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Magnetite quartzite tailings waste rock to produce sand and gravel technology for construction

Release date:2018-06-22  source:环球破碎机网  Browse times:720
      I. Introduction to technical equipment

The magnetite quartzite type iron tailings and waste rock are mainly composed of silicate minerals, and there are a large number of silicon oxide and aluminum oxide broken bonds on the surface, which is more likely to form a chemical bond with the metallurgical slag-based silicon-aluminum-based cementitious material than the original resources. . Magnet quartzite

Iron ore is mainly distributed in the Beijing-Tianjin-Hebei region and the Anshan-Benxi region, and there are also a small number of distributions in Shanxi, Shandong, and Jiangxi. At present, there are more than 20 billion tons of magnetite quartz tailings and waste rock in the Yanshan and Taihang mountains in Beijing, Tianjin and Hebei. The magnetite quartzite tailings waste rock production sandstone material can replace the sand and gravel produced by the mountain and the waste rock in the Beijing-Tianjin-Hebei region, so that the problem of large-scale stockpiling of tailings can be solved, and the exploitation of natural sandstone resources and the waste rock of the mountain can be reduced. The multiple problems caused by air pollution and smog can also alleviate the problem of extreme shortage of natural sandstone resources in some areas of China, and contribute to the realization of China's energy conservation and emission reduction targets. The flow chart of tailings production and construction sand is shown in Figure 1. The process flow of waste concrete to produce concrete coarse aggregate and construction sand is shown in Figure 2.

Fig.1 Schematic diagram of the process flow for the production and construction of magnet quartzite iron tailings

As shown in Figure 1, the magnetite quartzite type iron tailings slurry discharged from the concentrator is sieved by wet method to obtain coarse sand, medium sand and fine sand in accordance with GB/T14684-2011 "Building Sand Standard". A certain percentage of extra fine sand is produced for use by some special users. The proportion of solid matter in the remaining tailings slurry accounts for about 15%-20% of the total tailings in the original tailings slurry. After dewatering by pressure filtration, the filter cake is obtained, and the particle size is 95% less than 80 μm. The tailings mud is similar to the clay raw material used in the local production of sintered brick products, has a certain viscoplasticity, and can be sold to a local sintered brick factory as a raw material for producing sintered bricks. The filter-filtered wastewater is 100% comprehensively utilized, supplied to the concentrator as ore dressing water, or partially used for waste rock.

Wet processing production line. Compared with the exploitation of natural river sand, mountain sand or machine sand, this technology does not emit any waste, which can greatly reduce the dust pollution to the air.

Fig. 2 Schematic diagram of the process flow of waste concrete production of concrete coarse aggregate and construction sand
As shown in Fig. 2, the magnetite quartzite type iron ore waste rock is firstly crushed by the wet method, and then a plurality of magnetic pulleys are sorted, and a small amount of low-grade iron ore is sorted and supplied to the concentrating plant. Most of the remaining extremely weak magnetic waste rock enters the secondary wet crushing process. The crushed product was sieved by multiple wet processes to obtain three types of products. The first type is concrete coarse aggregates that meet the standards of GB/T14685-2011 "Construction Pebble, Gravel" and different grades. The second category is waste rock blocks with a particle size larger than the allowable size of the concrete coarse aggregate. This type of waste rock is returned to the secondary crushing process for re-crushing and sieving. The third category is tailings with a particle size smaller than the allowable particle size of the concrete coarse aggregate. Because of the full process wet operation, the tailings enter the fine screening multi-screening process in the form of tailings slurry. There are also three types of products in the fine screening multi-screening process. The first category is construction sands of various specifications in accordance with the GB/T14684-2011 standard "Building Sand Standards". The second category is gravel with a limit particle size larger than the size of the building sand but smaller than the concrete coarse aggregate. Some of this type of crushed stone can be sold to special users for the production of special building materials (such as concrete pipes, permeable bricks), and some of them are finely crushed and returned to the fine screening and multi-screening process. The third type of product is a tailings slurry in which the solid particles are 95% less than 80 μm. The tailings slurry is dewatered by pressure filtration and sold to the sintered brick factory, and the filter press wastewater is returned to the waste rock wet crushing process. The whole process of the process is free of waste water, waste slag and dust emissions, and it can greatly reduce the dust pollution to the atmosphere compared with the production of natural river pebbles and the production of concrete gravel aggregates.

Second, suitable for promotion of areas and areas

This technology is suitable for promotion in areas such as the Beijing-Tianjin-Hebei region and the Anshan-Benxi region, where magnetite quartzite-type iron ore is distributed in Shanxi, Shandong, and Jiangxi. Mainly used in the field of building materials.

Third, the project has been put into production

This technology has not only been promoted and applied in all mining companies affiliated to Beijing Miyun metallurgical Mining Co., Ltd., but also has been promoted and applied in most metallurgical mining companies in Miyun, and has held several classes through the tailings alliance in Tianjin, Hebei and Liaoning. And other places have been promoted and applied. In 2013, five mining enterprises under Miyun metallurgical Mining Company produced 28 million tons of tailings and waste rock aggregates, and more than 95% of them were sold to concrete mixing stations or prefabricated factories in Beijing. These tailings and waste rock aggregates can produce 12 million cubic meters of concrete, with a total output value of more than 4 billion yuan. Due to the use of the all-wet clean production technology, the 28 million tons of tailings and waste rock aggregate produced by Miyun metallurgical Mining Company in 2013 reduced the emission of nitrogen oxides to the atmosphere by about 5,000 tons (both in the mountains). Each kilometer of crushed stone consumes 1 kilogram of explosives, and each kilogram of explosives produces 500 grams of nitrogen oxides. It reduces the emission of 572,000 kilograms of rock dust particles with a particle size of less than one micron to the atmosphere. Producing 54.2 grams of rock dust particles with a particle size of less than one micron, equivalent to 542 tons, has made an important contribution to protecting the capital's environment.

4. Economic and technical indicators of technology (equipment)

The technology consumes the tailings and waste rock to produce aggregates, which has lower energy consumption and is competitive in terms of cost and sales price compared with the mountain.

 
 
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