| Kaolinite-type pyrite is a kind of pyrite existing in kaolinite sediments,with the proportion of pyrite ranging from 25%to 30%and the proportion of kaolinite ranging from 70%to 75%.In China,kaolinite-type pyrite is extremely abundant,accounting for about 40%of total pyrite reserves.A large number of tailings have been produced during the mining and processing of kaolinite-type pyrite.The main component of tailings is kaolinite.At present,tailings have not been utilized as resources and can only be piled up,which not only occupies a large number of land resources,but also causes serious damage to the local ecological environment.Therefore,the active research on the resource utilization technology of the tailings has significant environmental protection significance and provides ideas for the resource utilization of kaolinite-type pyrite flotation tailings.In this thesis,the kaolinite-type pyrite flotation tailings were taken as the research object,and the chemical composition and phase composition of the tailings were analyzed by modern analytical testing techniques.On this basis,the kaolinite-type pyrite flotation tailings were utilized to the preparation of 4A zeolite,PAC and porcelain tiles.The feasibility of the three resource utilization technologies was studied systematically.Characterization analysis and performance testing were performed on each product.The main conclusions are as follows.?1?The main phase of kaolinite-type pyrite flotation tailings was kaolinite,which contains a small amount of anatase and pyrite.The main chemical compositions were SiO2,Al2O3,Fe2O3,TiO2 and SO3.?2?Using the tailings as a raw material,calcination at 800°C for 2 h could obtain highly reactive calcined kaolin.The concentration of SO2 in the sulfur-containing tail gas produced during the calcination process far exceeded the emission standard of atmospheric pollutants.The desulfurization rate of NaOH as desulfurizers reached 97.99%.The concentration of SO2 in the tail gas after desulfurization was 31.51 mg/m3,which was obvious lower than the concentration requirements of relevant national standards.?3?Based on the best ratio of raw materials?calcined kaolin 5 g,NaOH 6.5 g,H2O 65 mL?,the raw materials were stirred and sonicated,and then hydrothermally reacted at 110°C for 3h to obtain 4A zeolite.The synthesized 4A zeolite had a relative crystallinity of 40.77%and a calcium ion exchange capacity of 210.32 mg CaCO3·g-1.The static water adsorption capacity was 28.43%,but the synthesized 4A zeolite had no photocatalytic activity.Based on the optimal hydrothermal synthesis conditions,TiO2 was doped into the calcined kaolin and subjected to hydrothermal synthesis.This produces a photocatalytic 4A zeolite,i.e.,a photocatalyst of zeolite supported TiO2.?4?Calcined kaolin and 4 mol/L hydrochloric acid solution?the ratio of solid and liquid was125 g/L?were reacted at 95°C for 3 h to obtain aluminum leaching solution with Al2O3leaching rate of 95.83%.The leaching process was in accordance with the interior diffusion control model.8 g of calcium aluminate was added to the aluminum leaching solution at90°C,and after 4 h of reaction,the solid and liquid were separated,and the filtrate was dried to obtain a solid PAC.It had an Al2O3 content of 29.90%,a basicity of 67.14%,a pH of 3.8,and an insoluble content of 0.6%.?5?The optimum firing temperature for preparing porcelain tiles from the tailings was1250°C.The determined bottom material formulation was 35%feldspar,40%quartz,and 25%tailings.The upper material formulation was 40%feldspar,40%quartz,20%kaolin.The breaking strength of porcelain tile products reached 1324.32 N,the modulus of rupture was35.32 MPa,and the water absorption rate was 0.22%.In this thesis,the 4A zeolite,PAC and porcelain tiles products which preparated from the kaolinite pyrite flotation tailings as raw materials have reached the national standards.It could be industrialized in theory,which provided reference for the resource utilization of kaolinite pyrite flotation tailings. |
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