What are the mine filling materials?
1 ) Filling aggregate There are many kinds of filling aggregates used in mines at home and abroad. Most of them are based on the actual conditions of the mine, and the materials or industrial wastes with wide sources, low cost, stable physical and chemical properties, non-toxic, harmless and skeleton function are used as filling aggregates. In the 1950s, China used extensively excavated waste rock or open pit mining to remove waste rock for filling. For the 60s and 70s, the application of mountain sand, river sand, Gobi aggregate, etc. as aggregates for concrete cementing or The fine sand such as river sand and de-clay tailings is filled or filled with aggregate, and the non-cemented filling or cementing filling of water sand is carried out by two-phase flow pipeline transportation; after the 1980s, new filling such as high-concentration full tailings cement filling is completed. The successful test of the technology, the complete tailings without classification and de-sludge treatment has become the most suitable filling material for development and application prospects. The filling material should be inert material, free of volatile harmful gases, and the sulfur content should not exceed 5 to 8% to prevent high temperature and sulfur dioxide, and deteriorate the underground atmosphere or cause underground fire. The maximum block size of dry filling materials generally does not exceed 200-300 mm; when filling with a throwing machine, the maximum block diameter is less than 70-80 mm; when using wind power, the maximum particle size is less than one-third of the pipe diameter. Generally no more than 50mm. Water-sand filling and cement-filling aggregates require chemical stability, and the particles themselves must have a certain strength and good permeability. The particle size of mountain sand, river sand, rod scrub and water quenching slag is much larger than that of tailings. The maximum particle size during transport is less than one-third of the diameter of the pipe, and particles close to one-third of the pipe diameter are not suitable. More than 15%. (1) tailings Tailings are the most commonly used metal filling aggregate mines, sometimes also known as tailings, after the mine mined ore through crushing beneficiation process, a useful component selected from finely ground rock particles, the remaining slag called tail The ore, that is, the waste discharged in the form of a slurry after ore dressing. (2) Smelting furnace slag The smelting slag is used as the filling aggregate, and the main purpose is to use the cementing performance of the smelting furnace slag after grinding, to replace part of the cement on the one hand, and to solve the environmental pollution problem caused by the smelting slag surface accumulation on the other hand. Most of the mines used for filling slag in China use blast furnace iron slag and copper and nickel smelting slag without fine grinding. For example, Daye Nonferrous Metals Company Tonglushan Copper Mine uses copper water quenching slag as filling material, Jinchuan Nickel smelting flash slag is used as a filling aggregate in the coarse aggregate filling system of the non-ferrous metal company Longshou Mine. (3) rod matte, wind sand and impact sand Rod sanding is a filling aggregate that has been crushed and rod milled into a grain-level composition to meet the requirements of mine filling. Because of its simple processing method, it is still favored by many mines despite its high processing cost. The wind sand is a natural fine sand naturally collected. For example, in the desert area, it is an ideal filling material. The particles are in the shape of beads, similar to millet, and 90% of the composition is quartz sand. Impact sand is fine sand formed in the ancient river bed, and can also be used as filling aggregate. In addition, river sand, lake sand, sea sand, etc. can be used as filling aggregates. (4) Waste stone Most mines use waste rock (including coal gangue) as close to the well as possible, and directly backfill it in the goaf. There are also some foreign mines that carry out rod grinding or crushing of waste rock. Generally speaking, the maximum particle size of rod grinding stone is 5mm. The broken waste stone depends on the different needs of each mine. It is reported in the report -25mm, -33mm, - 75mm, -100mm, -250mm, etc. Therefore, whether or not the waste rock is broken or broken depends on the specific requirements of the mine for the filling materials. (5) Industrial solid waste Utilization of industrial solid wastes (eg phosphogypsum, etc.) as filling aggregate backfill underground, we can solve the problem of mine filled with aggregate sources, while addressing the significant solid waste ground stacked the environmental pollution, economic, social and environmental benefits . However, whether the solid waste can be used as a filling aggregate and as a filling ratio when filling the aggregate must be confirmed by experimental research. 2 ) Cementitious materials and substitutes The most widely used filling gelling materials at home and abroad are ordinary Portland cement (commonly used 32.5 cement, commonly known as 425 cement), in addition to some cement substitute materials such as slag, fly ash and so on. (1) Cement The main chemical components of Portland cement are CaO (64~67%), SiO 2 (21~24%), Al 2 O 3 (4~7%) and Fe 2 O 3 (2~4%). In the cemented body, the cement undergoes a hydration reaction, and the aggregates are cemented together to form a solidified body. (2) Fly ash Fly ash is collected from the pulverized coal boiler flue gas of power plant to a fine powder, is also known as fly ash (fly ash), which is similar to the high aluminum clay component, it is present mainly in the vitreous state. At home and abroad, the performance of fly ash has been extensively studied. A lot of experimental work has been done on the use of fly ash instead of some cement as gelling agent. Some mines have added fly ash to the filling material to improve filling. Body strength and replace some cement with fly ash. In high concentration or paste filling slurry, the presence of an appropriate amount of fly ash can reduce pipe resistance and improve the pumping performance of the paste. (3) Water quenching furnace slag Smelter metal mining enterprises, industrial waste which is usually copper smelting slag, zinc, lead and other metal production discharged from the furnace at a high temperature slag, and then rapidly cooled so that the particulate is made by water quenching, then The SiO 2 in the slag exists in a vitreous state. The vitreous SiO 2 has metastable and reactive activity, and the granular water quenching slag is crushed and ground to a fineness of a specific surface area of ​​the cement (about 3,000 cm 2 ·g -1 ) to be used as cement. Substitute use. Glass fiber winding yarn is mainly used as electrical insulation material, industrial filtration material, anti-corrosion, moisture-proof, heat insulation, sound insulation, shock absorption material. It can also be used as a reinforcing material to make reinforced plastics (see color picture) or reinforced rubber, reinforced plaster and reinforced cement products. 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