Method for removing fluorine from sulfate solution

A sulfate and solution technology, applied in sulfate preparation, alkali metal sulfite/sulfate purification, alkali metal fluoride, etc., to achieve the effect of simple process, avoidance of fluorine-containing solid waste, and easy operation

Inactive Publication Date: 2018-08-07
CENT SOUTH UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

It was found that adding CaCO 3 It can only barely meet the requirement of F<50mg/L in the indus

Method used

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  • Method for removing fluorine from sulfate solution
  • Method for removing fluorine from sulfate solution

Examples

Experimental program
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Effect test

Embodiment 1

[0034] Take 5 m of zinc electrolyte solution with a pH of 5.2 3 , add calcium sulfate according to 4.5 times of the theoretical amount of fluorine converted into calcium fluoride, stir at room temperature for 2.5 hours to absorb and remove the fluorine, and filter to obtain the defluoridated liquid and fluorine-containing filter residue. The F content in the liquid after defluoridation is 13mg / L, which can be directly used for zinc electrolysis. The fluorine-containing filter residue is stirred into water at a solid-to-liquid ratio of 1:2g / mL, heated to 65°C, and potassium carbonate is slowly added to adjust the pH to 8.6. Continue to stir for 2.5h to make it completely transformed, and filter to obtain calcium carbonate filter cake and potassium fluoride solution. Then add sodium carbonate to the potassium fluoride solution according to 0.95 times of the theoretical amount converted into sodium fluoride, stir at 80°C for 1 hour, and filter to obtain sodium fluoride crystals a...

Embodiment 2

[0037]Take 1.5m of fluorine-containing sodium sulfate solution with a pH of 8.2 3 , add calcium sulfate according to 3.5 times the theoretical amount of fluorine converted into calcium fluoride, stir and ball mill at room temperature for 1 hour to absorb and remove the fluorine, and filter to obtain the defluoridated liquid and filter residue containing calcium fluoride. The content of F in the liquid after defluoridation is 12mg / L, which can be directly cooled to crystallized Glauber's salt, and the calcium fluoride-containing filter residue is added to water at a solid-to-liquid ratio of 1:3g / mL, and added at a rate of 1.3 times the theoretical amount of calcium converted into calcium carbonate. Ammonium carbonate was ball milled at room temperature for 1.5 hours to make it completely transformed, and filtered to obtain a calcium carbonate filter cake and a solution containing ammonium fluoride. Then add sodium carbonate to the solution containing ammonium fluoride according...

Embodiment 3

[0041] Take the smelting fume leach solution with a pH of 4.2, stir and add calcium sulfate according to 2.5 times the theoretical amount of fluorine converted into calcium fluoride, filter to form a 3.5cm thick filter cake, and then circulate the filtrate to contact with the filter cake to maintain both The time of the first contact is 0.002h, and the room temperature is contacted for 2.5h to obtain the defluoridated liquid and the filter residue containing calcium fluoride. The F content in the liquid after defluoridation is 19mg / L, which can be directly used to separate and recover the valuable metals in it. The calcium fluoride-containing filter residue is added to water at a solid-to-liquid ratio of 1:2g / mL, and converted into calcium carbonate according to the calcium in it. Potassium carbonate was added to 1.3 times the theoretical amount, ball milled at room temperature for 1 hour to make it completely transformed, and filtered to obtain a calcium carbonate filter cake ...

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Abstract

The invention provides a method for removing fluorine from a sulfate solution. The method comprises the following steps: enabling a fluorine-containing sulfate solution to be in contact with calciumsulfate; controlling the pH (Potential of Hydrogen) of the solution to be 1.5 to 9.5 and transforming the fluorine into calcium fluoride; carrying out liquid-solid separation to obtain a fluorine-removed solution and fluorine-containing filtering dreg; transforming the fluorine-containing filtering dreg to recycle a sodium fluoride crystal; utilizing the fluorine-removed solution for direct industrial production, so as to extract valuable metal. By utilizing the difference of solubility of CaF2 and CaSO4 in a water solution, calcium sulfate is in contact with the fluorine-containing sulfate solution; the fluorine is transformed into calcium fluoride and is removed through the liquid-solid separation; in a treated sulfate solution, the content of F is less than or equal to 20mg/L; then a transformation agent is added to separate and recycle fluorine in fluorine-removing dreg by utilizing the difference of the solubility of the CaF2 and the CaSO3 in the water solution, so that recycling of the CaSO4 in a technological process is realized. The removal of the fluorine in the sulfate solution is realized and requirements, on the fluorine in material liquid, by industrial production are met; the production of fluorine-containing solid wastes is avoided. The method provided by the invention has the advantages of simple technology, convenience for operation, cleanness and environment protection, economical and high efficiency and the like and is suitable for industrial application of the removal of the fluorine in the sulfate solution.

Description

technical field [0001] The invention belongs to the field of metallurgy and chemical industry, in particular to a method for removing fluorine from sulfate solution. Background technique [0002] Fluorine is a non-metal chemical element with active chemical properties and can react with most metals and non-metals to form compounds. Fluorine is widely distributed in minerals. Therefore, sulfate solutions obtained by decomposing minerals with sulfuric acid usually contain fluorine. The presence of fluorine not only affects the extraction of metals, but also is harmful to equipment and the environment. Therefore, people have done a lot of research on the removal of fluorine in sulfate solution. At present, the methods for removing fluoride in sulfate solution mainly include adsorption method, flocculation precipitation method and lime precipitation method. [0003] The adsorption method is to add silica gel (sodium silicate) or anion exchanger to the sulfate solution to remov...

Claims

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Application Information

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IPC IPC(8): C01B17/96C01D3/02C25C1/16C01D5/16
CPCC01B17/96C01D3/02C01D5/16C01P2006/80C25C1/16Y02P10/20
Inventor 王学文杜艳苹葛奇王明玉王懿
Owner CENT SOUTH UNIV
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