Exploitation And Application Researches On Novel High-efficiency Flotation Flocculant And Equipment

Flotation equipment and flocculation are cores of flotation. Studying novel complex flocculant of polymer ferric aluminum silicate sulfate (PFASSi) and CAP high-efficient flotation equipment has very important to solve practical problem of wastewater treatment.Using waste-acid of TiO2-indurstry and fly ash(FA) as materials, and, PFASSi is prepared with a novel technology. The best Al-acid stripping rate is 39.26% when mass ratio of NaCl/FA is 0.05:1, solid-liquid ratio is 1:10 under 90 for 1.5 h. The best Si-alkaline stripping rate is 35.88% when alkaline concentration is 5mol/L, solid-liquid proportion is 1:10 under 90癈 for 2h. Polymer ferric aluminum sulfate (PFASS) flocculant has been obtained by means of one-step oxidation-polymerize reaction under 40 and normal pressure for 2h,using NaNO2 as catalyst, air as oxidation, and KI as aid catalyst. After then, red-brown liquid flocculant of PFASSi has been made by means of complex-polymerize.Compared with PAC and PFS, PFASSi has obvious superiority with less-dosage, floe quicker-sediment, lower-cost, wider-pH, and higher-efficient of removing algae, oil, CODcr, SS, color and turbidity in treating algae water of Dian Chi, coking- plant wastewater and three kinds of paper-recovery industry wastewater. The studying results of the species distribution and coagulation-flocculation of PFASSi show that there are different special complex flocculation of PFASSi for treating different wastewater. the optimal technical indexes of PFASSi product are as follows: B=l.5-2.0, npe+Ai/nsi or nFe/nAi=10:l, pH=2.0-4.0 and valid concentration is about 0.2-0.4mol/L.In this paper, the design theory of CAP equipment is preliminarily established. A miniature CAP flotation equipment is designed and made. The wastewater, which is algae water of Dian Chi, coking- plant wastewater and two kinds of paper-recovery industry wastewater, are treated by the CAP equipment respectively. The flotation experimental results show that the reagent consumption is low, the flotation time is short and the purification efficiency is high. The removing efficiency of algae and oil are 99% and 99.8% respectively, the purifying efficiency of SS and turbidity are above 96%and 92% separately; the COD purification efficiency of coking-plant wastewater is 56.5%. Especially, wastewater treatment from algae water of Dian Chi and wastewater of paper-recovery industry is reused or recycled. If single flocculant of the inorganic flocculant is adopted, it has been indicated from the flotation experiment the order of their purification efficiency is: PFASSi> PFS> PAC. If complex reagent with PAM and PFASSi or PFS or PAC is adopted, , the efficiency is higher and the consumption is lower, compared with single reagent.The floe growth, irregularity and formation have been studied for treating aforesaid four kinds of sewage by using PFASSi or complex with PFASSi and PAM. Fractal dimension of their floe are 1.53-1.63 or 1.55-1.73 . It has been explained and concluded from the fractal theory study of coagulation-flocculation and flotation that the mechanism of coagulation-flocculation and the adherence of floes and bubbles is strong adsorption, bridging and network capturing. DLA fractal model of floegrowth is established, which is Vn = kn + p. Ideal fractal model of floe in flotationis also established by means of theoretical deduction, whichis fractal dimension).The more increasingly the floes and bubbles are adhered, the better the flotation efficiency and Df are. Flotation purification efficiency becomes better and floes carrying bubble becomes more compact, when using inorganic polymer flocculant (IFF) and organic polymer flocculant (OFF) as flocculant under long time intense agitating in CAP flotation machine.