oil phase and then stirred, and the water phase obtained after extraction is collected and continues to be added into the second reverse extraction oil phase to be stirred; s4, adding the extracted oil phase into a hydrochloric acid solution for reverse extraction, finally adding deionized water, heating for hydrolysis to obtain a hydrolyzed titaniferous solution, filtering, collecting precipitates, and washing; and S5, weighing the precipitate, uniformly mixing with TiC powder, putting into a corundum crucible, heating to a preset temperature through microwaves, calcining, preserving heat, cooling to room temperature, and collecting a calcined product, thereby obtaining the high-purity rutile type titanium dioxide. The method has the advantages that the low-grade ilmenite can be used as the raw material, and the purity of the final product is 99.7% or above.

Description

Technical Field

[0001] The invention relates to the technical field of rutile titanium dioxide preparation, and in particular to a purification process for rutile titanium dioxide. Background Art

[0002] Titanium dioxide (TiO2) is an important inorganic chemical product and is used in industries such as coatings, inks, papermaking, plastics, rubber, chemical fibers, and ceramics.

[0003] The common industrial production methods of titanium dioxide are sulfuric acid method and chlorination method. The sulfuric acid method is to use sulfuric acid to hydrolyze titanium-containing minerals to obtain titanium sulfate solution, which is purified and hydrolyzed to obtain hydrated titanium dioxide precipitation, and then enters the brick kiln for roasting to produce titanium dioxide pigment products. It is a non-continuous production process with a complex process flow, requiring about 20 steps, and discharging a lot of waste, especially the hydrolysis filtrate contains a large amount of iron sulfate and waste sulfuric acid, which needs to be neutralized with slaked lime to form titanium gypsum, consuming a lot of resources and generating a lot of waste. The chlorination process is to react ilmenite, high-titanium slag, artificial rutile or natural rutile with chlorine to produce titanium tetrachloride, which is then purified by distillation and then subjected to gas-phase oxidation at temperatures above 1000°C. Titanium dioxide is then obtained through gas-solid separation. This process is a huge test for the strength, heat resistance and corrosion resistance of the materials used. Therefore, so far, key technologies and key materials have been almost monopolized by foreign countries. In addition, this process has high requirements for calcium, magnesium and other raw materials. However, more than 90% of my country's titanium resources are concentrated in vanadium-titanium magnetite in Panzhihua and Xichang, Sichuan. Due to the high calcium and magnesium content in the titanium ore in the Panzhihua area, it is difficult to use it as chloride titanium dioxide and requires large-scale imports.

[0004] The purity of rutile titanium dioxide prepared by the existing scheme is not high and contains relatively more impurities. Summary of the invention

[0005] The purpose of the present invention is to provide a purification process for rutile titanium dioxide, which can use low-grade ilmenite as a raw material, and the purity of the final product is above 99.7%. It can be used to produce high-quality titanium dioxide for the coating industry, cosmetics industry, papermaking industry, etc., to meet the market demand for high-end titanium dioxide in my country.

[0006] The above technical objectives of the present invention are achieved through the following technical solutions: A purification process for rutile titanium dioxide, characterized in that it comprises the following steps: S1, drying, grinding and sieving the ilmenite; S2, adding hydrochloric acid solution to the screened ilmenite and stirring to perform acid hydrolysis to obtain an acid hydrolyzed solution; S3, filtering the acid hydrolyzate and freezing it, filtering and removing the precipitate, adding the oxidizing agent sodium chlorate as the water phase, adding it to the first extraction oil phase and stirring it, collecting the water phase after the extraction is completed and continuing to add it to the second stripping oil phase and stirring it; S4, collecting the oil phase after extraction, adding hydrochloric acid solution for stripping, and finally adding deionized water and heating to hydrolyze to obtain hydrolyzed titanium liquid, filtering and collecting the precipitate, and then washing; S5, weighing the precipitate and TiC powder, mixing them thoroughly and evenly, and then loading them into a corundum crucible, and then putting them into a microwave reaction chamber, heating them to a preset temperature by microwave, calcining them, keeping them warm for a period of time, cooling them to room temperature, collecting the calcined products, and obtaining high-purity rutile titanium dioxide.

[0007] Preferably, the mesh size of the sieve in S1 is 200 meshes.

[0008] Preferably, in S2, the stirring speed is 500-700 r / min, the reaction time is 3-5 h, the reaction temperature is 80-90° C., the mass ratio of mineral acid is 1:3-5, and the concentration of hydrochloric acid is 10 mol / L.

[0009] Preferably, the amount of sodium chlorate added as the oxidant in S3 is 5% of the mass of the acidolysis solution after the precipitate is filtered and removed.

[0010] Preferably, the first extraction oil phase in S3 comprises 25% by volume of the first extraction agent, 25% by volume of octanol and 50% by volume of kerosene, the first extraction agent is N235, and the volume ratio of the first extraction oil phase to the aqueous phase is 3-2:1.

