阅读说明：本技术 一种含氟废水制取氟硅酸钾的方法 (Method for preparing potassium fluosilicate from fluorine-containing wastewater ) 是由 杨英春 曹玉宽 于 2020-07-07 设计创作，主要内容包括：本发明公开了含氟废水利用技术领域的一种含氟废水制取氟硅酸钾的方法,包括以下步骤：(1)将氯化钾固体颗粒和水输送至溶解槽中,搅拌后得到氯化钾饱和溶液；(2)将含氟废水打入搅拌槽内,并向搅拌槽内投入二氧化硅,得到含氟硅酸的溶液；(3)将含氟硅酸的溶液利用真空泵予以抽滤,得到二氧化硅滤饼和滤液；(4)将氯化钾溶液和滤液注入反应器内,控制反应温度为45-55℃,得到含氟硅酸钾的液体；(5)对含氟硅酸钾的液体进行过滤干燥,得到氟硅酸钾；本发明通过加入二氧化硅,二氧化硅与氟化氢反应生成氟硅酸,氟硅酸与氯化钾反应生成氟硅酸钾,本发明对含氟废水中的氢氟酸和氟硅酸都有良好的利用,避免了资源的浪费,有利于提高经济效益。(The invention discloses a method for preparing potassium fluosilicate from fluorine-containing wastewater, which belongs to the technical field of fluorine-containing wastewater utilization and comprises the following steps: (1) conveying the potassium chloride solid particles and water into a dissolving tank, and stirring to obtain a potassium chloride saturated solution; (2) pouring fluorine-containing wastewater into a stirring tank, and adding silicon dioxide into the stirring tank to obtain a solution containing fluorine silicic acid; (3) carrying out suction filtration on the solution containing the fluosilicic acid by using a vacuum pump to obtain a silicon dioxide filter cake and filtrate; (4) injecting the potassium chloride solution and the filtrate into a reactor, and controlling the reaction temperature to be 45-55 ℃ to obtain liquid containing fluorine potassium silicate; (5) filtering and drying the liquid containing the fluorine potassium silicate to obtain potassium fluosilicate; according to the invention, silicon dioxide is added, the silicon dioxide reacts with hydrogen fluoride to generate fluosilicic acid, and the fluosilicic acid reacts with potassium chloride to generate potassium fluosilicate.)

1. A method for preparing potassium fluosilicate from fluorine-containing wastewater is characterized by comprising the following steps:

(1) conveying the potassium chloride solid particles and water into a dissolving tank, and stirring for 10-12min to obtain a potassium chloride saturated solution;

(2) pumping the fluorine-containing wastewater into a stirring tank, adding silicon dioxide into the stirring tank, stirring at the rotating speed of 300-500r/min for 10-15min, and standing for 25-35min to obtain a solution containing fluorine silicic acid;

(3) carrying out suction filtration on the solution containing the fluosilicic acid by using a vacuum pump to obtain a silicon dioxide filter cake and filtrate;

(4) injecting the potassium chloride solution and the filtrate into a reactor, controlling the reaction temperature to be 45-55 ℃, stirring for 15-20min at the rotating speed of 1000-1500r/min, and standing for 1-2h to obtain liquid containing fluorine potassium silicate;

(5) and filtering and drying the liquid containing the fluorine potassium silicate to obtain the potassium fluosilicate.

2. The method for preparing potassium fluosilicate from fluorine-containing wastewater according to claim 1, wherein the stirring temperature in the step (1) is 25-30 ℃.

3. The method for preparing potassium fluosilicate from fluorine-containing wastewater as claimed in claim 1, wherein the reaction temperature in the step (2) is 48-52 ℃, the rotation speed is 1200-1400r/min, the stirring time is 16-18min, and the standing time is 1.4-1.8 h.

4. The method for preparing potassium fluosilicate from fluorine-containing wastewater according to claim 3, wherein the reaction temperature in the step (2) is 50 ℃, the rotation speed is 1300r/min, the stirring time is 17min, and the standing time is 1.5 h.

5. The method for preparing potassium fluosilicate from fluorine-containing wastewater according to claim 1, wherein the silica filter cake in the step (3) can be put into the stirring tank again for recycling.

6. The method for preparing potassium fluosilicate from fluorine-containing wastewater as claimed in claim 1, wherein the filtrate obtained in the step (5) is neutralized by adding lime.

Technical Field

The invention relates to the technical field of fluorine-containing wastewater utilization, in particular to a method for preparing potassium fluosilicate from fluorine-containing wastewater.

