Yellow phosphorus arsenic removing method

Abstract

The invention relates to a purification method of phosphor, especially to a method for arsenic removal by oxidization. The invention comprises following steps: fully stirring and mixing phosphor and aqueous oxidant at a temperature of 50-90 DEG C, removing the arsenic from phosphor by enabling the arsenic from phosphor into the aqueous phase, wherein the aqueous oxidant consists of basic oxidant and oxidation reinforcer, the basic oxidant comprises hydrogen peroxide, nitric acid, hypochlorous acid or the mixture thereon, the oxidation reinforcer comprises bromine, bromic acid, bromate, bromide or the mixture thereon. The purification method according to the invention has advantages of high arsenic removal rate, high efficiency and characters of simple, economic and safe.

Description

technical field [0001] The invention belongs to the field of inorganic chemical industry and relates to a method for purifying yellow phosphorus, in particular to a method for removing arsenic by oxidation. Background technique [0002] Yellow phosphorus is an important chemical raw material. In some specific application fields, such as: pharmaceutical intermediates and electronic materials such as indium phosphide and gallium phosphide, yellow phosphorus requires high purification. Because yellow phosphorus has spontaneous combustion, it is generally stored in Under the water surface, industrial-grade yellow phosphorus contains a variety of trace impurities, such as: iron, arsenic, antimony, silicon, sulfur, organic matter (commonly known as oil), etc., depending on factors such as production raw materials and working conditions, and arsenic mainly exists as arsenate In phosphate rock, since phosphorus and arsenic belong to two adjacent elements of the same main group, they...

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Problems solved by technology

[0005] Japanese patent S52-160060: Nitric acid or sulfuric acid and their mixtures are used as oxidants, and the acid concentration in the aqueous phase is 20% to 50%, but this method has a large amount of phosphorus oxidized and lost, and produces a large amount of mixed acid waste liquid

[0006] Japanese Patent HEI5-43210: Using iodine or iodide and arsenic to form arsenic iodide (ASI 3 ) above the boiling point of phosphorus to obtain phosphorus with lower arsenic content. This method reduces the yield of low arsenic and phosphorus due to the existence of a large amount of raffinate containing arsenic iodide. In addition, the amount of iodine and iodide required to be added is equivalent to that of raw material yellow The theoretical chemical equivalent of arsenic in phosphorus is about 10,000 times, so the consumption of expensive iodine and iodide is relatively large

[0007] World Patent WO99 / 62819: Using mixed oxidants to remove arsenic in liquid phase, one of the mixed oxidants is iodine, iodic acid or iodate, and the other contains hydrogen peroxide, persulfate, perpyrosulfate, hypochlorous acid and its salts Etc., this method exists when iodine and iodine-containing substance addition is low, and arsenic removal rate is low, and when addition is high, iodine is volatile, and causes loss, if adopt a sealed pressure reactor to reduce the loss of iodine, again It will increase the cost of the device and the risk of the process. At the same time, because iodine and iodide are relatively expensive, the production cost of this method is relatively high.

[0008] Chinese patent CN1315289: A chemical oxidation method using an oxidant, an oxidation enhancer, and a phase transfer catalyst as a liquid phase. Although the arsenic removal effect is good and the safety is high, the oxidation enhancer and the phase transfer catalyst will remain in the yellow phosphorus, making the yellow phosphorus Introduction of new impurities in finished phosphorus products

[0009] Chinese patent CN1257040: Add dilute nitric acid to the compound containing halogen elements to treat yellow phosphorus as a liquid-phase oxidant. This method has a large amount of halide added, and the weight ratio of the treatment liquid to yellow phosphorus is also large (about 4-5 times), relatively speaking. , the loss of phosphorus is large, but the removal rate of arsenic is very limited

[0010] In a word, the above-mentioned method for removing arsenic by aqueous phase oxidation has defects such as low arsenic removal rate, high cost, poor safety, or low purity during the treatment process due to improper selection of oxidant.

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