阅读说明：本技术 一种氟硅酸与碳酸钙快速反应制备高纯萤石的方法 (Method for preparing high-purity fluorite by rapid reaction of fluosilicic acid and calcium carbonate ) 是由 韩润林 隋岩 刘小兵 马宇霄 黄杰 王吉洋 于 2020-06-22 设计创作，主要内容包括：本发明提供一种氟硅酸与碳酸钙快速反应制备高纯萤石的方法,利用氟硅酸和碳酸钙的反应,通过保护剂,提高反应效率,在室温条件形成氟化钙,并通过二氧化硅与氟化钙的分离,得到高纯度的萤石粉。此外,本发明有助于大大提高尾矿萤石资源利用率,降低其处理成本,同时避免氧化硅等杂质对产品分离和提纯造成影响,方法具有较高的实用价值。(The invention provides a method for preparing high-purity fluorite by quickly reacting fluosilicic acid and calcium carbonate, which utilizes the reaction of fluosilicic acid and calcium carbonate, improves the reaction efficiency through a protective agent, forms calcium fluoride at room temperature, and obtains high-purity fluorite powder through the separation of silicon dioxide and calcium fluoride. In addition, the method is beneficial to greatly improving the utilization rate of tailing fluorite resources, reducing the treatment cost of the tailing fluorite resources, and simultaneously avoiding the influence of impurities such as silicon oxide on the separation and purification of products, and has higher practical value.)

1. A method for preparing high-purity fluorite by quickly reacting fluosilicic acid and calcium carbonate is characterized by comprising the following steps: the method comprises the following steps:

s1, uniformly mixing calcium carbonate, water and a protective agent, wherein the protective agent is a surfactant;

s2, slowly adding fluorosilicic acid solution under the condition of vigorous stirring, treating for 1-5 hours, and keeping the pH between 3-5 to complete the reaction of calcium carbonate and fluorosilicic acid;

s3 adding hydrochloric acid, stirring for 3-5min, centrifuging for multiple times, removing supernatant, drying, and collecting to obtain fluorite powder.

2. The method for preparing high-purity fluorite by quickly reacting fluosilicic acid with calcium carbonate as claimed in claim 1, wherein: the protective agent in S1 is one or more of sodium oleate, polyvinyl alcohol, cellulose acetate, sodium tartrate and sodium citrate.

3. The method for preparing high-purity fluorite by quickly reacting fluosilicic acid with calcium carbonate as claimed in claim 1, wherein: the mass ratio of the protective agent to the calcium carbonate in S1 is 0.1-3: 500.

4. The method for preparing high-purity fluorite by quickly reacting fluosilicic acid with calcium carbonate as claimed in claim 1, wherein: the mass ratio of the water to the calcium carbonate in the S1 is 1: 0.5-3.

5. A process for preparing high purity fluorite by the rapid reaction of fluorosilicic acid with calcium carbonate as claimed in any one of claims 1 to 4 wherein: the calcium carbonate is selected from tailings.

6. The method for preparing high-purity fluorite by quickly reacting fluosilicic acid with calcium carbonate according to claim 5, wherein the reaction is carried out by the following steps: the tailings are tungsten ore tailings.

Technical Field

The invention relates to the field of fluorite preparation, in particular to a method for preparing high-purity fluorite by quickly reacting fluosilicic acid and calcium carbonate.

Background

Fluorite is an important chemical raw material, and the main component is calcium fluoride. Fluorite is used as a flux in the metallurgical industry and as a raw material for producing hydrofluoric acid in the chemical industry. Fluorite deposits can be divided into single-type fluorite deposits and "associated" fluorite deposits. The main minerals of the ores in the associated fluorite deposit, such as tungsten, rare earth and the like, generate a large amount of tailings along with the mining of main ores, which not only causes pressure on environmental protection, but also loses fluorite resources.

Patent application No. 201310035036.9 discloses a synthetic method of calcium fluoride, this application obtains white carbon black and ammonium fluoride through the reaction of byproduct fluosilicic acid and ammonia, and ammonium fluoride reacts with calcium hydroxide to prepare calcium fluoride, and this method preparation process is complicated, and the impurity content in the final product of calcium fluoride that makes simultaneously is high.

