阅读说明：本技术 一种由钛白渣制备片状磷酸铁的方法 (Method for preparing sheet iron phosphate from titanium dioxide slag ) 是由 郭举 刘美霞 隋岩峰 杨帆 史连军 刘松林 杨毅 尹健 廖高健 于 2019-12-31 设计创作，主要内容包括：本发明公开了一种由钛白渣制备片状磷酸铁的方法,它是采用水热法技术,以钛白渣、磷酸、氨水为原料,在特定反应条件下制备片状磷酸铁。本发明的方法主要包括两方面内容：一是钛白渣除杂精制高纯硫酸亚铁,二是由硫酸亚铁采用水热法制备片状磷酸铁。本发明通过原料预处理将钛白渣净化除杂得到高纯硫酸亚铁,然后和磷酸、氨水等在水热条件下反应制备磷酸铁,变废为宝,不仅解决了传统钛白粉生产企业固废处理难的环保问题,还得到了经济价值高的磷酸铁产品,因此本发明所述技术具有绿色、环保、低成本等优势,具有极大的工业应用价值。(The invention discloses a method for preparing sheet iron phosphate from titanium white slag, which adopts a hydrothermal method technology, takes the titanium white slag, phosphoric acid and ammonia water as raw materials, and prepares the sheet iron phosphate under specific reaction conditions. The method of the invention mainly comprises two aspects: firstly, the titanium white slag is purified and refined into high-purity ferrous sulfate, and secondly, the sheet iron phosphate is prepared from the ferrous sulfate by a hydrothermal method. According to the invention, the titanium white slag is purified and purified by raw material pretreatment to obtain high-purity ferrous sulfate, and then the high-purity ferrous sulfate reacts with phosphoric acid, ammonia water and the like under a hydrothermal condition to prepare the iron phosphate, so that waste is changed into valuable, the environmental protection problem that the solid waste treatment of traditional titanium white production enterprises is difficult is solved, and the iron phosphate product with high economic value is obtained, therefore, the technology disclosed by the invention has the advantages of environmental protection, low cost and the like, and has great industrial application value.)

1. A method for preparing sheet iron phosphate from titanium dioxide slag is characterized by comprising 5 process steps: are respectively as

① pretreatment of raw materials, namely refining and purifying the titanium white slag, and precipitating and removing impurity elements by adding a precipitator under certain conditions;

②, adding the refined ferrous sulfate and phosphoric acid into a hydrothermal reaction kettle according to the mass ratio of 1:1.2, then adding hydrogen peroxide with the theoretical mass of 110% required by ferrous ions to be oxidized into ferric ions, reacting for 6-10h under the hydrothermal condition of 120-180 ℃, and adjusting the pH of the reaction solution to 2.2-2.6 by using ammonia water and phosphoric acid in the reaction process;

③, standing the solution after the reaction is finished for a period of time, filtering after layering, and washing the filter cake with washing water which is 10 times of the filtrate;

④ drying at 95 deg.C for 4 h;

⑤ and dehydrating at 550 ℃ for 2h to obtain the iron phosphate product.

2. The method for preparing flaky ferric phosphate from titanium white slag as claimed in claim 1, wherein in the step of pretreating ① raw materials, the precipitant used for impurity removal and refining of titanium white slag is a prepared composite precipitant which is a mixture of ammonium fluoride and reduced iron powder, and the mass ratio of the composite precipitant is m_{Ammonium fluoride}：m_{Reduced iron powder}=3.6:1。

3. The method for preparing flaky iron phosphate from titanium white slag according to claim 1, wherein in the step of pretreating ① raw materials, impurity removal and refining are controlled under the conditions of 60 ℃ of reaction temperature, 2 hours of reaction time, 2.67% of treatment amount of precipitator in titanium white slag and Fe in reaction liquid²⁺The concentration was 1.37mol/L and the stirring speed was 300 revolutions/min.

4. The method for preparing the flaky iron phosphate from the titanium white slag according to claim 1, which is characterized in that in the step of pretreating ① raw materials, after impurity removal and refining reaction, the raw materials are filtered, washed by deionized water with the mass of three times that of a filter cake, and dried at 75 ℃ for 3 hours to obtain high-purity ferrous sulfate.

5. The method for preparing the flaky iron phosphate from the titanium white slag according to claim 1, which is characterized by comprising the following steps of: the concentration of the phosphoric acid solution is 20-30% and the concentration of the ferrous sulfate solution is 1-5% during the reaction.

Technical Field

The invention belongs to the field of material chemical industry, and particularly relates to a method for preparing sheet iron phosphate from titanium white slag.

Technical background

The titanium white slag is a solid waste byproduct generated in the production process of the sulfuric acid method titanium dioxide production technology, the main component is ferrous sulfate, and the impurity content is slightly different according to different production raw materials and technologies. China is a large titanium dioxide production country, most of the China adopts a sulfuric acid process production process, a large amount of solid waste titanium dioxide slag is generated, only a small part of the titanium dioxide slag is used for producing feed additives, water purifying agents and the like at present due to high impurity content and low utilization value, most of the titanium dioxide slag cannot be directly utilized, and the titanium dioxide slag is treated in a stockpiling mode, so that serious potential safety and environmental protection hazards are caused, and sustainable development of titanium dioxide production enterprises is hindered.

