Xia Shibin

Phosphate removal of acid wastewater from high-phosphate hematite pickling process by in-situ self-formed dynamic membrane technology

Phosphate removal from pickling milling wastewater of high-phosphate hematite mineral by in-situ self-formed dynamic membrane reactor (DMR) developed with raw and activated red mud (RM-raw and RM-a) was studied in this paper. The results indicated that RM dosage, velocity gradient of the mixer (G value), reaction time (t), and pH were main effects on phosphate removal. The pH of the actual mineral processing wastewater is 2.50 similar to 2.53 while the phosphate concentration is 98.85 mg/l. After the treatment, the removal rate of phosphorus with RM-raw and RM-a can reach 94.33% and 99.72%, respectively, with the dosage of 23.00 g/l and 20.00 g/l, respectively. Correspondly, effluent pH was respectively 8.12 and 3.06, and both turbidity could reach the effluent requirement. Brush cleaning was a very effective cleaning method, and the membrane flux of DMR could be restored. Also, it demonstrated that acid reuse from the phosphate-contained acidic wastewater from wastewater produced in high-phosphate hematite pickling process could be achieved by in-situ self-formed dynamic membrane technology.

Phosphorus removal from domestic sewage by adsorption combined photocatalytic reduction with red mud

Phosphorus removal from domestic sewage by adsorption combined photocatalytic reduction with raw and modified red mud (RM) was studied in this paper. The results indicated that RM dosage, reaction time, stirring rate, phosphorus concentration, and initial pH of solution (pH(i)) were the main factors to effect on phosphorus removal. It was found that the phosphorus removal efficiency of modified red mud (RM-m) under the photocatalytic test conditions was higher than only by adsorption process, while raw red mud (RM-raw) showed no significant difference under the two conditions. With initial phosphorus concentration 8.26mg/L, reaction time 60min, stirring rate 200r/min, under the adsorption and photocatalytic test conditions, the optimum dosage and pH(i) of both RM-raw and RM-m were 1.8g/L and 4.0, respectively, and the corresponding phosphorus removal of RM-raw and RM-m were 90.18 and 91.70%, respectively. The optimum amount of RM-m under the two conditions were 1.6 and 1.5g/L, respectively, the optimal pH(i) 3.0, correspondingly, the phosphorus removal could reach high up to 94.30 and 99.96%, respectively.

Preparation and Application of Mg(OH)2-Based Desulfurization Emulsion from Alkaline Iron Slag

Mg(OH)2-based emulsion has been successfully prepared from the alkaline iron slag in the laboratory for the first time, and the wet Flue Gas Desulfurization (FGD) process with Mg(OH)2-based absorbents was researched through a simulated experimental set-up. The desulfurization efficiency was 89.0%~90.8% under the conditions of sorbent concentration 21.2~63.6 g/L and the retention time (Ts) 30s. Effects of gas flowrate (Q), sorbent concentrate of Mg(OH)2-based emulsion and the retention time (Ts) on the desulfurization efficiency were also investigated in this paper. Research results indicated that Mg(OH)2-based emulsion is a new absorbents for wet FGD technology with investment-saving, low operation cost and high desulfurization efficiency.