I. Graphite Ore Beneficiation Process Flow
(a) Flotation Method for Purifying Graphite Ore
The flotation method is commonly used for purifying flake graphite ore. This process involves multiple re-grinding and re-separation stages to protect the graphite flakes and improve the yield and grade of large flakes. In the flotation process, materials such as kerosene, diesel, and other collectors are used, with 2-oil and 4-oil as frothers. This method has a low cost but a complex process and is difficult to control in production.
(b) Alkali-Acid Method for Purifying Graphite Ore
The alkali-acid method consists of an alkali fusion and an acid leaching process. In the alkali fusion process, graphite is mixed with sodium hydroxide and then calcined at high temperatures, causing impurities to react with alkali to form water-soluble or acid-soluble salts, which are then removed by washing. The acid leaching process treats the product from the alkali fusion to further purify the graphite. This process has simple equipment but high energy consumption and is corrosive to the equipment.
(c) Hydrofluoric Acid Method for Purifying Flake Graphite Ore
The hydrofluoric acid method involves reacting graphite with hydrofluoric acid to generate water-soluble compounds, which are then washed to remove impurities. This process has a simple flow and low cost, but hydrofluoric acid is highly toxic and requires strict safety precautions.
(d) Chlorination Roasting Method for Purifying Graphite Ore
The chlorination roasting method involves mixing graphite with a reducing agent and then roasting at high temperatures. Impurities in the graphite, such as silicates and aluminosilicates, decompose into oxides at high temperatures, which react with chlorine gas to form gaseous or condensed chlorides that are then vaporized and removed, achieving purification. This method is suitable for graphite ores containing silicates but is less commonly used due to the toxicity of chlorine gas and the risk of equipment corrosion.
(e) High-Temperature Method for Purifying Graphite Ore
The high-temperature method utilizes the high melting point of graphite for purification, achieving a purity of up to 99.99%. However, this method has high energy consumption and strict requirements for equipment and raw materials.
II. Graphite Ore Beneficiation Equipment Selection
(a) Crushing Equipment
Jaw Crusher: Suitable for the primary crushing of graphite ore, characterized by a large crushing ratio and simple structure.
Cone Crusher: Used for the secondary crushing of graphite ore, offering high crushing efficiency and uniform product size.
(b) Grinding Equipment
Select appropriate mills based on the type of graphite (crystalline or amorphous), such as ball mills.
(c) Separation Equipment
Flotation machines are commonly used for the separation of graphite ore, such as SF, BF, JJF, and other types.
(d) Concentration and Dewatering Equipment
Efficient concentrators and belt filters are used for the dewatering of flotation-separated graphite concentrate.
(e) Other Equipment
This includes efficient mixing tanks, drying equipment, washing equipment, chemical treatment equipment, and electromagnetic separation equipment.
III. Summary
The beneficiation process for graphite ore is diverse, including flotation, alkali-acid, hydrofluoric acid, chlorination roasting, and high-temperature methods. Equipment selection should be based on the properties of the graphite ore, the requirements of the beneficiation process, and the production scale to achieve efficient, economical, and environmentally friendly graphite ore beneficiation production.