Potassium fluoride,anhydrous
           Potassium fluoride,extra pure
           Potassium fluoride,Granular
           Silicon Dioxide
           Hydrofluoric acid
           Synthetic Cryolite
           Potassium Fluoaluminate
           Ammonium bifluoride
           Potassium Bifluoride
           Aluminium fluoride
           Sodium fluoride
           Potassium Fluorosilicate
           Fluorosilicic Acid
           Sodium silicofluoride
           Potassium Hydroxide Flakes
           Magnesium Fluoride
           Magnesium fluorosilicate
           Barium Fluoride
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Any silicate can be dissolved in hydrofluoric acid, which makes hydrofluoric acid a special reagent for the treatment of insoluble minerals in graphite. Since 1979, domestic and foreign have developed a gaseous hydrogen fluoride, liquid hydrofluoric acid system and ammonium fluoride salt system of purification methods, of which the most widely used liquid hydrofluoric acid, which uses graphite impurities and hydrofluoric acid reaction Soluble in water fluoride and volatiles to achieve the purpose of purification.

However, hydrofluoric acid and CaO, MgO, Fe2O3, etc. reaction will be precipitated.

In order to solve the above precipitation problem, the addition of a small amount of hydrofluoric acid, dilute hydrochloric acid, nitric acid or sulfuric acid, etc., can remove Ca, Mg, Fe and other impurities interference.

Hydrofluoric acid purification of graphite and a certain percentage of hydrofluoric acid in the preheated together with the reactor with a stirrer, to be fully wet after the timing of stirring, the reactor temperature controlled by the thermostat to reach the specified time. Timely removal of excess acid, the filtrate recycling, filter cake washed by hot water to neutral after dehydration drying obtain product. 

Hydrofluoric acid method is a relatively good purification program, the 20th century, 90 years has been the industrialization of production, Europe and the United States and other countries than in China is more common. As the method of equipment corrosion, and toxic, ten years ago, some people with dilute acid and fluoride two-step treatment to remove impurities in graphite. Japan, France and other countries have introduced a patent with ammonium fluoride or ammonium fluoride and 93% of the carbon content of graphite powder reaction, the fixed carbon content of graphite can be increased to 99.95%. In view of the great toxicity of hydrofluoric acid, the production process must have strict safety protection and waste water treatment system.