The main raw material of black corundum is a kind of black corundum with a content of 70% to 80% aluminum oxide (AI2O3) and more impurities such as silicon oxide and titanium oxide. It is a new type of environmentally friendly material.
Black corundum, also known as low-alumina corundum, is a kind of gray-black crystal with α-Al2O3 and iron spinel as the main mineral phase, which is produced by smelting bauxite in an electric arc furnace. It is characterized by a low Al2O3 content , and a certain amount of Fe2O3 exists, so it has the characteristics of moderate hardness, high toughness, high temperature resistance and stable thermal performance. It is mostly used for free grinding, such as grinding and rough grinding of products before electroplating. It is mainly used for polishing and sandblasting of stainless steel, metal products, optical glass, bamboo and wood products. It is also a novel abrasive for manufacturing resin grinding wheels, cutting discs and emery cloths.
Black corundum is widely used in the surface treatment industry, which can make various surface treatment processes smoother, and can be divided into the following categories:
1. Surface processing: metal oxide layer, carbide black skin, metal or non-metal surface rust removal, such as gravity die-casting mold, rubber mold oxide or release agent removal, ceramic surface black spots, uranium color removal, painting rebirth.
2. Beautification processing: all kinds of gold, K gold jewelry, matte or matte treatment of precious metal products, non-metallic matte processing of crystal, glass, corrugated, acrylic, etc., and can make the surface of processed objects have a metallic luster.
3. Etching processing: jade, crystal, agate, semi-precious stones, seals, elegant stones, antiques, marble tombstones, ceramics, wood, bamboo etc.
4. Pretreatment processing: Teflon, PU, rubber, plastic coating, rubber roller, electroplating, metal spray welding, titanium plating and other pretreatments to increase surface adhesion.
5. Burr processing: remove the burrs of bakelite, plastic, zinc, aluminum die-casting products, electronic parts, magnetic cores, etc.
6. Stress relief processing: stress relief processing for aerospace, national defense, precision industrial parts, rust removal, paint removal, matting, and renovation.
7. Electronic parts processing: fogging and etching of silicon chips, removal of impurities on the back of wafers, overflow of electronic parts packaging, removal of printed characters on the surface of finished products, and cleaning of ceramic electric heating.
8. Mold processing: sandblasting of general mold surface, matte surface treatment after mold bite, wire cutting mold, glass mold, tire mold, conductive rubber mold, shoe mold, bakelite mold, electroplating mold, button mold, plastic products mold.
9. Processing of large workpieces: large workpieces such as oil tanks, chemical tanks, ship hulls, copper structures, metal houses, containers, automobile industries, etc., rust removal, paint removal, maintenance and automatic matte treatment of large flat glass.
The smelting method of black corundum is basically the same as that of brown corundum. The production method of black corundum is to select raw materials such as high-quality bauxite, iron oxide, etc., add other trace elements, and carefully smelt through a dumping electric arc furnace to ensure that the smelted massive black corundum is all first-grade, with less impurities and high grade. ,stable quality. It has laid a foundation for the production of segment sand, grain size sand and fine powder with moderate hardness, good toughness and excellent and stable performance.