Treatment method of sodium tetrachloroaluminate generated in production process of methyl dichlorophosphine

Abstract

The invention provides a treatment method of sodium tetrachloroaluminate generated in a production process of methyl dichlorophosphine, wherein the treatment method comprises the steps: adding sodium tetrachloroaluminate solid slag into a sodium hydroxide solution, stirring for reaction to obtain mixed slurry, filtering to obtain aluminum hydroxide solid and first filtrate, washing and drying the aluminum hydroxide solid, and collecting second filtrate generated in the washing process; roasting the aluminum hydroxide solid to obtain aluminum oxide; concentrating the first filtrate and the second filtrate to obtain a concentrated solution, carrying out solid-liquid separation to obtain a first crude sodium chloride product and a concentrated mother solution, removing moisture in the concentrated mother solution, and drying to obtain a second crude sodium chloride product; combining the first crude sodium chloride and the second crude sodium chloride and heating to remove impurities, and thus obtaining refined sodium chloride; and adding pure water into the refined sodium chloride to prepare a saturated saline solution, adding calcium chloride, filtering to obtain third filtrate, adding sodium carbonate and sodium hydroxide into the third filtrate, filtering to obtain a primary refined saline solution, and performing resin treatment to obtain a secondary refined saline solution.

Description

technical field [0001] The invention relates to the field of industrial by-product treatment, in particular to a treatment method for sodium tetrachloroaluminate produced in the production process of methyl dichlorophosphine. Background technique [0002] Methyl dichlorophosphine is an important organic chemical intermediate, which is widely used in the fields of pesticides, medicines, flame retardants, etc., especially for the synthesis of key intermediates of glufosinate-ammonium Mono-n-butyl phosphonite. At present, the synthesis of methyl dichlorophosphine mainly adopts the following two methods: 1. Taking phosphine trichloride, methyl chloride and aluminum chloride as raw materials, adding a solvent, and generating complex MePCl under a pressure of 3kgf 4 ·AlCl 3 , isolate air and moisture, filter to remove solvent and excess phosphine trichloride, obtain MePCl 4 ·AlCl 3 solid, then put the solid into a stirred reactor, add dropwise yellow phosphorus or drop in alum...

AI Technical Summary

Problems solved by technology

This treatment method is to use relatively expensive sodium hydroxide to prepare polyaluminum chloride with low added value. During the reaction, an oxidant needs to be added to oxidize the organic phosphorus compound into an inorganic phosphorus compound. After sodium tetrachloroaluminate is dissolved in water, the whole The system is strongly acidic. After adding an oxidant, the chloride ions in the strong acidic system will be oxidized preferentially, and highly toxic chlorine gas will be produced. There is a great safety hazard in large-scale application. To completely oxidize organic phosphorus into inorganic phosphorus requires Adding a large amount of oxidizing agent is costly and not environmentally friendly

In addition, this treatment method washes the obtained sodium chloride solid with water, causing a part of sodium chloride to remain in the mother liquor to become high-salt wastewater, and the incompletely oxidized organic phosphorus and the oxidized inorganic phosphorus will simultaneously exist in the high-salt wastewater , after entering the biochemical system, it will cause the death of the bacteria, and without other treatment, organic phosphorus wastewater will be generated, which cannot be discharged directly

[0009] In summary, the treatment methods disclosed in the prior art have problems such as complicated process, high cost, inability to completely remove organic phosphine-containing substances, and low added value of the products obtained from the treatment. Therefore, it is urgent to develop an efficient and thorough way to remove organic phosphine and High value-added reuse method of sodium tetrachloroaluminate

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