Kaolin is an important non-metallic mineral material, it is not only traditional industries need raw materials, light industry, etc., is the basic material of modern industrial development, is the 21st century green materials. With the continuous development and utilization of mineral resources, a large number of kaolin tailings are produced, most of which are piled up and abandoned, which not only occupy a large amount of land, but also seriously pollute the environment [1-2] . Polyaluminum chloride, iron (a PAFC) is a new complex inorganic polymer flocculant, coagulant having good because such coagulation effect, a wide source of raw materials, inexpensive, post-treatment was less residue in water, etc., caused by Great attention in the water treatment industry [3-6] . In this experiment, Suzhou kaolinite tailings was used as raw material to prepare composite inorganic polymer flocculant polyaluminum ferric chloride (PAFC) by high temperature roasting, acid leaching, hydrolysis and polymerization, and used for industrial wastewater treatment. Satisfactory results have been obtained, which has found a new way for the comprehensive utilization of kaolin tailings and the treatment of industrial wastewater. First, the experimental part (1) Experimental materials Suzhou kaolin tailings: particle size ≤ 200 mesh, white or light yellow solid powder, chemical analysis results (wt%): SiO 2 , 61.37; A1 2 O 3 , 30.12; Fe 2 O 3 , 6.31. Hydrochloride: industrial products, 35% to 37%, Wuxi Jiangsu chlor-alkali plants; calcium oxide, sodium carbonate, silver sulfate, mercury sulfate, chromium potassium heavy, ferrous sulfate, non-ortho Rollins, ammonium ferrous sulfate and the like are Chemically pure or analytically pure reagent. (2) Preparation of polyaluminum ferric chloride (PAFC) It is known from the composition content of Suzhou kaolin tailings that the iron-aluminum component can be dissolved by acid under certain conditions, and the iron salt and aluminum salt solution can be obtained, and the pH value can be adjusted to hydrolyze and polymerize, thereby preparing a composite inorganic high. A molecular flocculant polymerizes aluminum chloride iron (PAFC). The technical route of PAFC preparation is shown in Figure 1. The effects of calcination temperature, hydrochloric acid mass fraction, liquid-solid mass ratio, acid leaching temperature and acid leaching time on the total dissolution rate of iron and aluminum were investigated by single factor experiment (refer to Fe 2 O 3 in kaolin tailings). The total dissolution rate of A1 2 O 3 , the same below), to determine the better dissolution reaction parameters; based on the selection of reasonable dissolution reaction parameters, determine the appropriate hydrolysis polymerization conditions by experiment, use a homemade PAFC to Suzhou leather Co., Ltd. adjusted the turbidity, chroma and CODCr removal rate of wastewater in the pool to evaluate the optimal iron-aluminum hydrolysis polymerization conditions. (3) Coagulation test Taking a certain amount of water quality in the regulation pool of Suzhou Leather Co., Ltd. for coagulation test, the water quality indicators are shown in Table 1. Take 500mL of wastewater in the beaker, then add the same amount (1.OmL / L) of flocculant in the beaker, stir rapidly (120r / min) for 3min, then slowly stir (40r / min) for 12min, after standing for 12min The supernatant was taken to determine turbidity, color and CODCr. Second, the results and discussion (1) Selection of influence parameters of total dissolution rate of iron and aluminum in kaolin tailings 1. Effect of calcination temperature on total dissolution rate of iron and aluminum in kaolin tailings The calcination time of kaolin tailings was controlled for 2 h. The effect of different calcination temperatures on the total dissolution rate of iron and aluminum in kaolin tailings was investigated in the range of 550-750 °C. The experimental results are shown in Fig. 2. It can be seen from Fig. 2 that the total dissolution rate of iron and aluminum in kaolin tailings increases with the increase of calcination temperature, and reaches the maximum at around 650 °C. After that, the dissolution rate decreases rapidly with the increase of temperature. This is due to the conversion of metakaolin at high temperatures to silicon spinel, mullite, etc., which are extremely insoluble in acid. Therefore, the calcination temperature of the kaolin tailings should be controlled at 600 to 700 °C. 2. Effect of hydrochloric acid mass fraction on total dissolution rate of iron and aluminum in kaolin tailings The acid leaching time was 5h, the acid leaching temperature was 85°C, and the liquid-solid mass ratio was 3:1. The effect of different hydrochloric acid mass fractions on the total dissolution rate of iron and aluminum in kaolin tailings was investigated. The experimental results are shown in Fig. 3. . It can be seen from Fig. 3 that as the mass fraction of hydrochloric acid in the leachate increases, the total dissolution rate of iron and aluminum increases. When the mass fraction of hydrochloric acid exceeds 15%, the total dissolution rate of iron and aluminum increases with the concentration of hydrochloric acid, and the dissolution rate instead decline. This is due to an increase in the amount of hydrochloric acid volatilization under non-sealed conditions. Therefore, the mass fraction of hydrochloric acid in the leachate should be controlled at 15%. 