Abrasive paper, sand belt, sand cloth roll can be divided into two categories: natural abrasive paper, sand belt, sand cloth roll and artificial abrasive paper, sand belt, sand cloth roll.
All materials in nature that can be used for grinding or polishing are collectively referred to as natural abrasive paper, sand belt, and sand cloth roll. There are several commonly used natural abrasive papers, sand belts, and sand cloth rolls:
Diamond is currently known as the hardest substance with a microhardness of 98.59Gpa. Diamond is an allotrope of carbon, and its main component is carbon, which contains 0.02~4.8% of impurities. Its density is 3.15~3.53g/cm3. Its production area is very limited, and it is not only expensive but also extremely scarce.
Diamonds come in black, brownish-black, gray-black, etc., depending on their impurities. They are brittle and easy to crack along crystalline surfaces, and the larger the crystal, the more resistant it is to external forces. The measurement unit of a diamond is carat, and 1 carat = 0.2g.
Used for dressing grinding wheel.
Grinding and polishing difficult-to-process materials (such as hard alloys, gemstones, glass, stones, etc.).
The main mineral component of natural corundum is α-Al2O3, and its microhardness is 20.58Gpa, and its density is 3.93~4.00g/cm3. There are mainly three types of natural corundum in nature:
High-quality corundum (commonly known as gemstones) includes sapphire (containing titanium) and ruby (containing chromium), etc.
Ordinary corundum, black or reddish-brown.
Emery, which can be divided into green beryl emery and brown iron emery. It is a collection of crystal, and its hardness is relatively low.
Among the above three types of natural corundum, the first type is mainly used for jewelry, and the latter two can be used as abrasive paper, sand belt, and sand cloth rolls to manufacture grinding wheels, oilstones, abrasive paper, sand cloth, or micro-powder, grinding paste, etc.
Garnet has good crystal shape, and its microhardness is 13.33Gpa. There are many types of minerals belonging to garnet, but only iron-aluminum garnet is suitable for making abrasive paper, sand belt, and sand cloth rolls. Its mineral composition is: 3FeO.Al2O3.3SiO2, with a content of not less than 85~90%.
Quartz's chemical composition is SiO2, often mixed with Al2O3, Fe2O3, CaO MgO Fe2O3, etc. Its microhardness is 8.04 Gpa. Quartz minerals can be used as abrasive paper, sand belt, and sand cloth rolls, including vein quartz, quartzite, and quartz sand.
With the development of science and technology, the varieties of artificial abrasive paper, sand belt, and sand cloth rolls have reached dozens, and natural abrasive paper, sand belt, and sand cloth rolls have been replaced by more and more artificial ones due to their own defects.
Currently, except for natural diamonds and garnets, the usage of other types of natural abrasive papers, sand belts, and sand cloth rolls is very low.