Method for recycling tungsten and ammonia in one step from ammonium paratungstate crystallization mother solution smelt through tungsten

Abstract

The invention discloses a method for recycling tungsten and ammonia in one step from an ammonium paratungstate crystallization mother solution smelt through tungsten. After the ammonium paratungstate (APT) is subjected to evaporative crystallization, a mother solution is pumped into a reaction kettle for stripping treatment, calcium oxide with content above 90% or calcium hydroxide with content above 95% are added into the mother solution, a stripping process which is commonly used in the crystallization mother solution in the APT preparation process is utilized to recycle the ammonia, the reaction temperature is in a range from 25 DEG C to 90 DEG C, when the ammonia is subjected to gas-liquid separation through condensation concentration, the ammonia is sprayed with a hydrochloric acid to prepare ammonium chloride to return to a main process to prepare an analytical solution, white tungsten slag returns to a pressure boiling process, when a potential of hydrogen (pH) value of a reaction system is maintained in a range from 9 to 11 and concentration of ammonia nitrogen in water is reduced to about 30mg / L, the reaction is finished, and a waste liquid free of the ammonia nitrogen is subjected to a mixing treatment with an ion exchange post-liquid which is generated in the main process working procedure. The method has the advantages that the process procedures are greatly simplified, the tungsten deposition rate is high, the process is simple, the operation is easy, and the treating cost is slightly low.

Description

technical field [0001] The invention belongs to tungsten hydrometallurgy, in particular to a method for recovering tungsten and ammonia in one step from ammonium paratungstate crystallization mother liquor produced by tungsten smelting. Background technique [0002] my country is a country with large tungsten resources. Tungsten resources mainly exist in the form of wolframite and scheelite. With the decreasing amount of wolframite resources, mining scheelite resources has become the main mineral variety of tungsten resources. The smelting technology of scheelite It has also been greatly improved, and the technology has been further matured. The ion exchange process has become the main process of tungsten smelting in my country. With the advancement of technology and the improvement of environmental protection awareness, most tungsten smelting enterprises have paid attention to the treatment of effluent wastewater and the improvement of the total recovery rate of tungsten, es...

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Problems solved by technology

[0004] ① Precipitation method, calcium chloride artificial scheelite precipitation - acid decomposition of scheelite - crude tungstic acid - return to the main process; this process usually uses calcium chloride as a precipitant, and supplemented with sodium hydroxide to adjust the pH value, in practical applications It is generally reflected that the tungsten precipitation is not complete, and the tungsten content in the liquid is still in the range of 100-200mg / L. This is because a large amount of ammonia is released when adding alkali to adjust the pH value. The working environment is harsh and not environmentally friendly. At the same time, most companies consider Considering the cost and environmental conditions, if the precipitant and alkali are not added in large quantities, the excess coefficient of calcium ions will inevitably be small and the precipitation of tungsten will not be complete.

[0005] ②Ion exchange method, this process usually uses acid to lower the pH value first, and then adsorbs tungsten through a large-pore resin. The desorption solution uses a strong alkali solution, and sodium tungstate is returned to the main process. High, the use has been vigorously promoted, but the process is relatively long

In the application of the stripping method, in order to dissociate the ammonium root of ammonium chloride into ammonia molecules, sodium hydroxide is usually added, and the cost is relatively high

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