Recycling Tungsten from Tungsten Catalyst

Tungsten catalyst has been widely used in various oxidation systems due to its excellent catalytic performance. In order to better control production cost and realize large-scale economic production with tungsten catalyst for oxidation reaction, at the same time, in order to save precious tungsten resources, avoid tungsten pollution in the environment and save environmental production, tungsten catalyst must be recycled and reused.

At present, some scholars have provided a method of recovering tungsten from the oxidation reaction solution containing tungsten catalysts, which can reduce the operating cost of the tungsten recovery process and increase the recovery rate of tungsten.

For example, the reaction system of H₂O₂ oxidizing cyclohexene to adipic acid is recovered from a catalyst containing tungsten, the reaction of Cyclohexene to adipic acid by hydrogen peroxide oxidation is completed after cooling, then the precipitated product crystal is filtered and separated from the system, then the reaction solution is added to the NaOH to adjust the reaction liquid pH to 7, the concentration of nitrate is added. Acid precipitates a lot of precipitates, filters after cooling, scours and precipitates with dilute nitric acid. In order to get the accurate recovery rate, the yellow solid is roasted and the X ray powder diffraction method is used to analyze all the tungsten trioxide. After weighing, the recovery rate of tungsten element is 83.3%.

The main characteristics of the method are as follows: adding alkaline substance to the organic oxidation reaction liquid containing tungsten catalyst to adjust the pH value, then adding acid substance to reverse the pH value and precipitate tungsten in the form of tungstic acid in the acidic environment, finally, the tungsten is separated from the reaction solution by separating the precipitated tungstate.

The recovery rate of tungsten in the oxidation reaction system of recovering tungsten catalyst is high. It can not only recycle all tungsten in the waste liquid from the oxidation reaction system of the tungsten catalyst, reduce the loss of valuable metals to zero, save valuable tungsten resources, solve the pollution of the tungsten flow to the environment. The process has reduced the use of acid, it has dual economic and environmental benefits.

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