[0011] Preferably, the second extraction oil phase in S3 comprises 40% by volume of the second extraction agent, 20% by volume of octanol and 40% by volume of kerosene, the first extraction agent is N235, and the volume ratio of the first extraction oil phase to the aqueous phase is 3-2:1.

[0012] Preferably, the concentration of the hydrochloric acid solution in S4 is 4 mol / L, the hydrolysis reaction temperature is 100-105° C., and the hydrolysis time is 5-7 h.

[0013] Preferably, the washing method in S5 is specifically as follows: first washing once with a 1.0 mol / L NaOH solution, then acid washing twice with a 1.0 mol / L HCl solution, and then washing twice with distilled water.

[0014] Preferably, the amount of TiC powder added to the S6 is 10% to 15% of the precipitate mass, the microwave heating power is 2.5 kW, the calcination temperature is 1000 to 1030° C., the calcination time is 50 to 80 min, and the insulation time is 15 to 20 min.

[0015] In summary, the present invention can effectively improve the purity of the final rutile titanium dioxide product by secondary extraction and subsequent stripping, and then microwave calcining the hydrolysis precipitate. Microwave radiation and TiC incorporation can effectively reduce the phase change temperature point, and the sintering phenomenon is significantly improved, which is conducive to the generation of rutile titanium dioxide products with uniform size. The purity of the final product can reach above 99.7%. DETAILED DESCRIPTION

[0016] The specific implementation modes of the present invention are further described below, and these embodiments do not constitute a limitation of the present invention. Example 1

[0017] A purification process for rutile titanium dioxide comprises the following steps: S1, drying the ilmenite, grinding it and sieving it, and the mesh number of the sieving screen is 200 meshes.

[0018] S2, adding hydrochloric acid solution to the screened ilmenite and stirring for acid hydrolysis to obtain an acid hydrolyzate, the stirring speed is 500r / min, the reaction time is 3h, the reaction temperature is 80°C, the mineral acid mass ratio is 1:3, and the hydrochloric acid concentration is 10mol / L.

[0019] S3, the acid hydrolyzate is filtered and then frozen, the precipitate is filtered and removed, and then 5% of the oxidant sodium chlorate is added as the water phase, which is added to the first extraction oil phase and stirred, the water phase after extraction is collected and continued to be added to the second stripping oil phase for stirring, the first extraction oil phase includes 25% by volume of the first extractant, 25% by volume of octanol and 50% by volume of kerosene, the first extractant is N235, and the volume ratio of the first extraction oil phase to the water phase is 3:1, the second extraction oil phase includes 40% by volume of the second extractant, 20% by volume of octanol and 40% by volume of kerosene, the first extractant is N235, and the volume ratio of the first extraction oil phase to the water phase is 3:1.

[0020] S4, collecting the oil phase after extraction, adding hydrochloric acid solution to reverse extraction, and finally adding deionized water and heating to hydrolyze to obtain hydrolyzed titanium liquid, the concentration of the hydrochloric acid solution is 4 mol / L, the hydrolysis reaction temperature is 100°C, and the hydrolysis time is 5 h. Filter and collect the precipitate and wash it, first washing it once with 1.0 mol / L NaOH solution, then repeating the acid washing twice with 1.0 mol / L HCl, and then repeating the washing twice with distilled water.

[0021] S5, weigh the precipitate and TiC powder, mix them thoroughly and evenly, put them into a corundum crucible, and then put them into a microwave reaction chamber, heat them to a preset temperature of 1000°C by 2.5kW microwave, calcine them for 50 minutes, keep them warm for 15 minutes, cool them to room temperature, collect the calcined products, and add TiC powder in an amount of 10% of the mass of the precipitate, so as to obtain high-purity rutile titanium dioxide with a purity of 99.9%. Example 2

[0022] A purification process for rutile titanium dioxide comprises the following steps: S1, drying the ilmenite, grinding it and sieving it, and the mesh number of the sieving screen is 200 meshes.

[0023] S2, adding hydrochloric acid solution to the screened ilmenite and stirring for acid hydrolysis to obtain an acid hydrolyzate, the stirring speed is 700r / min, the reaction time is 3h, the reaction temperature is 80~90℃, the mineral acid mass ratio is 1:4, and the hydrochloric acid concentration is 10mol / L.

[0024] S3, filtering the acid hydrolyzate and freezing it, filtering and removing the precipitate, adding 5% of the oxidant sodium chlorate as the water phase, adding it to the first extraction oil phase and stirring it, collecting the water phase after extraction and continuing to add it to the second stripping oil phase for stirring, the first extraction oil phase includes 25% by volume of the first extractant, 25% by volume of octanol and 50% by volume of kerosene, the first extractant is N235, and the volume ratio of the first extraction oil phase to the water phase is 2:1, the second extraction oil phase includes 40% by volume of the second extractant, 20% by volume of octanol and 40% by volume of kerosene, the first extractant is N235, and the volume ratio of the first extraction oil phase to the water phase is 2:1.

