Method for oxidizing yellow phosphorus to remove arsenic

Abstract

The invention provides a method for oxidizing yellow phosphorus to remove arsenic, and belongs to the technical field of chemical engineering. The method for oxidizing yellow phosphorus to remove arsenic comprises the following steps of: premixing an oxidant solution and an oxidation catalyst solution by using a mixer, introducing the obtained mixed fluid into a micro-dispersion element to be mixed with a yellow phosphorus raw material, carrying out an oxidation-reduction reaction in a micro-packed bed, and carrying out phase splitting to obtain arsenic-removed yellow phosphorus, wherein the oxidation catalyst solution comprises a potassium iodide solution or a hydrogen iodide solution. Through efficient mixing of the oxidant solution and the oxidation catalyst solution, effective formation of I2 can be ensured, and meanwhile, I2 is prevented from being separated out of the solution; the yellow phosphorus raw material and the mixed fluid keep a huge liquid-liquid phase interface in themicro-dispersion element and the micro-packed bed, shuttling of I2 between a yellow phosphorus phase and a water phase is effectively enhanced, the arsenic removal reaction speed is increased, the high arsenic removal rate and the high phosphorus yield can be achieved at the same time, operation is easy, consumed time is short, and the method is suitable for large-scale production.

Description

technical field [0001] The invention relates to the technical field of chemical industry, in particular to a method for oxidatively removing arsenic from yellow phosphorus. Background technique [0002] Yellow phosphorus is an important basic raw material for the production of fine phosphorus chemical products. Industrial yellow phosphorus contains various impurities such as organic matter, arsenic, sulfur, iron, etc., and its content directly affects the application range of yellow phosphorus. Among them, arsenic and phosphorus belong to the same main group, and their properties are very close. It is easy to enter the product in the production of yellow phosphorus. The content of arsenic in industrial yellow phosphorus can be as high as 300-400ppm. It is difficult to remove and has a great impact on the quality of yellow phosphorus. Moreover, arsenic is a highly toxic element, and its detection amount is subject to very strict restrictions in applications such as food, med...

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Problems solved by technology

For example, Chinese patent 200710065980.3 discloses one or more of hydrogen peroxide, nitric acid and hypochlorous acid as the base oxidant, bromine, bromic acid, bromate, bromide or their mixture as oxidation enhancer, and yellow phosphorus Put them together into a stirring reactor and react at 50-90°C for 1.5-3 hours to remove arsenic. Although the phosphorus yield can reach 99% when the arsenic removal rate is 76.7%, the phosphorus yield is less than 93% when the arsenic removal rate is 98.6%. , can not achieve high arsenic removal rate and high phosphorus yield at the same time, and the reaction time is long

Chinese patent 201310743962.1 discloses that nitric acid solution is used as the basic oxidant, potassium iodide solution is used as the oxidation catalyst, and sodium hypochlorite solution is used as the oxidation enhancer, and the basic oxidant, yellow phosphorus, oxidation catalyst, and oxidation enhancer are sequentially put into the stirred reactor at a certain time interval. agent, the feeding time is more than 2 hours, and the reaction time is 3 hours. After the reaction, the arsenic yellow phosphorus is obtained by washing with water, but the feeding and reaction time are long, and the production efficiency and safety are not ideal.

Chinese patent 201310747146.8 discloses that peroxyphosphoric acid with a concentration of 10-50% is used as an oxidizing agent, which is added together with yellow phosphorus into the reactor for stirring and mixing, and reacted at 50-85°C for 2-4 hours. The oxidizing agent in this process is easy to recycle. However, the arsenic removal efficiency is below 80%, the arsenic removal effect is not ideal, and the reaction time is long

It can be seen that the water-phase oxidative arsenic removal technology generally has the common problems of long reaction time, difficulty in balancing arsenic removal rate and phosphorus yield

[0004] Chinese patent 201810668537.3 discloses the use of a microchannel reactor to improve the contact between the two phases. Nitric acid, hydrogen peroxide or hypochlorous acid with a concentration of 5-20% is used as an oxidant, and the desorption can be completed after 5-60 seconds of contact at 50-90°C. Arsenic reaction, but it is still difficult to balance the arsenic removal rate and phosphorus yield

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