Preparation Of Calcium Silicate Board By The Phosphorus Slag And Phosphate Tailings

Since the reform and opening up, with the rapid development of China’s industrialization, mineral resources are a heavily mined, mineral byproducts are piled up like a mountain, had been triggered a series of ecology, safety and environmental problems. China is rich in phosphate resources, but more than 80% was low-grade phosphate rock. Phosphate industry produces large amounts of phosphorus tailings, phosphorus slag in the mining, production process. The research on phosphate industrial solid waste as the main raw materials to prepare of building materials.The subject use phosphorus slag, phosphorus tailings as the main raw material, to prepare D0.8, D1.3 two categories of calcium silicate board products, after the experimental material was analyzed systematically, Select pulp molding to prepare test specimens, Limited by the uniform design to design experiments ratio, quadratic polynomial regression to obtain optimum ratio, determine the best autoclave curing system, the main contents are described as follows:1、Determination of phosphorous slag as a cementitious material chemical properties, compared to explore the influence of level S95, S105 grade phosphorus slag as a cementitious material on the water consumption, fluidity, setting time and activity index of mortar, by the improvement of performance and the energy consumption of the chemical phosphorous slag milling to determine the level of phosphorous slag milling to S95 is the best.2、Phosphate tailings research as an inert filler material to prepare calcium silicate board,Limited by the uniform design to design experiments ratio, quadratic polynomial regression to obtain optimum ratio, test on the density, mechanical properties of the best ratio specimen, change the autoclave curing system, and determine the best system for steam curing insulation 6h at 180 ℃.The flexural strength of D0.8 class products are<5MPa,the flexural strength of D1.3 class products are<7MPa,the mechanical properties failed to achieve the desired effect, and add the amount of phosphate tailings are less than 5%,industrial waste utilization rate is low, so phosphorus tailings as inert filler preparation of calcium silicate board is not feasible.3 、 Calcination and grading treatment of phosphate tailings, as well as photomicrographs, apatites, dolomites and quartzs glued together with each other could be found, the dissociation of minerals grain is not sufficient, by calcination and crushing making mineral particle separation, then through airflow classification grading rich phosphorus product, calcium and magnesium-rich products, silicon-rich product out. Respectively at 800 ℃, 850 ℃, 900 ℃ and 1000 ℃ calcine tailings and analyze the calcined samples photomicrographs, so the best calcination temperature is obtained.Under the conditions of a frequency of 15 Hz, calcined at this temperature in the tailings material crushing, so that different mineral particles are separated; And then according to eight frequencies between 5-40 Hz in descending order,the tailings materials crushed by airflow classification were grading. The graded material for each frequency corresponding is tested by XRD diffraction, and the XRD pattern for the whole pattern fitting is quantitative analysis. The results show that,850℃ is the best calcination temperature, calcined phosphate tailings were completely separated at this temperature and apatite particle structure is not completely collapsed. Within a range of 5-25 Hz frequency is phosphorus-rich product, less than 5Hz is silicon-rich product, more than 25 Hz is calcium and magnesium-rich product.4、The research of preparation of calcium silicate boards by calcining the fractionated mine tailings is a research that uses the fractionated mine tailings which are rich in silicon and calcium-magnesium product and phosphorous slag as the main crude material, design the mix proportion by limited and equaliy distributed method,use regression analysis to decide which is the best mix proportion,alter the length of the process of steaming caring thermal insulation,measure the effect of the length of thermal insulation on the products’ performances. In this research,the best mix proportion and the length of thermal insulation are decided and the products’ performances are systematically tested. The results indicate that 6 hours’ is the best length of thermal insulation,under 180℃.The flexural strength of the products are >5.5MPa for category D0.8,and >9.5MPa for category D1.3.Its incombustibility hit the level A1 and thermal conductivity is <0.20W/m·K.During the process of calcining the phosphorous slag and the fractionated preparation of calcium silicate boards,fractionated product which is rich of phosphorous can be used as phosphorous chemical industry crude material,and the one rich in magnesium and silicon can be utilized in the manufacturing of boards. In this way the mine tailings are made full use. Meanwhile combined with the phosphorous slag, it maximize the utilization of the wastes which is produced in phosphorous chemical industry. Moreover,this kind of board is light in weight and keeps warm,therefore it is competitive in the market.