Method for deeply removing phosphorus in coarse sodium tungstate solution

Abstract

The invention relates to a method for deeply removing phosphorus in a coarse sodium tungstate solution. The method is characterized in that in ammonium paratungstate production adopting an ion exchange method, a sample is taken from a coarse sodium tungstate solution obtained by reduced pressure decoction leaching, a detection result shows that a phosphorus-tungsten mass ratio of the sample is greater than or equal to 0.0007%, the material liquid is heated to a temperature of 90+ / -5 DEG C, light calcium carbonate is used as a phosphorus removal agent so that a reaction rate is fast and phosphorus removal efficiency is high, the phosphorus removal agent is added into the material liquid, wherein the use amount of the phosphorus removal agent is 2-15 times mass of phosphorus in the material liquid, the mixed solution undergoes a reaction for 30min under the conditions of thermal insulation and stirring so that phosphate groups in the phosphorus removal agent and the material liquid form difficultly soluble calcium hydrogen phosphate precipitates under the alkaline conditions, the reaction product liquid is filtered by a plate-and-frame filter press so that solid-liquid separation is realized and a novel solution with phosphorus content less than 0.06g / l and precipitates are obtained, and the novel solution subjected to phosphorus removal is used for production of ammonium paratungstate. Through the method, a phosphate mass concentration of the sodium tungstate solution is less than 0.5mg / l and a phosphorus removal rate is more than 99%.

Description

technical field [0001] The invention relates to a method for deep phosphorus removal of crude sodium tungstate solution, which provides a deep phosphorus removal process for crude sodium tungstate solution. Background technique [0002] In the process of producing ammonium paratungstate by ion exchange method, the crude sodium tungstate solution obtained from the decomposition of tungsten concentrate by alkali method contains high phosphorus salts. If the phosphorus salts in the solution are not specially removed, and enter the next process of resin adsorption, it is easy to cause The phosphorous content of ammonium paratungstate in the product exceeds the standard of 7ppm, so that the purity of the product ammonium paratungstate does not meet the requirements and becomes a waste product. A common method for phosphorus removal is to add magnesium chloride solution to crude sodium tungstate solution to form magnesium phosphate precipitation, and remove phosphorus by filtering...

AI Technical Summary

Problems solved by technology

However, this method forms a large amount of precipitated slag, which causes a lot of tungsten loss and is difficult to recycle; in addition, chloride ions are brought into the sodium tungstate solution, which greatly reduces the ability of the resin to adsorb tungsten, resulting in the loss of tungsten in the next process and affecting tungsten metal. Recycling and Productivity

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