Method for preparing sodium fluoride and co-producing calcium ammonium nitrate fertilizer by using ammonium fluoride

Abstract

The invention relates to the technical field of inorganic chemical industry, in particular to a method for preparing sodium fluoride and co-producing a calcium ammonium nitrate fertilizer by using ammonium fluoride. The method comprises the following steps: firstly, preparing sodium fluoride: preparing the ammonium fluoride into a saturated solution, adding sodium nitrate therein to produce sodiumfluoride and an ammonium nitrate solution, filtering to obtain a sodium fluoride solid, washing, and drying to obtain an industrial sodium fluoride product; then defluorinating an ammonium nitrate filtrate: adding a small amount of lime milk into the ammonium nitrate solution, defluorinating the solution, precipitating fluoride ions in a liquid phase, then filtering the ammonium nitrate solution,precipitating, washing and drying to obtain artificial fluorite; then, preparing the fully water-soluble calcium ammonium nitrate fertilizer: adding the lime milk of lime, reacting at high temperature, enabling a reaction phase to form sub-molten salt, enabling ammonia to escape, washing by using phosphoric acid to obtain a raw material for preparing an ammonium phosphate product, cooling the sub-molten salt slurry, granulating, and drying to obtain a fully water-soluble calcium ammonium nitrate fertilizer product.

Description

technical field [0001] The invention relates to the technical field of inorganic chemical industry, in particular to a method for preparing sodium fluoride and co-producing calcium ammonium nitrate fertilizer by using ammonium fluoride. Background technique [0002] Sodium fluoride (NaF) is an important chemical raw material, and it is the main source of fluoride ions in many fluorine compounds. Main uses: as raw materials for the manufacture of other fluorides; agricultural pesticides, sterilization; also used as wood preservatives, water treatment agents, light metal fluoride salt treatment agents; cleaning fluids for steel and other metals, fluxes and fluxes; ceramics, glass And enamel flux and opacifying agent, raw hide and skin treatment agent in tanning industry; preservative of glue, etc. [0003] At present, the methods for producing industrial sodium fluoride include immersion method, hydrofluoric acid neutralization method, ammonium fluoride soda ash method, and s...

AI Technical Summary

Problems solved by technology

This process has low requirements on raw materials, and the price of raw materials is cheap; but the production cost of the product is not low, which is mainly due to the following disadvantages of this process: first, the material reaction is not complete, and the yield is not high; second, the solubility of sodium fluoride in water It is very small and does not change much with the temperature, resulting in a very low leaching rate; third, the high calcination temperature makes the agglomerate hard, not easy to crush, and also makes leaching difficult; fourth, the energy consumption is too high, resulting in high production costs ; Fifth, the production process has relatively high environmental pollution

The products produced by this process have good appearance and good quality. Most of the raw materials are sodium fluorosilicate, a by-product of phosphate fertilizer plant, but the current price of sodium fluorosilicate has reached 1600-1900 yuan / ton, and the quality of Poor, it can only be treated as solid waste, and the separation of sodium fluoride and silica gel will produce a large amount of waste water, and a large amount of CO2 gas will be discharged into the atmosphere, so this process has a greater impact on the environment

[0008] At present, the industry mostly adopts the sodium fluorosilicate soda ash method for production. Although the product quality is good, a large amount of sewage will be generated during the reaction process, and the produced CO 2 The gas needs to be completely discharged, so it has a greater impact on the environment and the greenhouse effect

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