Preparation Of Polysilicate Aluminium Ferric Coagulant With Fly Ash And Its Use In Oilfield Reinjection Water Treatment

The coagulation effect is affected by coagulant's performance directly. It is important to study and development new type coagulant of high effect,low toxicity and cost.According to the research and development of polymeric silicic acid complex coagulants, aiming at the character of oilfield reinjection water, at several calcining temperature and time, in different pH value,different acid leaching time and different content compound ratio of ferrum,silicon and aluminum, using resourceful fly ash,oil of vitriol and alkali obtained series polysilicate aluminium ferric (PSAF). Moreover, we did some experiment and analysed the result, summarized the best process parameter to making PSAF according the experiment data.Having researched preparation technique and process of macromolecule coagulant PSAF, analyzed its makeup and character, preparation for new efficient reliable coagulant which is suitable for oilfield reinjection water, and made it carried out in actual application processing.Through composing the PSAF with ferrum, silicon and aluminum at different molar ratio, applied the chemical analysis, analytical techniques of modern equipment, interaced the reciprocity between silicon and ferrum in PSAF to study the mechanism of flocculation. Studies have shown that coagulant PSAF is not a simple mixture of raw materials, but the complex formed by copolymer morphology. In the conditions of Al / Fe mass ratio of 1.0, Si / (Al + Fe) ratio of 0.5, the activation temperature of fly ash 900℃to 1000℃, acid leaching temperature is 70℃to 80℃, acid leaching reaction time is 2h, mass fraction of 30% hydrochloric acid, preparation for the composite flocculant PSAF with fly ash to remove suspended particles from wastewater by 87.9 percent.Congulant PSAF have two function: charge neutralization and adsorption bridging flocculation. Congulant PSAF of homemade used in the experiment were treated wastewater and oil return, and compared and analyzed the widely used water treatment pharmacy PFS with PAC. Meanwhile, systematic analysed the the main factors of congulant PSAF treatment effect to determine the optimal experimental conditions of this water treatment conditions and process parameters. The results show that, with the PSAF capacity of 75 mg L1, COD removal rate of 87 percent, oil removal ratio of 95% or more, the flocculation impact of PSAF is better than PFS and PAC.