RU2665759C1 - Method for processing sphene concentrate - Google Patents

Abstract

FIELD: technological processes.SUBSTANCE: invention can be used in the production of sorbents for the purification of liquid effluents from heavy metals and radionuclides, filler for paint and varnish and building materials. Method for processing sphene concentrate includes its grinding and decomposition by dilute sulfuric acid upon heating with transfer of titanium into the solution, and calcium and silicon into a solid residue. Titanium-containing solution is separated from the silicon-silicon residue, which is treated to form a filler. Salting out reagent is introduced into the titanium-containing solution in the form of sulfuric acid until a concentration of 850–950 g/l of HSOand heated to boiling. Resulting sulfuric acid liquid phase is sent to the decomposition of the concentrate. Titanium solid phase is treated with phosphoric acid at a concentration of 20–50 % HPOat a mass ratio PO:TiO, equal to 2–3.5:1. Resulting suspension is filtered with separation into a phosphate filtrate and a titanium phosphate precipitate, which is washed with water and dried. Phosphoric acid filtrate is used in the treatment of titanium solid phase.EFFECT: invention makes it possible to increase the ecological compatibility, to increase the sorption capacity of titanium phosphate, effectively.3 cl, 4 ex

Description

The invention relates to a technology for processing sphenic concentrate to produce titanium-containing products used as sorbents for the purification of liquid effluents from heavy metals and radionuclides, as well as in the production of filler for paints and construction materials.

In the chemical processing of titanium-containing concentrates, it is necessary not only to obtain a product with high properties, but also to organize processing taking into account environmental requirements with a minimum consumption of reagents and the use of liquid effluents in circulation. Existing methods for the processing of sphenic concentrate are characterized by insufficiently high sorption capacity of the obtained titanium compound, as well as the formation of a significant amount of acidic effluents. The present invention is directed to solving this problem.

A known method of processing sphene material (see Pat. 2178769 RF, IPC ⁷ C01G 23/00, C22B 3/08, 2002), including grinding the concentrate to a particle size of less than 63 microns, its decomposition with 30-50% sulfuric acid at 70-90 ° C in the presence of a fluorine ion in an amount of 0.25-1 mol / mol of titanium with the conversion of titanium into solution, and calcium and silicon into a solid residue. The titanium-containing solution is separated by filtration from the solid calcium-silicon residue and treated with 80% phosphoric acid, after which the precipitate of titanium phosphate and the liquid phase are separated. The solid calcium-silicon residue is washed with acidified water at T: W = 1: 1.3-2.6, and the washing solution is returned to the decomposition stage. The degree of extraction of titanium from the concentrate into the solution is 80-88% by TiO ₂ .

This method is not characterized by a sufficiently high degree of extraction of titanium in a titanium-containing solution. Due to the fact that the precipitate of titanium phosphate is not subjected to additional processing (washing and drying), it contains an increased amount of acidic mother liquor from which it is precipitated, which excludes the possibility of its use for purification of effluents from radionuclides and toxic metal cations. In addition, the multicomponent liquid phase, in which, in addition to sulfuric acid, impurities of fluorine and phosphate ions are present, it is impossible to use in circulation for the decomposition of the concentrate, which reduces the manufacturability and environmental friendliness of the method.

There is also known a prototype method for processing sphene concentrate (see Pat. 23233881 RF, IPC C01G 23/00, C22B 3/08 (2006.01), 2008), including grinding the concentrate to a particle size of not more than 10 microns, its decomposition 35-45 % sulfuric acid when heated to 100-110 ° C with the conversion of titanium into a solution, and calcium and silicon into a solid residue, the separation of the titanium-containing solution from the solid residue, which is treated with milk of lime to pH 7 and subjected to heat treatment at 500 ° C to obtain calcium-silicon pigment filler. A salting out reagent in the form of ammonium sulfate is introduced into the titanium-containing solution based on the deposition of not more than 85% titanium, the precipitate is separated from the sulfate liquid phase and washed with a saturated solution of ammonium sulfate to obtain a double titanium salt in the form of ammonium titanyl sulfate. The sulfate liquid phase formed after separation of the precipitate and containing ammonium sulfate, sulfuric acid and residual titanium is treated with phosphoric acid at a concentration of 50-70% and a molar ratio of Ti: P = l: 2.5-3.0 for 10-15 hours to obtain a precipitate of titanium phosphate, which is washed with diluted phosphoric acid at T: W = 1: 0.5-1.5, and then with water to ensure a pH of 4-5.5. The acid filtrate after separation of the precipitate of titanium phosphate contains ammonium sulfate, sulfuric and phosphoric acids. The sorption capacity of the resulting titanium phosphate is, mEq / g: Cs - 1.75-2.1, Sr - 1.4-1.55, Co - 0.9-1.2.

