Study On Comprehensive Utilization Of Pyrite Cinder Which Has Copper With High Arsenic

Pyrite cinder is the waste of the proeess of the acid production which using the pyriterite as the raw materia. At present a large amount of pyrite cinder is stored up or filled in buries proeessing, not only it occupies plenty of land, but also pollution to air, water and earth. The compounds of iron and oxygen are the main compostion in a pyrite cinder, in which the content of iron is generally between 30%-60%. Many useful materials such as Cu in the pyrite cinder, and it is a kind of valuable reused resource, but the sulfuric acid residue commonly contains higher impurity content. Especially, the presence of arsenic in the sulfuric acid residue will result the sulfuric acid residue cannot be recycled as iron concentrate. Arsenic influence the microstructure of the steel and reduce the mechanical properties. Arsenic can also cause a series of technological problems and environmenltal issues as a harmful element. Therefore, removal of the harmful impurities in the sulfuric acid residue and recycling of the iron resources not only eliminates the impact on the environment, but also gets a certain degree of economic benefits.In this paper, in the full reference basis for comprehensive utilization of pyrite cinder and for study on the removal of arsenic containing material, high arsenic pyrite cinder containing copper was studied. In the sulfuric acid residue, Fe content reached 51.15%, As content was 3.35%, Cu content was 1.02%, the main form of iron is hematite (Fe2O3) and magnetite (Fe3O4), the main form of arsenic is arsenic trioxide(As2O3), and the main form of copper is CuFe2O4. The sulfuric acid residue presented in vaious structures, such as disseminated structures, honeycomb structure and loose surface structure. Some gangue and minerals were wrapped parceled and adhered with each other. Impurity elements distribute uniformly on the surface. This complex intergrowth structure caused its separation method of physical or mechanical processing more difficult.Experimental study based on the mineral properties, the process that sulfuric acid residue is leaehed by sulfuric acid solution, which can remove As and Cu elementin pyrite cinder effectively, improve the Fe grade. To obtain optimum process conditions, the paper studied effect of sulfuric acid concentration, solid liquid ratio, temperature, the reaction time, water washing on Fe, As and Cu concent of simple. The optimum technical conditions of removing of As and Cu are:the concentration of arsenic removal reagent is 15%, the temperature is 60 ℃, the solid liquid ratio is 1:3, the reaetion time is 3.0 hours, and washing two times. Experimental results of sulfuric acid leaching in following optimum conditions process showed that:the content of arsenic down to 0.20%, the content of copper reduced to 0.39% and the grade of Fe improved 57.66%, As and Fe content in sample can achieve the quality requirement of raw material of iron ore sintering plant.Due to the leaching solution of containing iron, arsenic and copper, experimental using the method of the neutralization precipitation of arsenic and iron remove arsenic and iron, and the copper remains in solution. In view of the main solution of trivalent arsenic and ferrous iron, pentavalent arsenic toxicity is priceless, and pentavalent arsenic and ferric iron to form iron more easily to form precipitation. So in the neutralization precipitation before using hydrogen peroxide oxidation of trivalent arsenic. Experiment showed that the neutralization precipitation optimum conditions for arsenic removal under normal temperature:the end of pH of precipitate is 3, the reaetion time is 10min. The results show that the maximum arsenic removal rate was 99.89%, the iron removal rate was 99.77%, and the copper loss rate is only 3.35%, the content of copper in solution reached 1.4g/L, it has value of extracting and recycling. The thermodynamics of neutralization and precipitation of iron and arsenic are analysed theoretically, demonstrated the correctness of the final pH value neutralization and precipitation.Through the study on the mechanism of leaching kinetics of arsenic in pyrite cinder, and provide a theoretical basis for the sulfuric acid leaching sulfuric acid residue and remove arsenic, has the important guiding significance for treatment of sulfuric acid from pyrite cinders, and provide a theoretical reference for the harmless treatment of the high arsenic material.