阅读说明：本技术 一种肥料级湿法磷酸高效脱砷的方法 (Method for efficiently removing arsenic from fertilizer-grade wet-process phosphoric acid ) 是由 胡国涛 徐颖健 杨晓健 王凤霞 刘松林 王诗瀚 李庆宇 刘世超 于 2020-07-09 设计创作，主要内容包括：本发明公开了一种肥料级湿法磷酸高效脱砷的方法,该方法利用具有靶向选择性的功能性配位新材料,通过其官能团的靶向选择性,脱除肥料级湿法磷酸中的砷杂质。具体步骤是将配位新材料与肥料级湿法磷酸按照一定比例进行混合,调节搅拌速度,控制反应时间、反应温度为,反应完成后,将反应料浆通过微孔过滤器进行过滤即得,脱砷后的肥料磷酸可以满足后续磷酸钙盐、磷酸钾盐等磷酸盐的生产需要。此方法最高可以将肥料级湿法磷酸中的砷从50ppm降低至1ppm以下,可根据后续磷酸盐产品对原料磷酸中砷含量的需求进行控制,砷的脱出率最高可达99.5%。采用该方法脱砷过程中不会产生硫化氢等有毒有害气体,该方法具有较好的环保价值。(The invention discloses a method for efficiently removing arsenic from fertilizer-grade wet-process phosphoric acid. The method comprises the specific steps of mixing a new coordination material with fertilizer-grade wet-process phosphoric acid according to a certain proportion, adjusting the stirring speed, controlling the reaction time and the reaction temperature, and filtering reaction slurry through a microporous filter after the reaction is finished, wherein the arsenic-removed fertilizer phosphoric acid can meet the production requirements of subsequent phosphates such as calcium phosphate, potassium phosphate and the like. The method can reduce the arsenic in the fertilizer-grade wet-process phosphoric acid from 50ppm to below 1ppm at most, can control the arsenic content in the raw material phosphoric acid according to the requirement of subsequent phosphate products, and has the highest arsenic removal rate of 99.5 percent. The method does not generate toxic and harmful gases such as hydrogen sulfide and the like in the dearsenification process, and has better environmental protection value.)

1. A method for efficiently removing arsenic from fertilizer-grade wet-process phosphoric acid is characterized by comprising the following steps: the method mainly comprises the following steps:

filtering the fertilizer-grade wet-process phosphoric acid through a vacuum filter for later use, mixing a coordination material and the fertilizer-grade wet-process phosphoric acid according to a certain proportion, wherein the mass ratio of the coordination material to the fertilizer-grade wet-process phosphoric acid is as follows: 1/10-1/1000, wherein the coordination material is a porous functional coordination material, the load capacity of a functional group is more than or equal to 0.9mmol/g, the content of phosphorus pentoxide in fertilizer-grade wet-process phosphoric acid is 45-48%, and the content of arsenic is 20-50 ppm;

and after the reaction is finished, filtering the reaction slurry through a microporous filter, wherein the filtered phosphoric acid is the dearsenified phosphoric acid product.

2. The method as claimed in claim 1, wherein the coordination material for dearsenification is a porous functional coordination material, and the loading capacity of the functional group is more than or equal to 0.9 mmol/g.

3. The method of claim 1, wherein the reaction stirring speed is controlled to 200 to 350 r/min.

4. The method according to claim 1, wherein the temperature during the dearsenification reaction is controlled to be 30-90 ℃.

5. The method according to claim 1, wherein the reaction time for dearsenification, i.e. the reaction time, is controlled to be 0.1-10 h.

6. The method as claimed in claim 1, wherein after the reaction is completed, the filtration is carried out by means of microfiltration, the pore size of the filter element of the microfiltration filter being less than or equal to 80 μm.

7. The method of claim 1, wherein the phosphoric acid product after arsenic removal meets the quality requirements of subsequent feed-grade and industrial-grade phosphate production on arsenic indicators.

Technical Field

The invention relates to the technical field of chemical industry, in particular to a novel method for efficiently removing arsenic from fertilizer-grade wet-process phosphoric acid.

Background

Phosphoric acid is widely used as a basic raw material for chemical industry in various fields such as medicine, chemical industry, food and the like. However, wet-process phosphoric acid cannot be applied to fields other than the chemical industry due to its high impurity content. A great deal of experimental research is carried out on purification treatment of wet-process phosphoric acid at home and abroad, wherein the chemical precipitation method is one of the most widely used methods, and the method has the advantages of simple process flow, small investment, low cost, low operation and control requirements and easy realization of industrialization. Although the content of arsenic in wet-process phosphoric acid is small, the presence of arsenic often has a great influence on the quality of subsequent phosphate products and is one of the impurities which are difficult to remove.