The disadvantages of this method include the multicomponent composition of the effluents in the form of a sulfate liquid phase and an acidic filtrate, which does not allow their use in circulation on the decomposition of the concentrate and the allocation of titanium phosphate. This reduces the manufacturability and environmental friendliness of the method. In addition, the known method is characterized by insufficiently high sorption capacity of the obtained titanium phosphate.

The present invention is aimed at achieving a technical result, which consists in increasing the manufacturability and environmental friendliness of the method by using monocomponent effluents in the circulation in the form of a sulfate liquid phase and a phosphate filtrate. The technical result also consists in increasing the sorption capacity of the obtained titanium phosphate.

The technical result is achieved by the fact that in the method for processing sphene concentrate, including grinding the concentrate, decomposing it with dilute sulfuric acid when heated to transfer titanium into a solution, and calcium and silicon into a solid residue, separating the titanium-containing solution from the calcium-silicon residue, processing the residue to obtain a filler, introducing a salting-out reagent into the titanium-containing solution with the formation of a sulfate liquid phase and a titanium solid phase, treatment with phosphoric acid to form a suspension sion, filtering the slurry with the separation of the acidic filtrate from the precipitate titanium phosphate and its washing with water according to the invention as a salting out agent is sulfuric acid which is introduced into the titanium-containing solution to provide a concentration of 850-950 g / l H ₂ SO ₄ and heated to boiling , the resulting sulfate liquid phase is sent to the decomposition of the concentrate, and the titanium solid phase is treated with phosphoric acid with a concentration of 20-50% H ₃ PO ₄ with a mass ratio of P ₂ O ₅ : TiO ₂ equal to 2-3.5: 1, s obtaining a suspension that filtered with separation into a phosphate filtrate and a precipitate of titanium phosphate, which, after washing, is dried.

The achievement of the technical result contributes to the fact that the drying of the precipitate of titanium phosphate is carried out at a temperature of not more than 100 ° C.

The achievement of the technical result also contributes to the fact that the phosphate filtrate is used in the processing of titanium solid phase.

The essential features of the claimed invention, which determine the scope of legal protection and are sufficient to obtain the above technical result, perform functions and relate to the result as follows.

The use of sulfuric acid as a salting out reagent, which is introduced into a titanium-containing solution to provide a concentration of 850-950 g / l H ₂ SO ₄ , creates conditions for the deposition of a solid phase with a high degree of conversion of titanium from solution to precipitate. The introduction of sulfuric acid to a concentration of less than 850 g / l H ₂ SO ₄ reduces the degree of conversion of titanium to the solid phase, and the introduction of sulfuric acid to a concentration of more than 950 g / l H ₂ SO ₄ practically does not affect the degree of conversion of titanium to the solid phase. In this case, the solid phase will contain an excess of bound sulfuric acid, which passes into the phosphate filtrate and complicates its use in circulation.

Heating the resulting solution to a boil accelerates the formation of a titanium solid phase and ensures its optimal structure, which favorably affects the separation rate during filtration.

The direction of the sulfate liquid phase in the decomposition of the concentrate increases the manufacturability and environmental friendliness of the method due to the reduction of reagent consumption.

Treatment of the titanium solid phase with phosphoric acid with a concentration of 20-50% H ₃ PO ₄ ensures the formation of a suspension with a given viscosity, which facilitates the formation of titanium phosphate in it. Treatment with phosphoric acid with a concentration of less than 20% H ₃ PO ₄ leads to a decrease in the viscosity of the suspension, which impairs the processability due to an increase in the duration of its filtration, and treatment with phosphoric acid with a concentration of more than 50% H ₃ PO ₄ increases the viscosity of the suspension and slows the formation of it titanium phosphate.

Treatment of the titanium solid phase with phosphoric acid at a mass ratio of P ₂ O ₅ : TiO ₂ equal to 2-3.5: 1 ensures the formation of a precipitate of titanium phosphate of a given composition and structure, which contributes to an increase in its sorption capacity. Treatment of the titanium phase with phosphoric acid at a mass ratio of P ₂ O ₅ : TiO ₂ less than 2: 1 does not provide the formation of a precipitate of titanium phosphate of the desired composition, which reduces the sorption capacity of the product. The mass ratio of P ₂ O ₅ : TiO ₂ more than 3.5: 1 practically does not affect the sorption capacity of the product.

Drying the precipitate of titanium phosphate after washing ensures the removal of water from the precipitate of titanium phosphate and contributes to the formation of a product structure with a high sorption capacity.

The combination of the above features is necessary and sufficient to achieve the technical result of the invention, which consists in increasing the manufacturability and environmental friendliness of the method due to the use of monocomponent wastewater in the form of a sulfate liquid phase and phosphate filtrate, as well as an increase in the sorption capacity of the resulting titanium phosphate.

