| During the development process of mineral resources, large quantities of tailings will be discharged at the same time. Accordingly, they would cause serious pollution to environment, even threat human survival and development. Therefore, the conduct of tailings utilization has vital practical sense on improving mining-pollution and alleviating ecological stress. In this paper, refer to large accumulation of asbestos tailings in Shimian Country of Sichuan Province, We elaborate the research of asbestos tailings'hazards and their utilization, introduce related investigation of recovery of useful element-SiO2, which can be made for white carbon, and its production and application. Besides, we analysis advantages and disadvantages of white carbon's abstract from asbestos tailings, combine with the basis of previous studies, propose the cleaner production technology, which can be used for pick-up white carbon from asbestos tailings.Holding the concept of clean production, we spread out the overall design of production process, including selection of initial raw materials, determination of process conditions, improvement of process route, production of final silica and its by-products, and disposal and emission of'Three Waste'in the process, which of all should follow the requirements of clean production strictly.In the issue, according to the feature of high magnetite content of asbestos gangue in Sichuan Province, we use three sections of processes which was consist of solid-liquid separation process of silicon and magnesium, magnetic separation technology combined with second acid leaching and Magnetic seed sorting technology used to remove Iron. We expand the technology about clean production of production white carbon from asbestos tailings. Main contents and conclusions are as following:1. Via chemical analysis and XRD identify,we master the chemical composition of asbestos tailings and mineral composition,start asbestos tailings'decomposition process in acid medium,find the optimization conditions of Silicon, magnesium's solid-liquid separation process conditions by single-factor experiment. The results show that the add of co-solvent suitably could increase the leaching efficiency of magnesium significantly, in these optimum conditions, the leaching efficiency reached up to 98.76%.2. After acid leaching, there're many impurities in acid leaching residue. The main impurities Iron could be enriched by the form of magnetite. Regarding to this phenomenon, laboratory has designed electromagnets–blender by itself, to analysis the influences Iron's removing on reaction temperature, - time, Concentration of hydrochloric acid and Solid liquid ratio, ensured the best prerequisites of removing Iron. Under these conditions, the rate of prolapse would achieve 94.41%.3. Application of the magnetic separation technique to replace chemical reagents in an innovative way to carry on purify technology, we study the effects on Iron's removing with magnetic seed and the dispersant's species and quantities. With the best magnetic separation in optimum conditions, we could get the rate of Iron prolapse reaching 78.42%.4. Yielding of silica products under optimal conditions, purity of SiO2 is 91.23%, BET surface area reach up to 236m2/g, the particle size range of 0.1~1μm, the whiteness can be 83.7, which meets the quality requirements of A class standard HG/T3061-1999.5. This clean production process could make the recovery of SiO2 in asbestos tailings reach 94.45%, With asbestos tailings(1 ton) has been disposed, would produce comprehensive benefits reaching to 873.2 Yuan. The whole process bring about cleaner production ,obvious economic , environmental and social benefits.The process is simple, easily to handle, short running duration and low investment costs, which is the technology of clean production's specific application with small investment, low pollution, and high-yield, and is the specific implementation of the circular economy, it has a bright prospect for industrial applications. |
PDF Full Text Request