At present, the wet-process phosphoric acid arsenic removal method comprises the following methods: 1. removing arsenic by chemical precipitation. Na (Na)₂S can be used as a common dearsenization agent for dearsenization treatment of wet-process phosphoric acid. The principle is through Na₂S and H₃PO₄Reaction to form H₂S，H₂S in S^2-And As³⁺Formation of As₂S₃Precipitating to achieve the aim of removing arsenic. But by-product H₂S can cause environmental pollution and seriously harm the life of operators. Sodium and sulfur ions are introduced while arsenic is removed, so that the problem of new impurity pollution is brought to the deep purification of the fertilizer-grade wet-process phosphoric acid and the product quality. Meanwhile, because of factors such as small grain size, wide distribution, low solid content and the like of arsenic slag generated after arsenic removal, the filtration is relatively difficult. 2. And (4) dearsenization by a crystallization method. The crystallization method is to separate out phosphoric acid or phosphate in the form of crystals from a system, has the advantages of high efficiency, economy, small influence on the environment and the like compared with methods such as a chemical precipitation method, a solvent extraction method and the like, but has relatively complex operation,and the complete separation of the crystallized crystal and the mother liquor is difficult, and the development of the technology is restricted to a certain extent. 3. Ion exchange resin method. The ion exchange method is to treat wet-process phosphoric acid by using strong acid ion exchange resin to remove most of cationic impurities, but the regeneration difficulty of the resin is extremely high, the overall efficiency is low, the usage amount is large, and the total cost is high. 4. Electrodialysis method. The core equipment of the process is an ion exchange membrane, and impurities in the phosphoric acid solution are filtered under the stimulation of current by utilizing the selectivity of the ion exchange membrane to obtain the product. The method is still in a research stage at present, the main difficult points to be overcome are the selection of an ion exchange membrane and the influence of current density on the ion exchange process, the use environment is harsh, and the method can only be used for purifying dilute phosphoric acid at present. Has not been applied to industrial production on a large scale.

Disclosure of Invention

The invention aims to solve the technical problem of providing a novel method for efficiently removing arsenic from fertilizer-grade wet-process phosphoric acid aiming at the defects of the prior arsenic removal technology of the fertilizer-grade wet-process phosphoric acid.

The above object of the present invention is achieved by the following technical solutions:

a new method for efficiently removing arsenic from fertilizer-grade wet-process phosphoric acid is characterized in that arsenic in the phosphoric acid is captured in a targeted manner through a coordination functional group of a new coordination material, so that the effect of efficiently removing arsenic from the fertilizer-grade wet-process phosphoric acid is achieved; the method mainly comprises the following steps:

mixing a coordination material and fertilizer-grade wet-process phosphoric acid according to a certain proportion, wherein the mass proportion of the coordination material to the fertilizer-grade wet-process phosphoric acid is as follows: 1/10-1/1000, wherein the coordination material is a porous functional coordination material, the loading capacity of functional groups is more than or equal to 0.9mmol/g, and the arsenic content of the fertilizer-grade wet-process phosphoric acid is 20-50 ppm;

and after the reaction is finished, filtering the reaction slurry through a microporous filter to obtain the arsenic-removed fertilizer-grade wet-process phosphoric acid. Arsenic in the treated fertilizer-grade wet-process phosphoric acid is reduced to below 1ppn from 30ppm, and the production requirements of subsequent feed-grade and industrial-grade phosphates are met.

In the method, the coordination material adopted for dearsenization is a porous functional coordination material, and the loading capacity of the functional group is more than or equal to 0.9 mmol/g.

In the method, the reaction stirring speed is controlled to be 200-300 r/min.

In the method, the temperature in the dearsenization reaction process is controlled to be 30-90 ℃.

In the method, the dearsenization reaction time, namely the reaction time, is controlled to be 0.1-10 h.

The aperture of the filter element of the microporous filter is less than or equal to 80 mu m.

The inventor points out that: the functional coordination material of the invention has already applied for related invention patents, and the patent names are as follows: a method for manufacturing and using a hollow sphere which is filled with a porous substance and has a porous surface, and the patent number is as follows: 201710182138.1.

the invention utilizes the characteristic that the functional coordination new material has stronger affinity to small molecular impurities to stably and efficiently capture arsenic in the fertilizer-grade wet-process phosphoric acid on the coordination new material so as to achieve the effect of efficiently removing arsenic. The novel functional coordination material belongs to a high-efficiency porous material, so that the flowing of fertilizer-grade wet-process phosphoric acid is optimized, the arsenic in the wet-process purified phosphoric acid can be removed to the maximum extent by the aid of the oversized surface area, other impurities cannot be introduced while the arsenic is removed, toxic and harmful gases cannot be generated, the operation is simple and safe, the occupied space of equipment is small, and the novel functional coordination material has good economic benefits and environmental benefits. The novel material is adopted to carry out deep dearsenification on the wet-process purified phosphoric acid, related literature reports are not seen, arsenic in the fertilizer-grade wet-process phosphoric acid can be reduced to below 1ppm from 50ppm to the maximum, the control can be carried out according to the requirement of a subsequent phosphate product on the arsenic content in the raw material phosphoric acid, and the dearsenification rate of the arsenic can reach 99.5% to the maximum. The method of the invention does not generate toxic and harmful gases such as hydrogen sulfide and the like in the dearsenification process, and has better environmental protection value and better market application prospect.

Detailed Description

The present invention is further illustrated by the following specific examples, which are not intended to limit the scope of the invention.