In particular cases of carrying out the invention, the following operational parameters are preferred.

Drying the precipitate of titanium phosphate at a temperature of not more than 100 ° C provides the formation of titanium phosphate of a given structure. Drying the precipitate at a temperature of more than 100 ° C leads to compaction of the structure of titanium phosphate and, accordingly, to a decrease in its sorption capacity.

The use of phosphate filtrate in the processing of titanium solid phase reduces the consumption of reagent, which increases the manufacturability and environmental friendliness of the method.

The above particular features of the invention allow the method to be carried out in an optimal mode from the point of view of increasing the manufacturability and environmental friendliness of the method and increasing the sorption capacity of the resulting titanium phosphate.

The essence and advantages of the claimed method can be more clearly illustrated by the following Examples.

Example 1. Take 1 kg of sphenic concentrate containing, by weight. %: 35 TiO ₂ , 29 CaO, 28.5 SiO ₂ , the rest is mineral components, crushed to a particle size of not more than 10 μm, loaded into 3 l of 42% sulfuric acid and decomposition is carried out at a temperature of 110 ° C and stirring for 10 hours with the conversion of titanium into solution, and calcium and silicon into a solid residue. Then, the titanium-containing solution is separated by filtration from the calcium-silicon residue. The calcium-silicon residue is treated with milk of lime to pH 7 and subjected to heat treatment at a temperature of 500 ° C. The resulting calcium-silicon pigment filler in an amount of 1220 g contains 2.7% TiO ₂ and has the following properties: hiding power - 220 g / m ² , oil absorption - 63.6 g / 100 g, pH of the aqueous extract - 6.8. The degree of extraction of titanium in solution is 91.5% by TiO ₂ . Sulfuric acid is added to the resulting solution containing 320 g of TiO ₂ until a concentration of 850 g / l of H ₂ SO ₄ is obtained and heated to boiling. The resulting sulfate liquid phase is directed to the decomposition of the concentrate, and the titanium solid phase is treated with phosphoric acid with a concentration of 20% H ₃ PO ₄ at a mass ratio of P ₂ O ₅ : TiO ₂ equal to 2: 1 to obtain a suspension. The suspension is filtered with separation into a phosphate filtrate, which can be used in the treatment of the titanium solid phase, and a precipitate of titanium phosphate. The precipitate is washed with water and dried at a temperature of 100 ° C. The sorption capacity of the product, mEq / g: Cs ¹³⁷ - 2.16, Sr ⁹⁰ - 2.4, Co - 1.5.

Example 2. Take 1 kg of sphenic concentrate according to Example 1, crushed to a particle size of not more than 10 μm and loaded into 3 l of 42% sulfuric acid prepared from 2 l of sulfate liquid phase according to Example 1 and 1 l of water. Decomposition is carried out at a temperature of 110 ° C and stirring for 10 hours with the transfer of titanium into solution, and calcium and silicon into a solid residue. The titanium-containing solution is separated by filtration from the calcium-silicon residue. The solid calcium-silicon residue is treated with milk of lime to pH 7 and subjected to heat treatment at a temperature of 500 ° C. The resulting calcium-silicon pigment filler in an amount of 1220 g contains 2.7% TiO ₂ and has the following properties: hiding power - 220 g / m ² , oil absorption - 63.6 g / 100 g, pH of the aqueous extract - 6.8. The degree of extraction of titanium in solution is 91.5% by TiO ₂ . Sulfuric acid is added to the resulting solution containing 320 g of TiO ₂ until a concentration of 900 g / l of H ₂ SO ₄ is obtained and heated to boiling. The resulting sulfate liquid phase is sent to the decomposition of the concentrate, and the titanium solid phase is treated with phosphoric acid with a concentration of 35% H ₃ PO ₄ at a mass ratio of P ₂ O ₅ : TiO ₂ equal to 2.75: 1 to obtain a suspension. The suspension is filtered with separation into a phosphate filtrate, which can be used in the treatment of the titanium solid phase, and a precipitate of titanium phosphate. The precipitate is washed with water and dried at a temperature of 75 ° C. Sorption capacity of the product, mEq / g: Cs ¹³⁷ - 2.43, Sr ⁹⁰ - 2.60, Co - 1.55.

