The Preparation And Application Of Poly-alumina Iron Flocculant Based Red Mud

Considering that the harmfulness of printing and dyeing wastewater and red mud forenvironment has hindered the development of industry, this paper is concerned with a methodbased on waste control waste. In this paper, an inorganic polymeric coagulant was preparedby ferro-aluminium extracted from red mud to deal with the printing and dyeing wastewater.With this method, the recovery and reutilization of red mud became possible. It plays animportant role in controlling environment pollution and promoting the development ofindustry, creating great social and economic value.In the study, the flocculant was prepared by use of red mud as raw material through aciddip and polymerization. In the acid leaching experiments, the red mud was modified to leachout aluminum and iron, getting aluminum-iron leaching liquid. X-ray analysis indicated theexisting form of ferro-aluminium in the red mud. The factors which have an influence on themodification of red mud were selected. The orthogonal experiment was used to analysis theinfluence of each factor on acid leaching and to determine the optimum processparameters.The alkali was added to aluminum-iron leaching liquid to get the polymericaluminum ferric chloride (PAFC). The optimal process parameters of flocculant synthesiswere evaluated according to the turbidity removal rate of the simulated high turbidity water.The treatment effect of PAFC and PAC under the optimum dosage and pH werecompared on treatment of the industrial wastewater of a printing and dyeing mill in Zibo andthe results are as follows. With the dosing of PAFC180mg/l, the removal rate of SS, turbidityand color reached up to94.51%,85.26%and70.56%respectively and with the same dosage,the removal rates of PAC were lower than that of PAFC. Between the pH value of6~10,PAFC has an excellent coagulating effect and the suitable range of pH of PAFC is wider thanthat of PAC.The surface structure of PAFC was observed under electron microscope. PAFC is ahigh-molecular polymer formed by chain molecules and it has high subnetted degrees andstable morphology. X-ray analysis indicated that PAFC is not a mixture of Al and Fe, but anamorphous polymer. The XRD spectrum indicated that PAFC is aluminum ferric polymerswith polyhydroxy federation. By using the familiar knowledge of coagulation mechanism and coagulation morphology,the coagulation mechanism and coagulation morphology of PAFC were preliminarydiscussed.