The cement used in traditional cement-bonded concrete filling materials is generally 425 ordinary Portland cement, the dosage is 150~300kg/m3, the water-cement ratio is about 1.2~1.3, the compressive strength of 28d concrete is 5.0~10.0MPa, and the cement is in the cementing filling cost. Accounted for 30% to 60%.
Therefore, one of the main ways to reduce the cost of cementing filling is to find a substitute for cement and reduce or even eliminate the amount of cement in the filling slurry.
Blast furnace slag is a byproduct of the smelting of pig iron. The activity of the slag is mainly determined by its structure, and its structure is roughly regarded as a polymer of a crystalline phase and a glass phase. The glass phase of the slag is the active component and the crystalline phase is the inert component. All of the slag has a large glass phase content and its activity is high. Most of China's slag has a vitreous content of more than 80%, and CaO/SiO2 is about 1.0, indicating that blast furnace slag is a good substitute for cement.
Pulverized coal power plant ash is discharged from an industrial waste, it is ground to certain fineness of pulverized coal suspended after a high temperature of 1200 to 1500 degrees Celsius by the combustion in the pulverized coal furnace, or the coal contained in the clayey Minerals undergo decomposition, oxidation, melting and other changes, forming fine droplets under the action of surface tension, and rapidly cooling to form fine spherical particles with a particle size of 1 to 50 microns when discharged outside the furnace. The combustible combustibles are collected together by a dust collector or discharged from a water flow conduit to a ash storage yard. Most of the fly ash is a glass phase, and there are a small amount of unburned carbon and some crystalline minerals. The crystal minerals are mainly quartz and mullite. The CaO/SiO2 ratio in fly ash is about 0.1, which is the main reason why the activity of fly ash is much smaller than that of slag. At present, fly ash can partially replace cement in filling cementitious materials. In Canadian filling mining, the amount of fly ash has reached 60%, making it a low-cost filling gelling material for mines in Canada.
The Vicenti mines owned by Outokumpu of Finland have replaced 90% of Portland cement with blast furnace slag and 70% of cement with fly ash in other cases, Kidd Creek, Canada. The test and application of the mine show that the blast furnace slag or fly ash replaces at least 30% to 60% of ordinary Portland cement. Changsha Institute of Mining and Shandong Aluminum companies, direct use of alumina production waste - red mud was added a small amount of fly ash and intensification of active agent prepared at a concentration of about 60% of the filling slurry pressurizing pump To fill the stop, get a good quality filling. The direct filling cost is less than 40 yuan per cubic meter, of which the raw material cost is only 9 yuan per cubic meter. Compared with traditional cementing filling, the raw material cost is only 1/5~1/10 of the cement cement filling, and the filling cost is only the same strength cement. 1/2~1/3 of cemented filling. A large number of tests have shown that cement-free cementation filling is completely feasible, and its economic and social benefits are very significant.
After the Zhangmayu Iron Mine replaces part of the cement with blast furnace slag fine grinding products, the production cost of cementation filling is greatly reduced. The blast furnace slag of the iron plant near the mine is transported to the mine slag silo by dump truck, and its volume is 24 cubic meters; then it is evenly discharged into the belt conveyor through the vibration feeder, and automatically measured by the microcomputer multifunctional electronic belt scale. Add water to the ball mill for fine grinding; the fineness of the control module is -0.074mm, which accounts for more than 60%. The finely ground slag is distributed by two 100mm pipes (controlled by pipe clamp valve, one open and one ready) to the double shaft mixer. It is mixed with tailings and cement to form a slurry, which is sent to the underground goaf for cementation filling. Two beneficiation plant tailings slurry was dehydrated, obtaining a water content of about 20% wet tailings, stirred by a biaxial mixer and a high-speed stirrer two mechanical strength (activation), and the tailing ratio of 1: 1 cement It is mixed with finely ground water slag and water to make a high-concentration cemented filler of about 70%, and is filled into the goaf by means of pipeline self-flow conveying method to form a filling body with good standing and integrity. The strength of the filling body meets the requirements of various technical parameters, which can meet the requirements of the column of the mining back room. The mine has a production capacity of 500,000 tons/year. Due to the use of blast furnace slag, the annual cement consumption is 14,400 tons.
Blast furnace slag and fly ash are waste materials in industrial production, and if they are not used effectively, they are easily discarded and destroyed. Therefore, after researching and successfully testing that blast furnace slag and fly ash can become cement substitutes, these problems are solved.
Water Tube Biomass Steam Boiler
Water Tube Biomass Steam Boiler Features
1. Independent air chamber structure makes the air volume adjustment between the air chambers sensitive and reliable, even air distribution.
2. Boiler proper adopt membrane wall structure, which increased the boiler heating area. Tight sealing avoid wind leakage, low the heat loss, increase the boiler thermal efficiency.
3. 1-8 tph boiler is package type delivery from factory, which can greatly shorten the installation time.
Water Tube Biomass Boiler,Water Tube Biomass Fired Boiler,Water Tube Biomass Fired Steam Boiler,Industrial Water Tube Biomass Boiler,Automatic Water Tube Biomass Boiler
Henan Yuanda Boiler Co., Ltd. , https://www.industrysboiler.com