[0025] S4, collecting the oil phase after extraction, adding hydrochloric acid solution to reverse extraction, and finally adding deionized water and heating to hydrolyze to obtain hydrolyzed titanium liquid, the concentration of the hydrochloric acid solution is 4 mol / L, the hydrolysis reaction temperature is 100°C, and the hydrolysis time is 7 h. Filter and collect the precipitate and wash it, first washing it once with 1.0 mol / L NaOH solution, then repeating the acid washing twice with 1.0 mol / L HCl, and then repeating the washing twice with distilled water.

[0026] S5, weigh the precipitate and TiC powder, mix them thoroughly and evenly, put them into a corundum crucible, and then put them into a microwave reaction chamber, heat them to a preset temperature of 1010°C by 2.5kW microwave, calcine them for 60 minutes, keep them warm for 20 minutes, cool them to room temperature, collect the calcined products, and add TiC powder in an amount of 12% of the mass of the precipitate, so as to obtain high-purity rutile titanium dioxide with a purity of 99.8%. Example 3

[0027] A purification process for rutile titanium dioxide comprises the following steps: S1, drying the ilmenite, grinding it and sieving it, and the mesh number of the sieving screen is 200 meshes.

[0028] S2, adding hydrochloric acid solution to the screened ilmenite and stirring for acid hydrolysis to obtain an acid hydrolyzate, the stirring speed is 600r / min, the reaction time is 4h, the reaction temperature is 80~90℃, the mineral acid mass ratio is 1:4, and the hydrochloric acid concentration is 10mol / L.

[0029] S3, filtering the acid hydrolyzate and freezing it, filtering and removing the precipitate, adding 5% of the oxidant sodium chlorate as the water phase, adding it to the first extraction oil phase and stirring it, collecting the water phase after extraction and continuing to add it to the second stripping oil phase for stirring, the first extraction oil phase includes 25% by volume of the first extractant, 25% by volume of octanol and 50% by volume of kerosene, the first extractant is N235, and the volume ratio of the first extraction oil phase to the water phase is 2:1, the second extraction oil phase includes 40% by volume of the second extractant, 20% by volume of octanol and 40% by volume of kerosene, the first extractant is N235, and the volume ratio of the first extraction oil phase to the water phase is 2:1.

[0030] S4, collecting the oil phase after extraction, adding hydrochloric acid solution for reverse extraction, and finally adding deionized water and heating for hydrolysis to obtain hydrolyzed titanium liquid, the concentration of the hydrochloric acid solution is 4 mol / L, the hydrolysis reaction temperature is 103°C, and the hydrolysis time is 6 h. Filter and collect the precipitate and wash it, first washing it once with 1.0 mol / L NaOH solution, then repeating the acid washing twice with 1.0 mol / L HCl, and then repeating the washing twice with distilled water.

[0031] S5, weigh the precipitate and TiC powder, mix them thoroughly and evenly, put them into a corundum crucible, and then put them into a microwave reaction chamber, heat them to a preset temperature of 1020°C by 2.5kW microwave, calcine them for 70 minutes, keep them warm for 20 minutes, cool them to room temperature, collect the calcined products, and add TiC powder in an amount of 13% of the mass of the precipitate, so as to obtain high-purity rutile titanium dioxide with a purity of 99.7%. Example 4

[0032] A purification process for rutile titanium dioxide comprises the following steps: S1, drying the ilmenite, grinding it and sieving it, and the mesh number of the sieving screen is 200 meshes.

[0033] S2, adding hydrochloric acid solution to the screened ilmenite and stirring for acid hydrolysis to obtain an acid hydrolyzate, the stirring speed is 700r / min, the reaction time is 5h, the reaction temperature is 90°C, the mineral acid mass ratio is 1:5, and the hydrochloric acid concentration is 10mol / L.

[0034] S3, filtering the acid hydrolyzate and freezing it, filtering and removing the precipitate, adding 5% of the oxidant sodium chlorate as the water phase, adding it to the first extraction oil phase and stirring it, collecting the water phase after extraction and continuing to add it to the second stripping oil phase for stirring, the first extraction oil phase includes 25% by volume of the first extractant, 25% by volume of octanol and 50% by volume of kerosene, the first extractant is N235, and the volume ratio of the first extraction oil phase to the water phase is 2:1, the second extraction oil phase includes 40% by volume of the second extractant, 20% by volume of octanol and 40% by volume of kerosene, the first extractant is N235, and the volume ratio of the first extraction oil phase to the water phase is 2:1.

