Mineral powder is rock flour (< 600 ?m) produced by fine grinding of different minerals and rocks (usually carbonate strata) and industrial waste at hammer, ball or roller mills, as well as at disc grinders. The process of mineral power production at impactors is identical to the process of coal dust production at power stations. There also can be used tangential hammer mills, and blowbars – are working parts of grinding equipment. Working parts of disc grinders and roller mills are made of wear resistant cast iron and steel.
Mineral powder is actively used in preparing asphalt and asphalt-concrete mixtures for road construction, as inert and functional fillers which reduce the prime cost of materials for construction roadways and improving their quality (by increasing elasticity, strength and wear resistance). Additives of mineral powders to asphalt and asphalt-concrete mixtures increase the lifecycle of the roadway sufficiently and allows cost saving during its following operation.
According to classification applied in the Russian Federation, mineral powder for asphalt and asphalt-concrete mixtures (GOST 52129-2003) are divided into two main brands: MP-1 and MP-2:
- Mineral powder of MP-1 brand is produced of carbonate strata and can be either non-activated (for adding into organic mixtures used as animal feed and soils deoxidization), or activated with adding surface active agents or grinded bituminous material for preparing asphalt mixtures.
- Mineral powder of MP-2 brand is produced on non-carbonate rock, as well as of industrial secondary waste – smelter slag, furnace dusts from thermal power plants, cement furnace dust and other process waste. It is subject to full activation with the treatment of special grinded bituminous material and can be used only for preparing asphalt mixtures.
The road construction industry used more than a half (50%) of mineral powder produced in the Russian Federation. The consumption volume grows every year in compliance with growing scope of construction, tightened requirements for road quality and application of progression forms of using roadways like lifecycle contracts.
The second most important consumer of mineral powders (20%) are manufacturers of rolled roofing material.
The third area of application of mineral powders again connected with construction industry is aggregate industry. Here mineral powder is used as a filler material or finely divided filler.
The most traditional area of application of lime non-activated mineral powder is soil deoxidization during agrochemical procedures in agriculture. Nowadays, the consumption rate of mineral powder in this industry is declining due to reduce of state government allowance.
The top quality mineral powder is produced by grinding marble and marble carbonate rock. The manufactured mineral powder has its own brand name “microcalcite” or “grinded marble”. It is produced in several types – 2,5, 10, 40, 60, 80, 160, 315 and 500 ?m and is characterized by whiteness, i.e. to correspondence to certain reference white colour. The whiteness of microcalcite reaches 98%.
According to whiteness, the areas of application of microcalcite are rather diverse.
It is used in production of the following materials:
- White dry mortars
- Paints and varnishes
- Top-quality paper
- Rubber technical goods
- Cleaning powders and pastes
Other different rocks can be grinded for industrial purposes apart from carbonate strata:
- Hematite and barites for manufacturing weighting agents;
- Soap stone for manufacturing antifriction lubricators.
Nowadays total scope of industrial capacity of the Russian Federation for production of mineral powders is fully loaded, whereas the lack of mineral powder, especially high-tech industries (microcalcite and hard minerals) is made up by importing.