Background

Potassium fluosilicate, white crystal or powder. No odor and no taste. Relative density of hexagonal crystal 3.08; cubic system crystal relative density 2.665(17 ℃ C.). Is slightly acidic. It has hygroscopic property. Is slightly soluble in water. It is soluble in hydrochloric acid and its solubility increases slightly with increasing temperature. Is insoluble in alcohol. Hydrolyzing in hot water to form potassium fluoride, hydrogen fluoride and silicic acid. Decomposing into potassium fluoride and silicon tetrafluoride when burning. Is toxic. Is commonly used as an insecticide for wood preservation, ceramic manufacture, aluminum and magnesium smelting, agriculture, optical glass manufacture, synthetic mica, porcelain glaze manufacture and the like. The waste water produced in the production of aluminum fluoride by a dry method and aluminum fluoride by a fluosilicic acid method contains hydrofluoric acid, fluosilicic acid and aluminum ions, and because both the two kinds of acid contain fluorine elements, the on-site discharge can cause serious environmental pollution and resource waste.

Disclosure of Invention

The invention aims to provide a method for preparing potassium fluosilicate from fluorine-containing wastewater, which aims to solve the problems in the background technology.

In order to realize the purpose, the invention provides a method for preparing potassium fluosilicate from fluorine-containing wastewater, which comprises the following steps:

(1) conveying the potassium chloride solid particles and water into a dissolving tank, and stirring for 10-12min to obtain a potassium chloride saturated solution;

(2) pumping the fluorine-containing wastewater into a stirring tank, adding silicon dioxide into the stirring tank, stirring at the rotating speed of 300-500r/min for 10-15min, and standing for 25-35min to obtain a solution containing fluorine silicic acid;

(3) carrying out suction filtration on the solution containing the fluosilicic acid by using a vacuum pump to obtain a silicon dioxide filter cake and filtrate;

(4) injecting the potassium chloride solution and the filtrate into a reactor, controlling the reaction temperature to be 45-55 ℃, stirring for 15-20min at the rotating speed of 1000-1500r/min, and standing for 1-2h to obtain liquid containing fluorine potassium silicate;

(5) and filtering and drying the liquid containing the fluorine potassium silicate to obtain the potassium fluosilicate.

Preferably, the stirring temperature in the step (1) is 25-30 ℃.

Preferably, the reaction temperature in the step (2) is 48-52 ℃, the rotation speed is 1200-1400r/min, the stirring time is 16-18min, and the standing time is 1.4-1.8 h.

Preferably, the reaction temperature in the step (2) is 50 ℃, the rotating speed is 1300r/min, the stirring time is 17min, and the standing time is 1.5 h.

Preferably, the silica filter cake in the step (3) may be put into the agitation tank again for reuse.

Preferably, lime is added into the filtrate obtained in the step (5) for neutralization, so that the harm to the environment is reduced.

The invention has the beneficial effects that:

according to the invention, silicon dioxide is added, the silicon dioxide reacts with hydrogen fluoride in the fluorine-containing wastewater to generate fluosilicic acid, and the fluosilicic acid reacts with a potassium chloride solution to generate potassium fluosilicate, so that the phenomenon that the fluorine-containing wastewater and soda lime are directly neutralized by using a traditional means to form calcium fluoride and other calcium salt precipitates containing a large amount of impurities is avoided, the hydrofluoric acid and the fluosilicic acid in the fluorine-containing wastewater are well utilized, the waste of resources is avoided, and meanwhile, the generated potassium fluosilicate is used for wood corrosion prevention, ceramic manufacturing, aluminum and magnesium smelting, agricultural pesticides, optical glass manufacturing, synthetic mica, porcelain glaze manufacturing and other aspects, and is beneficial to improving the economic benefit;

in addition, the silicon dioxide can adsorb other impurity ions in the solution, such as sulfate radicals, phosphate radicals and other ions, and the sludge amount generated by post-treatment can be relatively reduced;

the invention controls the temperature of the reactor at 45-55 ℃, which is beneficial to the full reaction of potassium chloride and fluosilicic acid, and in the 45-55 ℃ section, the reaction rate of potassium chloride and fluosilicic acid is higher, the time for generating potassium fluosilicate is shorter, the working efficiency is improved, if the temperature is too high, the potassium fluosilicate can be hydrolyzed to be hydrolyzed into potassium fluoride, hydrogen fluoride and silicic acid, which is not beneficial to the production of potassium fluosilicate.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.