Example 3. Take 1 kg of sphenic concentrate according to Example 1, crushed to a particle size of not more than 10 microns and loaded into 3 l of 42% sulfuric acid prepared from 1.9 l of sulfate liquid phase according to Example 2 and 1.1 l of water. Decomposition is carried out at a temperature of 110 ° C and stirring for 10 hours with the transfer of titanium into solution, and calcium and silicon into a solid residue. The titanium-containing solution is separated by filtration from the calcium-silicon residue. The calcium-silicon residue is treated with milk of lime to pH 7 and subjected to heat treatment at a temperature of 500 ° C. The resulting calcium-silicon pigment filler in an amount of 1220 g contains 2.7% TiO ₂ and has the following properties: hiding power - 220 g / m ² , oil absorption - 63.6 g / 100 g, pH of the aqueous extract - 6.8. The degree of extraction of titanium in solution is 91.5% by TiO ₂ . Sulfuric acid is added to the resulting solution containing 320 g of TiO ₂ to provide a concentration of 950 g / l H ₂ SO ₄ and heated to boiling. The resulting sulfate liquid phase is directed to the decomposition of the concentrate, and the titanium solid phase is treated with phosphoric acid with a concentration of 50% H ₃ PO ₄ at a mass ratio of P ₂ O ₅ : TiO ₂ equal to 3.5: 1 to obtain a suspension. The suspension is filtered with separation into a phosphate filtrate, which can be used in the treatment of the titanium solid phase, and a precipitate of titanium phosphate. The precipitate is washed with water and dried at a temperature of 80 ° C. Sorption capacity of the product, mEq / g: Cs ¹³⁷ - 2.20, Sr ⁹⁰ - 2.36, Co - 1.24.

Example 4. Take 1 kg of sphenic concentrate according to Example 1, crushed to a particle size of not more than 10 μm and loaded into 3 l of 42% sulfuric acid prepared from 1.8 l of sulfate liquid phase according to Example 3 and 1.2 l of water. Decomposition is carried out at a temperature of 110 ° C and stirring for 10 hours with the transfer of titanium into solution, and calcium and silicon into a solid residue. The titanium-containing solution is separated by filtration from the calcium-silicon residue. The calcium-silicon residue is treated with milk of lime to pH 7 and subjected to heat treatment at a temperature of 500 ° C. The resulting calcium-silicon pigment filler in an amount of 1220 g contains 2.7% TiO ₂ and has the following properties: hiding power - 220 g / m ² , oil absorption - 63.6 g / 100 g, pH of the aqueous extract - 6.8. The degree of extraction of titanium in solution is 91.5% by TiO ₂ . Sulfuric acid is added to the resulting solution containing 320 g of TiO ₂ until a concentration of 900 g / l of H ₂ SO ₄ is obtained and heated to boiling. The resulting sulfate liquid phase is sent to the decomposition of the concentrate, and the titanium solid phase is treated with a phosphate filtrate with a concentration of 40% H ₃ P0 ₄ formed according to Example 3, with a mass ratio of P ₂ O ₅ : TiO ₂ equal to 3: 1, to obtain a suspension. The suspension is filtered with separation into a phosphate filtrate, which can be used in the treatment of the titanium solid phase, and a precipitate of titanium phosphate. The precipitate is washed with water and dried at a temperature of 75 ° C. Sorption capacity of the product, mEq / g: Cs ¹³⁷ - 2.31, Sr ⁹⁰ - 2.41, Co -1.26.

From the analysis of the above Examples it is seen that the proposed method in comparison with the prototype allows you to effectively use in circulation monocomponent effluents in the form of a sulfate liquid phase and phosphate filtrate, which increases the manufacturability and environmental friendliness of the method. The sorption capacity of titanium phosphate obtained according to the invention increases on average: by Cs ^{137 by} 1.2 times, by Sr ^{90 by} 1.7 times and by Co by 1.4 times. The proposed method can be implemented on standard equipment.

Claims (3)

1. A method of processing sphenic concentrate, including grinding the concentrate, decomposing it with dilute sulfuric acid when heated to transfer titanium into a solution, and calcium and silicon into a solid residue, separating the titanium-containing solution from the calcium-silicon residue, treating the residue to obtain a filler, introducing into the titanium-containing solution salting out reagent with the formation of a sulfate liquid phase and a titanium solid phase, treatment with phosphoric acid to form a suspension, filtering the suspension with acid separation th filtrate from the precipitate of titanium phosphate and rinsing with water, characterized in that the salting-out agent used is sulfuric acid which is introduced into the titanium-containing solution to provide a concentration of 850-950 g / l H ₂ SO ₄ and heated to the boil, with the resulting sulphate the liquid phase is directed to the decomposition of the concentrate, and the titanium solid phase is treated with phosphoric acid with a concentration of 20-50% H ₃ PO ₄ at a mass ratio of P ₂ O ₅ : TiO ₂ equal to 2-3.5: 1, to obtain a suspension, which is filtered phosphate phosphate the titrate phosphate litrate and precipitate, which are dried after washing. 2. The method according to p. 1, characterized in that the drying of the precipitate of titanium phosphate is carried out at a temperature of not more than 100 ° C. 3. The method according to p. 1, characterized in that the phosphate filtrate is used in the processing of titanium solid phase.