In addition, the tungsten ore tailings contain a large amount of calcium fluoride, calcium carbonate and a small amount of silicon oxide. How to effectively treat tungsten ore tailings and realize the effective recovery of fluorite resources becomes an important research topic in the fields of chemical industry and environment.

The fluosilicic acid is a main byproduct for producing wet-process phosphoric acid and hydrofluoric acid, and has low price and high fluorine content. With the increasing shortage of fluorine resources, how to effectively utilize fluorine in fluosilicic acid also becomes a concern in the chemical industry. If the fluorine resources in the tailing sand and the fluosilicic acid can be effectively utilized, the method is not only beneficial to environmental protection and improvement of economic benefit, but also can solve the problem that the fluorite mineral deposit faces exhaustion.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a preparation method of fluorite with high efficiency and low cost. The invention utilizes the reaction of fluosilicic acid and calcium carbonate, improves the reaction efficiency through a protective agent, forms calcium fluoride at room temperature, and obtains high-purity fluorite powder through the separation of silicon dioxide and calcium fluoride. In addition, the method is beneficial to greatly improving the utilization rate of tailing fluorite resources, reducing the treatment cost of the tailing fluorite resources, and simultaneously avoiding the influence of impurities such as silicon oxide on the separation and purification of products, and has higher practical value.

The technical scheme of the invention is as follows:

a method for preparing high-purity fluorite by quickly reacting fluosilicic acid with calcium carbonate comprises the following steps:

s1, uniformly mixing calcium carbonate, water and a protective agent, wherein the protective agent is a surfactant;

s2, slowly adding fluorosilicic acid solution under the condition of vigorous stirring, treating for 1-5 hours, and keeping the pH between 3-5 to complete the reaction of calcium carbonate and fluorosilicic acid;

and (3) after the reaction of S3, adding hydrochloric acid, stirring for 3-5min, centrifuging for many times, removing supernatant, drying and collecting, wherein the obtained off-white powder is fluorite powder, and the content of calcium fluoride is more than 93%, the content of calcium carbonate is less than 5%, and the content of silicon oxide is less than 1%.

The calcium carbonate involved in the invention is pure calcium carbonate or is selected from tailings containing calcium carbonate.

The chemical reaction equation of calcium carbonate and fluosilicic acid in S2 is as follows:

3CaCO₃+H₂SiF₆=3CaF₂↓+SiO₂+3CO₂↑+H₂O

preferably, the protective agent in S1 is one or more of sodium oleate, polyvinyl alcohol, cellulose acetate, sodium tartrate and sodium citrate.

Preferably, the mass ratio of the protective agent to the calcium carbonate in S1 is 0.1-3: 500.

Preferably, the mass ratio of the water to the calcium carbonate in S1 is 1: 0.5-3.

In order to improve the resource reuse of tailings, it is preferred that the calcium carbonate is selected from tailings; furthermore, the tailings are tungsten ore tailings, and the obtained fluorite contains more than 93% of calcium fluoride, less than 5% of calcium carbonate and less than 1% of silicon oxide.

The mass fraction of the fluorosilicic acid solution in S2 is preferably 30-50%.

Preferably, 3 to 10 mass percent of hydrochloric acid is added into S3, and the volume of the hydrochloric acid is 20 ml.

The method has the advantages of simple process flow, small using amount of the used protective agent, good dispersion of calcium carbonate, avoidance of the generated calcium fluoride from inhibiting the reaction to continue, and improvement of reaction efficiency, thereby obtaining high-purity fluorite in a short time, wherein the content of the calcium fluoride in the fluorite reaches 93 percent or more, and the problem of separation of silicon oxide, silicic acid and calcium fluoride generated in the reaction process can be solved. In addition, the recovery of calcium fluoride resources in the tailings can be realized. The fluosilicic acid used is a byproduct in the phosphorus chemical industry or the hydrofluoric acid industry, and has low price and high effective fluorine content. The economic benefit and the social benefit are obvious.

Detailed Description

The following further describes the specific embodiments of the present invention in combination with the technical solutions.