Study On Analysis And Determination Of Resource And Environmental Attributes Of Multi-source Solid Wastes From Copper Smelting Process

Nonferrous metal smelting process produce solid wastes and have the characteristics of multi-source and large quantity.At the same time,they have dual attributes of resource and environment,which are interrelated and interactive.In order to maximize the resource recovery and minimize the environmental risk of the multi-source solid wastes during copper smelting processes,it is of great significance to analyze and define the resource and environmental attributes of solid wastes.13 kinds of samples were collected from a copper smelter in Hunan Province,China.The physical properties of the samples such as moisture content,particle size distribution and surface morphology were systematically measured.The resource characteristics of the samples such as elements content and phase structure were comprehensively analyzed.The environmental characteristics of samples such as leaching concentration and chemical form were studied in detail.And then the resource and environmental attributes of solid wastes were preliminarily analyzed.The long-term stability of solid wastes as well as the release behavior and characteristics of metal elements in solid wastes were deeply investigated.A model was constructed to scientifically distinguish and define the resource and environmental attributes of solid wastes at the first time,while a database was developed.The research has made the following main innovative achievements.The study established a preliminary analytical list of multi-source solid wastes from copper smelting process and proposed scientific suggestions on treatment and disposal.The content of Cu,Pb,Zn and As in the solid wastes of the whole process is high,especially the content of recyclable metals in anode slag,black copper sludge,blowing white dust,arsenic sulfide sludge and lead filter cake.The above solid wastes can be returned to the process of flow or comprehensive recovery.Except for waste refractories and neutralization sludge,the leaching toxicity of other solid wastes was also exceeded the standard degrees.Waste refractories,smelting slag,residue benefication tailings and neutralization sludge are slight risk,anode slag is medium risk,and the potential ecological risk of other solid wastes are serious risk,which indicates that these solid wastes must be properly treated and disposed.Among the solid wastes,As and Cd contribute the most to the potential hazard index,and they are the metal elements which have the most serious influence on the copper smelting system.The simulated stacking and static/semi-dynamic erosion experiments were carried out for 6 months to evaluate the long-term environmental risk and environmental stability of solid wastes in detail.The main risk elements of multi-source solid wastes from copper smelting process are As and Cd.The leaching toxicity of As and Cd increased greatly in the simulated storage test and exceeded seriously in the static/semi-dynamic erosion test.The potential ecological risk index of blowing white dust and arsenic sulfide sludge will further increase during the simulated storage process,which must be strictly controlled.The characteristics and mechanism of release process of various elements in solid wastes were revealed.Complex surface reactions occured in the leaching process,most of which are in accordance with the double constant equation and Elovich equation.The release of metals is mainly achieved by the desorption and dissolution of surface adsorbed substances.Various metals show different release patterns due to differences in content and chemical form.Some metals,such as Cu in anode slag,Ca in desulfurized gypsum sludge and waste acid treated gypsum sludge,continuously released during the leaching process,and their environmental risks will last for the whole stockpiling process.Nevertheless,in the semi-dynamic erosion of raw material dust,smelting dust,blowing white dust and lead filter cake,metals such as As and Cd presented a rapid release stage of surface weakly adsorbed metal ions and a slow release stage of complex and interlayer metal ions which are difficult to release.The environmental risks of these metals are mainly concentrated in the first stage,that it is,the initial stage of storage,to which special attention shall be paid to.Based on analytic hierarchy process,the index system was established,and the determination model of resources and environmental attributes of multi-source solid wastes from copper smelting process was constructed.The attribute discrimination method was invented to realize the accurate discrimination and determination of the attributes of solid wastes.According to the discrimination and determination results of solid waste samples,some suggestions on management and treatment were put forward.Based on the research results and the determination model,with the help of My SQL database and ORM framework,the analytical database of resource and environmental attributes of multi-source solid wastes from copper smelting process was developed.Data query,data analysis and data analysis modules are implemented,which provide data support for the management,treatment and disposal of multi-source solid waste in copper smelting system.