[0035] S4, collecting the oil phase after extraction, adding hydrochloric acid solution to reverse extraction, finally adding deionized water and heating to hydrolyze to obtain hydrolyzed titanium liquid, the concentration of hydrochloric acid solution is 4 mol / L, the hydrolysis reaction temperature is 105°C, the hydrolysis time is 7h, filtering and collecting the precipitate and washing it, first washing it once with 1.0 mol / L NaOH solution, then repeating the acid washing twice with 1.0 mol / L HCl, and then repeating the washing twice with distilled water.

[0036] S5, weigh the precipitate and TiC powder, mix them thoroughly and evenly, put them into a corundum crucible, and then put them into a microwave reaction chamber, heat them to a preset temperature of 1030°C by 2.5kW microwave, calcine for 80 minutes, keep warm for 15 minutes, cool to room temperature, collect the calcined product, the amount of TiC powder added is 15% of the mass of the precipitate, and high-purity rutile titanium dioxide is obtained, and the purity is 99.8%.

[0037] The present invention can effectively improve the purity of the final rutile titanium dioxide product by secondary extraction and subsequent stripping, and then microwave calcining the hydrolysis precipitate. Microwave radiation and TiC incorporation can effectively reduce the phase change temperature point, and the sintering phenomenon is significantly improved, which is conducive to the generation of rutile titanium dioxide products with uniform size. The purity of the final product can reach above 99.7%.

[0038] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art may make various modifications or equivalent substitutions to the present invention within the essence and protection scope of the present invention, and such modifications or equivalent substitutions should also be deemed to fall within the protection scope of the technical solution of the present invention.

Claims

1. A purification process for rutile titanium dioxide, characterized in that: The steps include: S1, drying, grinding and sieving the ilmenite; S2, adding hydrochloric acid solution to the screened ilmenite and stirring to perform acid hydrolysis to obtain an acid hydrolyzed solution; S3, filtering the acid hydrolyzate and freezing it, filtering and removing the precipitate, adding the oxidizing agent sodium chlorate as the water phase, adding it to the first extraction oil phase and stirring it, collecting the water phase after the extraction is completed and continuing to add it to the second stripping oil phase and stirring it; S4, collecting the oil phase after extraction, adding hydrochloric acid solution for stripping, and finally adding deionized water and heating to hydrolyze to obtain hydrolyzed titanium liquid, filtering and collecting the precipitate, and then washing; S5, weighing the precipitate and TiC powder, mixing them thoroughly and evenly, and then loading them into a corundum crucible, and then putting them into a microwave reaction chamber, heating them to a preset temperature by microwave, calcining them, keeping them warm for a period of time, cooling them to room temperature, collecting the calcined products, and obtaining high-purity rutile titanium dioxide.

2. A purification process for rutile titanium dioxide according to claim 1, characterized in that: The mesh number of the sieve in S1 is 200 meshes.

3. A purification process for rutile titanium dioxide according to claim 1, characterized in that: In the S2, the stirring speed is 500-700 r / min, the reaction time is 3-5 h, the reaction temperature is 80-90° C., the mass ratio of mineral acid is 1:3-5, and the hydrochloric acid concentration is 10 mol / L.

4. A purification process for rutile titanium dioxide according to claim 1, characterized in that: The amount of sodium chlorate added as the oxidant in S3 is 5% of the mass of the acidolysis solution after the precipitate is filtered and removed.

5. A purification process for rutile titanium dioxide according to claim 1, characterized in that: The first extraction oil phase in S3 includes 25% by volume of the first extraction agent, 25% by volume of octanol and 50% by volume of kerosene, the first extraction agent is N235, and the volume ratio of the first extraction oil phase to the water phase is 3-2:

1.

6. A purification process for rutile titanium dioxide according to claim 1, characterized in that: The second extraction oil phase in S3 includes 40% by volume of the second extraction agent, 20% by volume of octanol and 40% by volume of kerosene, the first extraction agent is N235, and the volume ratio of the first extraction oil phase to the water phase is 3-2:

1.

7. A purification process for rutile titanium dioxide according to claim 1, characterized in that: The concentration of the hydrochloric acid solution in the S4 is 4 mol / L, the hydrolysis reaction temperature is 100-105° C., and the hydrolysis time is 5-7 h.

8. A purification process for rutile titanium dioxide according to claim 1, characterized in that: The washing method in S5 is specifically as follows: first washing once with a 1.0 mol / L NaOH solution, then acid washing twice with a 1.0 mol / L HCl solution, and then washing twice with distilled water.

9. A purification process for rutile titanium dioxide according to claim 1, characterized in that: The amount of TiC powder added to the S6 is 10% to 15% of the precipitate mass, the microwave heating power is 2.5 kW, the calcination temperature is 1000 to 1030° C., the calcination time is 50 to 80 min, and the insulation time is 15 to 20 min.