The Methods Of Polycrystalline Silicon Wastewater Solid-liquid Separation And Recycling The Chloride Research

Because of the process of polysilicon production characteristics, its industrial waste water from the water volume, suspended solids content, high chlorine ion content, as our country’s increasing strict sewage discharge standard, in addition to the traditional membrane filter machine processing craft processing cost on the high side, so it is confronted with some technical challenges, it is imperative to reduce processing costs.This article through the combination of the laboratory test and engineering field test research and introduce a new method of treating polysilicon wastewater treatment. Through a mixture of medicine addition reaction system, multilevel precipitation system, sludge dewatering system pressure filtration and recycling system processing unit, to deal with polycrystalline silicon wastewater. The research of the system with medicine way and recycling conditions to guide practical engineering, get the following conclusion:This experiment through the study of the PAC, FeSO4FeCl3, Al2(SO4)3four chemical flocculant to contain the Polycrystalline silicon wastewater, determined the coagulants and coagulant type, dosing quantity and dosing conditions. Experiments show that PAC coagulation effect is best, precipitation rate is the highest. To determine the best flocculation conditions for:Dosing ratio0.12g/L wastewater, concentration for1200mg/L, pH=8, stirring speed for240r/min, stirring time of2min. Sure coagulant PAM dosing ratio0.01g/L wastewater, dosing optimal concentration of1g/L, best stirring speed for120r/min, stirring time10s. Through the experiment of sure PAM optimization anionic#3PAM is the best type, not only the effect is big body, but also fastest settlement, the largest amount precipitation, clear liquid on the most clear, the dosage is also at least. Through the field experiment, confirmed the sludge concentration tank sludge concentration degree and the corresponding relation of dosage, draw dosing pump range and concentrated settlement ratio relation graph, guide practical engineering application.CaCl2coagulation effect of impact experiments show that the content of how much the CaCl2coagulation effect had no affect on the basic of the circulation of the subsequent CaO process basic. Using the chloride method CaO cycle, waste water treatment of polysilicon cycle, in circulation processing, up to five times when cycles, the circulating water content of calcium chloride to63g/100mL water, basic reached the maximum number of recycling The cooling water chloride after anion exchange resin bed after processing, chloride ion content can be reduced to300mg/L, every10g resin can deal with cooling water around140mL. After saturated Anion exchange resin need regeneration, every10g resin need20mL10g/L NaOH solution regeneration. Regeneration of wastewater containing mainly produces a certain amount of alkali, and can completely as configuration of lime-milk water.