3. Effect of liquid-solid mass ratio on total dissolution rate of iron and aluminum in kaolin tailings The concentration of hydrochloric acid in the leachate was 15%, the acid leaching time was 5h, and the acid leaching temperature was 85°C. The effects of different liquid-solid mass ratios on the total dissolution rate of iron and aluminum were investigated. The experimental results are shown in Table 2. It can be seen from Table 2 that the total dissolution rate of iron and aluminum increases with the increase of liquid-solid mass ratio, the liquid-solid mass ratio increases, the solid-liquid contact opportunity increases, and the reaction speed increases, so the total dissolution rate of iron-aluminum increases. However, after the liquid-solid mass ratio exceeds 3:1, the total dissolution rate of iron-aluminum is not obvious. Therefore, the liquid-solid mass ratio should be controlled at 3:1. 4. Effect of acid leaching temperature on total dissolution rate of iron and aluminum in kaolin tailings The concentration of hydrochloric acid in the leachate was controlled to be 15%, the liquid-solid mass ratio was 3:1, and the acid leaching time was 5h. The effects of different acid leaching temperatures on the total dissolution rate of iron and aluminum were investigated. The experimental results are shown in Fig. 4. It can be seen from Fig. 4 that when the acid leaching temperature is lower than 85 °C, the total dissolution rate of iron and aluminum increases with temperature, but when the acid immersion temperature exceeds 85 °C, the total dissolution rate of iron and aluminum decreases rapidly. This is because the loss of hydrochloric acid volatilization is greatly increased under non-closed conditions, which accelerates the hydrolysis rate of Fe3+ and Al3+, resulting in a decrease in the concentration of Fe3+ and Al3+ and a decrease in the total dissolution rate of iron and aluminum. Therefore, the optimum acid immersion temperature is preferably controlled at about 85 °C. 5. Effect of acid leaching time on total dissolution rate of iron and aluminum in kaolin tailings The concentration of hydrochloric acid in the leachate was controlled to be 15%, the liquid-solid mass ratio was 3:1, and the acid immersion temperature was 85 °C. The effect of different acid leaching time on the total dissolution rate of iron and aluminum was investigated. The experimental results are shown in Fig. 5. It can be seen from Fig. 5 that the total dissolution rate of iron-aluminum increases with the prolongation of acid leaching time, but when the acid leaching time exceeds 5h, the total dissolution rate of iron-aluminum decreases. This is because the loss of hydrochloric acid volatilization is greatly increased under non-closed conditions, which accelerates the hydrolysis rate of Fe3+ and Al3+, resulting in a decrease in the concentration of Fe3+ and Al3+ and a decrease in the total dissolution rate of iron and aluminum. Therefore, the acid leaching time is preferably 5h. (II) Selection of parameters for iron-aluminum hydrolysis polymerization The Ca(OH) 2 and Na 2 CO 3 solutions were used as the telogen, and the effects of hydrolysis polymerization temperature, pH value and reaction time on the polymerization were investigated. The results are shown in Table 3. The polymerization effect was evaluated by product stability and turbidity, color and CODCr removal rate of wastewater. It can be seen from Table 3 that the product obtained by using Ca(OH) 2 solution as a telogen has good stability, and the maximum removal rates of turbidity, chroma and CODCr are 78.23%, 87.56% and 78.95%, respectively. The hydrolysis polymerization conditions are: a hydrolysis polymerization temperature of 55 to 65 ° C, a polymerization pH of 2 to 3, and a reaction time of 3 hours. Third, the conclusion (1) The optimum dissolution conditions for kaolin tailings are: control roasting temperature 600-700 ° C, hydrochloric acid mass fraction 15%, liquid-solid mass ratio 3:1, acid leaching temperature 85 ° C, acid leaching time 5 h, kaolin tail The total dissolution rate of iron and aluminum in the mine can reach more than 90%. Under the optimal dissolution conditions, the optimal hydrolysis polymerization conditions of iron-aluminum are as follows: Ca(OH) 2 solution is used as a telogen, hydrolysis polymerization temperature is 55-65 ° C, pH is 2 to 3, and reaction time is 3 h. The prepared composite inorganic polymer flocculant PAFC has good stability, and the turbidity, chroma and CODCr removal rate of the wastewater in the leather industry are 78.23%, 87.56% and 78.95%, respectively. (2) Preparation of composite inorganic polymer flocculant polyaluminium chloride (PAFC) by using kaolin tailings. The process is simple, the production conditions are easy to control, the source of raw materials is wide, and the production cost is low, which provides comprehensive utilization of kaolin tailings. A new way. references [1] Zhang Zhongfei, Chen Likun, Li Xinchang, et al. Efficient comprehensive utilization of Suzhou kaolin tailings[J].Non-metallic Mines,2008,31(5):44-46. [2] Huang Zili, Hu Yuehua, Jiang Xinfu, Preparation of Polyaluminium Chloride by Using Peri-Production Hydrochloric Acid and Inferior Kaolin[J]. Chemical Environmental Protection, 2002, 22(5): 284-286. [3] high gem, in Hui, YUE Qin Yan, et Study prepared PAFC flocculant coal gangue [J] Environmental Sciences, 1996,17 (4): 62-66. [4] Hu Junhu, Liu Xiyuan, Li Xiaohong, et al. Synthesis and Application of Composite Flocculant Polymerized Aluminum Ferric Chloride (PAFC)[J].Environmental Chemistry,2007,26(1):35-38. [5] Bekri-Abbesa I, Bayoudhb S, Bakloutic M. A technique for purifying wastewater with polymeric flocculant produced from waste plastic [J]. Desalination, 2007, 204: 198-203. [6] Poulin E, Blais JF, Mercier G. Transformation of red mud from aluminum industry into a coagulant for wastewater treatment [J]. Hydrom etallurgy, 2008, 92: 16-25. Steel Pipe And Cold Drawn Shaft Rubber Wedding Rings,Rubber Ring,Custom Rubber Rings,Cheap Rubber Rings Qufu Zhuoyue Heavy Industry Science&Technology Co., Ltd , https://www.zhuoyueindustry.com