In recent years, researchers find that most impurity ions in the titanium white slag can be removed by adding a precipitator and adopting a precipitation method impurity removal process, and high-purity ferrous sulfate is obtained by refining. High-purity ferrous sulfate is a main raw material for preparing iron phosphate. With the development of new energy automobiles in China, the demand on iron phosphate is more and more increased, and the titanium white slag can provide a cheap iron source, so that the method for refining the titanium white slag and further preparing the iron phosphate has a remarkable cost advantage and is a new way for utilizing the titanium white slag.

The existing titanium white slag purification technology mainly comprises a crystallization method, a precipitation method, an adsorption method and the like. The crystallization method refers to re-mixing titanium dioxide waste residue and water according to a certain proportion, and separating and purifying to prepare battery-grade ferrous sulfate by using solubility difference under a certain condition, and the method has the defects of high energy consumption, low yield, difficult mother liquor treatment and the like; the precipitation method is characterized in that a precipitator is added to remove impurity ions in waste residues in a precipitation mode, so that battery-grade ferrous sulfate is prepared by purification, and the method has the advantages of low treatment cost, short process flow, convenience in operation and the like, and has the defects of reasonable selection of the impurity removing agent and control of process parameters; the adsorption method is a method for removing impurity ions by forming sol or micelle ions and utilizing the electro-adsorption property, and has the defects of difficult industrial application, poor stability of impurity removal effect and the like. Therefore, the titanium white slag precipitation and impurity removal technology needs to be deeply researched to obtain the high-purity ferrous sulfate.

At present, iron sources required for producing iron phosphate at home and abroad mainly comprise iron powder and various iron salts, such as ferric sulfate, ferric nitrate and the like. Ferrous sulfate is a main iron source for preparing iron phosphate due to low price, wide source and small environmental pollution. The existing iron phosphate preparation process mainly comprises a hydrothermal method, a liquid-phase precipitation method, a sol-gel method and the like. Compared with other methods, the hydrothermal method can effectively control the crystal growth process, so that the product has good shape consistency and uniform dispersion, and is often used for preparing iron phosphate products with special shapes. The iron phosphate with special morphology, such as spherical shape, rod shape and the like, can be used as a functional material in a specific field to improve the material performance, such as a catalyst and the like. Therefore, the iron phosphate with a special morphology has a large market demand.

The invention content is as follows:

the invention aims to provide a process for preparing sheet iron phosphate from titanium white slag, which not only solves the problem of solid waste treatment of the existing titanium white slag, but also creates certain economic benefit.

A method for preparing sheet iron phosphate from titanium dioxide slag comprises the following 5 process steps: are respectively as

① pretreatment of raw materials, namely refining and purifying the titanium white slag, and precipitating and removing impurity elements (such as magnesium, titanium and the like) by adding a precipitator under certain conditions;

②, adding the refined ferrous sulfate and phosphoric acid into a hydrothermal reaction kettle according to the mass ratio of 1:1.2, then adding hydrogen peroxide with the theoretical mass of 110% required by ferrous ions to be oxidized into ferric ions, reacting for 6-10h under the hydrothermal condition of 120-180 ℃, and adjusting the pH of the reaction solution to 2.2-2.6 by using ammonia water and phosphoric acid in the reaction process;

③, standing the solution after the reaction is finished for a period of time, filtering after layering, and washing the filter cake with washing water which is 10 times of the filtrate;

④ drying at 95 deg.C for 4 h;

⑤ and dehydrating at 550 ℃ for 2h to obtain the iron phosphate product.

In the method, in the step of pretreating ① raw materials, the precipitator used for impurity removal and refining of the titanium white slag is a prepared composite precipitator which is a mixture of ammonium fluoride and reduced iron powder, and the mass ratio of the composite precipitator is m_{Ammonium fluoride}：m_{Reduced iron powder}=3.6:1。

In the method, in the step of pretreating ① raw materials, impurity removal and refining are controlled under the conditions of 60 ℃ of reaction temperature, 2 hours of reaction time, 2.67 percent (mass fraction) of precipitator dosage based on titanium white slag treatment capacity and Fe in reaction liquid²⁺The concentration was 1.37mol/L and the stirring speed was 300 revolutions/min.

In the method, in the step of pretreating ① raw materials, after finishing the impurity removal and refining reaction, filtering, washing with deionized water with the mass of three times that of a filter cake, and drying at 75 ℃ for 3 hours to obtain high-purity ferrous sulfate.

In the method, the concentration of the phosphoric acid solution is 20-30% and the concentration of the ferrous sulfate solution is 1-5% during the reaction.

The invention adopts a hydrothermal method technology, takes titanium white slag, phosphoric acid and ammonia water as raw materials, and prepares flaky iron phosphate under specific reaction conditions. The titanium white slag is a byproduct of a sulfuric acid method titanium dioxide production process, the main component is ferrous sulfate, the titanium white slag is purified and purified by raw material pretreatment to obtain high-purity ferrous sulfate, and then the high-purity ferrous sulfate reacts with phosphoric acid, ammonia water and the like under a hydrothermal condition to prepare the iron phosphate, so that waste is changed into valuable, the environmental protection problem that the solid waste treatment of traditional titanium dioxide production enterprises is difficult is solved, and the iron phosphate product with high economic value is obtained.

Drawings

FIG. 1 is an SEM topography of iron phosphate of a product of example 1 of the present invention;

figure 2 is an SEM topography of the iron phosphate of the product of example 2 of the present invention.

Detailed Description