Scheelite Flotation and Comprehensive Plaster Recycle

At present, the scheelite flotation method in our country is mainly used to treat scheelite with alkali pressure cooker treatment technology of wolframite. However, the process consumes large amount of energy, high production cost and large waste water discharge in subsequent processes. does not meet China's energy-saving emission reduction, low-carbon economy development requirements.

Recently, the research team proposed a phosphate / sulfate decomposition of Scheelite Flotation scheme. This method has no pollution, low cost, low energy consumption, simple operation and high yield, in addition, it can also recover high quality plaster.

The process of phosphoric acid / sulfuric acid decomposition of scheelite flotation is: the concentration of 5% ~ 35% P2O5 phosphoric acid solution, adding sulfuric acid and SO₄^2- concentrations in 0.10g/ml ~ 0.40g/ml, heating to 70 to 100 DEG C, The scheelite is added to the solution for reaction, the liquid to solid ratio is 3: 1 to 8: 1 ml / g, and the reaction time is 1 to 6 hours. After the reaction, the filtrate obtained by the filtration is subjected to basic ion exchange and basic solvent extraction Or ammonium salt precipitation method to extract tungsten.

In the first half of the two decomposition of scheelite, gypsum control the formation of stable and thick, not the pursuit of high tungsten decomposition rate and low loss rate of P₂O₅. In the second half of the scheelite decomposition, the smooth recrystallization of the resulting dihydrate gypsum is converted into a single, stable, semi-hydrated gypsum with good filtration and washing performance by adjusting the experimental conditions, and the undecomposed tungsten ore is further decomposed, the loss of intergranular P₂O₅ is also released, further increasing the gypsum quality.

A small amount of not completely decompose scheelite can be further decomposed, the decomposition rate was above 98%; intergranular P₂O₅ loss has been released, the loss of P₂O₅ in the slag is reduced to below 0.5%, and phosphoric acid and sulfuric acid can be recycled again, reducing the cost of leaching; The scheelite beneficiation process does not need to set up a special dephosphorization process, saving the cost and loss of tungsten phosphorus reagent; And achieve zero discharge of wastewater, the quality of by-product obtained hemihydrate gypsum is very pure, even comparable with natural gypsum, gypsum board production, production of cement retarder, plaster provides high quality raw material, the production process has no waste emissions, improve economic efficiency and environmental benefits.

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