Identification And Harmless Disposal Of The Hazardous Properties Of Titanium Dioxide Acid Sludge

Titanium dioxide is the most excellent white pigment.And its production process mainly includes sulphuric acid and chloride.Relatively speaking,chlorination process is of higher quality,better economic benefits and more energy saving and environmental protection.The developed countries have mainly adopted or recommend the chloride method of titanium production.The capacity of Titanium dioxide in our country is No.2 in the world.But since the core technology of the chloride method of titanium production has not been mastered,99%of Titanium dioxide is produced by sulfuric acid method.The waste acid and the acid sludge,is produced a lot by the production process of sulfuric acid process of production of titanium dioxide.is in National hazardous waste list’HW34 waste acid’.Its Dangerous characteristic is C(corrosion)and T(toxicity).The corrosion of acid sludge chiefly stems from the using of the concentrated sulfuric acid in the process of acidolysis.The toxicity of acid sludge chiefly stems from the associated minerals of titanium ores,the impurities of the concentrated sulfuric and the flocculant which is added to the process of acidolysis.According to the Identification Standard for Hazardous Wastes,the dangerous characteristic of the acid sludge of one titanium dioxide factory in Sichuan Province is analyzed for this research.The analysis shows that this acid sludge is the hazardous waste only with corrosivity,because it does not have the leaching toxicity or the acute toxicity.And the toxic substances content is below the specified value of the Identification Standard for Hazardous Wastes.In this study,the acid sludge adopts harmless treatment by water.By experiments in the laboratory and the field test,the results show that the corrosivity can be removed by the waste water treatment technology.After thoroughly washing,the content of the corrosivity,the leaching toxicity and the toxicant of the acid sludge below the specified value of the Identification Standard for Hazardous Wastes.The Wastewater,generated by washing,can reached the discharging standard by the Waste Water Treatment of the titanium dioxide factory.And it will not have the secondary pollution.This research can provide a theoretical basis of the harmless disposal and pollution control of the sulfuric acid solution of titanium dioxide.