Method for removing arsenic from yellow phosphorus through oxidation

Abstract

The invention discloses a method for removing arsenic from yellow phosphorus through oxidation. The method comprises the following steps: oxidizing arsenic in yellow phosphorus into a soluble arsenic compound to enter a water phase, so as to remove arsenic under interaction of a mixed arsenic remover solution and yellow phosphorus in a molten state at normal pressure, wherein the mixed arsenic remover solution comprises a basic oxidant, an oxidation catalyst and an enhanced oxidant; finally washing by ultrapure water for a plurality of times, so as to obtain the yellow phosphorus free of arsenic. The yellow phosphorus forms good emulsion particles under the action of the mixed arsenic remover, so that the contact area of the arsenic remover and the yellow phosphorus is greatly increased; the persistence and the high efficiency of the arsenic removal effect in the overall arsenic removal process are ensured by adopting a mode of feeding an oxidation reinforcer for a plurality of times by stages, the arsenic removal reaction is carried out more rapidly and efficiently by the oxidation catalyst, high yield of the yellow phosphorus is achieved while high-efficiency arsenic removal is ensured, the method is a high-efficiency, safe and economical arsenic removal method, and the method has good economic benefits and social benefits.

Description

technical field [0001] The invention relates to the field of yellow phosphorus processing in the phosphorus chemical industry, and relates to a method for removing arsenic by oxidation of yellow phosphorus. Background technique [0002] Yellow phosphorus is an important basic raw material for phosphorus chemical industry. Industrial yellow phosphorus contains a variety of trace impurities, which seriously affect its application and the development of fine phosphorus chemical industry. Among them, arsenic is a major impurity. The requirements for the content of yellow phosphorus are getting higher and higher; in addition, in industries such as high-purity phosphoric acid, semiconductors, petrochemicals, and automobile manufacturing, the requirements for the purity of yellow phosphorus are also getting higher and higher. [0003] At present, there are many kinds of processes for removing arsenic from yellow phosphorus reported at home and abroad, which can be summarized into ...

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Problems solved by technology

[0005] Japanese patent JPS5493692A uses nitric acid or sulfuric acid and their mixtures as oxidants, and the acid concentration in the aqueous phase is 20%-50%, but a large amount of phosphorus is oxidized and lost in this method, and a large amount of mixed acid waste liquid containing phosphoric acid, nitric acid or sulfuric acid is produced at the same time , in the production process will also produce a large amount of acid waste gas containing nitrogen oxides

[0006] Chinese patent CN102107859A uses active carbon adsorption combined with dilute nitric acid washing to purify yellow phosphorus. The concentration of dilute nitric acid is 8%-15%. This method will produce a large amount of acid waste gas containing nitrogen oxides and waste containing mixed acids of phosphoric acid and nitric acid during nitric acid washing. At the same time, when activated carbon is used for adsorption and filtration, due to the adsorption of activated carbon, part of the yellow phosphorus is adsorbed on the surface of activated carbon to form mud phosphorus containing elemental phosphorus, resulting in unnecessary loss of yellow phosphorus; the mixture after absorbing yellow phosphorus to activated carbon When washing with deionized water, a large amount of washing water will be generated

[0007] Chinese patent CN1962420A, using carbonate of 8%-15% of the weight of industrial yellow phosphorus added to the liquid industrial yellow phosphorus, stirring and washing, then static sedimentation, and then adding 150%-200% of the weight of yellow phosphorus containing nitric acid concentration of 15%-18% and 10%-40% by weight of yellow phosphorus in a mixed solution containing 6-10% iodine, and then add activated carbon powder to stir and filter to obtain the finished product. It can be seen from the description that there are many types of arsenic removal reagents used in this method, including: Acid, alkali and activated carbon, etc., so the method process is long and the operation is cumbersome; when nitric acid and iodine-containing compounds are used for treatment, a large amount of acid waste gas containing nitrogen oxides and mixed waste liquid containing nitric acid, iodine compounds, and phosphoric acid will be produced; When activated carbon is used for adsorption, a large amount of mud phosphorus containing elemental phosphorus is produced, resulting in unnecessary loss of yellow phosphorus, which makes the production cost higher, and a large amount of washing wastewater is generated in the washing process; at the same time, high-value iodine-containing compounds are used as arsenic removal reagents, further increased production costs

[0008] Chinese patent CN1257040 uses halogen-containing compounds to add dilute nitric acid 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, This method has a large loss of phosphorus, but the removal rate of arsenic is limited; this method will produce a large amount of acid waste gas containing nitrogen oxides during treatment, as well as waste liquid containing nitric acid, halides and a small amount of phosphoric acid

[0010] To sum up, according to the different oxidizing agents selected in the prior art, the aqueous phase oxidation arsenic removal method has the disadvantages of arsenic removal due to the high price of the arsenic removal agent used, the large loss of phosphorus, the long and cumbersome process of the arsenic removal process, etc. The effect is not obvious, the production cost is high, the safety performance is poor, the purity is low, etc.

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