Study On Flocculant And Corrosion And Scale Inhibitor Used In Blast Furnace Gas Wash Water Cooling Circulation System

Steel mills enterprises is the industrial major water users and wastewater emitters,blast furnace gas wash water is a kind of industrial wastewater that contains a lot ofinorganic suspended solids in it.A large amount of blast furnace gas wash water isproduced by steel mills enterprises every day and certainly would be a serious pollutionand waste of water resources if not be treated properly. So the blast furnace gas washwater to be treated and reuse has the significance of water conservation and reduceenvironmental pollution.Blast furnace gas washing wastewater treatment and reuse aregenerally removed by coagulation and sedimentation wastewater SS, COD and otherimpurities into the cooling system reuse. Two important factors to affect its operatingefficiency and cost are flocculant coagulation and sedimentation effects and corrosion andscaling problems in cooling system.For these two aspects, this paper based on the actualsituation of An Yang steel mills Plant Blast Furnace Gas washing wastewater treatment,study efficient flocculant and efficient corrosion and scale inhibitors, and taking intoaccount of its environmentally friendship.First, we developed an efficient compound flocculant for blast furnace gas washwater: PFS: PAM=2:1.The best dosage of this recipe is16mg/L, the optimum pH is8,thetreatment effect is very stable for it has a good adaptability to the pH fluctuations normalfor blast furnace gas wash water (7to9) and temperature fluctuations (40℃to70℃), SS,COD removal rate can reach95%.This recipe has better treatment effect and lower coststhan the flocculant used in An Yang steel mills (PAC: PAM=4:1dosage of50mg/L),better sludge dewatering performance and solve the problem of PAC affecting the effect ofscale and corrosion inhibitor such as Phosphorus-based corrosion and scale inhibitor andzinc.Secondly, we developed an efficient and environmental friendly compound corrosionand scale inhibitor for blast furnace gas wash cycle cooling water system: PASP=40%,PESP=40%, the sodium molybdate=8.3%, zinc chloride=5%,sodium gluconate=6.7%.The best dosage of this recipe is30mg/L, the optimum pH is7~8, the treatmenteffect is more stable, and weakly affected by pH and temperature changes, can adapted to fluctuations in the pH and temperature of the cooling water circulation.The corrosioninhibition rate and scaling inhibition rate of this recipe can up to92.14%and94.17%.The compound flocculant and complex corrosion and scale inhibitor developed inthis paper showed excellent treatment effect in beaker experiment,and more effective thanflocculant and corrosion and scale inhibitor used in An Yang steel mills.And the treatmenteffect of the two formulations are stable for showing good adaptability for pH,temperature changes. However, further pilot experiment is necessary,to simulate the actualsituation of the blast furnace gas wash water cooling circulation system and test theperformance of the two recipe, then can really put them into use.