Study On Coking Wastewater Treatment With Industry Coke Powder

A large amount of coking wastewater is produced in the coking, coal gas purification and product recovery process by the domestic iron and steel enterprises. The coking wastewater is a kind of complex organic effluent with high concentration and high toxicity. The COD and chroma of coking wastewater couldn't reach the nation discharge standard with twice biochemical treatment. Aimed at the problems, the issue raised an way of adsorption treatment of the coking wastewater with the extinguishing coke powder instead of active carbon. The specific study is as follows:(1) Laboratory still experiment: the effect of added coke powder's quantity, coke powder's grain diameter, coke wastewater's pH and adsorption time to treatment effect of the coke wastewater was studied . The results showed that 100g/l of added coke powder's quantity, 50-60 mesh of coke powder's grain diameter, pH of the coke wastewater:2.0-3.0 and 3-4h adsorption time were suitable.(2) Small-scale continuous dynamic experiment: it detected the change of outflow's pH, chroma and COD with three pretreatments of coking wastewater. The results showed that: with pretreatment of 10%wt sulfuric acid and 0.25‰PFAS, the adsorbed effect of coke powder was almost the same and they are better than the way without any pretreatment.(3) Enlargement experiment: with rough and fine coke powder as adsorbents, effect of the former is better than the later. Chroma removals continuously added as the time goes by and COD is decreased before coke powder reaching saturation, and increased after that.(4) Sintering experiment: its results show the adsorption process does not have adverse effects to the process of sintering which means that reusing the coke powder and wastewater can be achieved at the same time.(5) Kinetics experiment:It is showed by study that the pseudo second orderkinetic model is the best, it is much more suitable for the process; the adsorptionequilibrium showed that the process is an exothermic reaction and the Langmuir equation could properly describe the adsorbed process.The whole results manifest that dealing with the coking wastewater with coke powder has a good effect. It reaches the aims of reusing of and internal recycling and reusing of coke powder at the same time and has a promising prospect of industrial application.