Graphite Purification Method

Graphite Purification Method

Graphite purification: chemical purification and physical purification of two methods.

(1) chemical purification is the use of graphite acid, alkali, corrosion resistance, with acid, alkali treatment of graphite concentrate, so that impurities dissolve, and then washed away, improve concentrate grade. High carbon graphite with grade 99% was obtained by chemical purification. Fundamental is under the condition of high temperature above 500 ℃, make the impurity in the graphite (mainly silicate minerals) and caustic soda, which react NaOH, produce water soluble reactants, water leaching reagents, can eliminate some impurities, another part of impurities, such as iron oxide, with HCl neutralization after alkaline fusion, generate sub water soluble ferric chloride, washing with water can be removed.

In the above process, the concentration of NaOH is about 50%, and the proportion of graphite is 1:0.8, that is, the production of 1T high carbon graphite consumes about NaOH 0.4T. The addition of HCl is about 30% of graphite. The fuel use of coal is approximately o.6 - o.7t. The equipment used in alkali fusion method is mainly anchor mixer, melting furnace, spiral slurry mixer, V-type washing tank, etc. The recovery rate is 85-90%, and the investment is 150,000-200,000 yuan. This process is more advanced, but there are also large water consumption, graphite loss, low productivity, large consumption of alkali, and discharge of waste liquid pollution and other shortcomings.

(2) physical purification is high temperature purification, the use of high temperature properties of graphite, put it in the electric furnace, isolated air heating to 2500 degrees C, so that ash (impurities) volatilized, so as to improve concentrate grade. High purity graphite with grade of 99.9% can be obtained by high temperature purification.