Study On The Source Of Imported Lead-containing Raw Materials And Heavy Metal Exposure Risk In Smelting Process

Imported lead-containing raw materials are an important raw material guarantee to support the development of my country's recycled non-ferrous metal industry.Due to the complex sources of lead-containing raw materials and the difficulty of identification,imported lead-containing raw materials are easily mixed with solid waste.These lead-containing raw materials will increase the discharge of heavy metals during the smelting process,causing damage to the ecological environment and human health.At present,my country's related traceability system is still incomplete,and basic research is weak,which cannot effectively support the adjustment of the imported waste catalog and the formulation of related environmental management standards.Therefore,speeding up the research on the traceability of lead-containing raw materials is particularly important,providing data support for my country to scientifically identify the environmental impact of imported lead-containing raw materials and implement precise crackdowns on the entry of foreign waste.This paper selects typical imported lead-containing raw materials from a customs port in Nanning to clarify the source of imported lead-containing raw materials and their physical and chemical characteristics.on this basis,laboratory simulations are used to study the characteristics of heavy metal emissions in the flue gas during the smelting process of lead-containing raw materials and the effect of smelting waste residues.The production characteristics of leaching toxicity.The main results obtained are as follows:(1)Based on lead sulfide concentrate,pyrometallurgical Lead Slag,lead-containing fumes,lead anode slime,lead-rich slag,lead paste,lead oxide,lead-containing wet leaching residue,nine kinds of lead materials such as lead sinter returns the appearance of the characteristics,main elements and phase composition of the fingerprint characteristics,established a good uncertainty,practical and feasible lead raw material source database.(2)When the smelting temperature rises from 500? to 1100?,the concentration of Cu,Zn,Sb,Pb,As and other heavy metals in the smelting flue gas of four raw materials including lead sulfide concentrate,pyrometallurgical lead slag,lead-containing fumes,and lead anode slime are equal Shows an increasing trend.Among them,the amount of heavy metals produced in the smelting flue gas of the lead anode slime raw material is more than that of the other three raw materials.When the content of SiO₂ flux increases from 0 to 20%,the heavy metals in the flue gas show a decreasing trend.The leaching concentrations of Cu,Zn,Sb,Pb and As in the four lead-containing raw material smelting residues all decrease with the increase of smelting temperature.,and the leaching concentration of heavy metals in the slag after low-temperature smelting is higher than that of high-temperature smelting.(3)Using the human health risk assessment model proposed by the U.S.Environmental Protection Agency,the lead anode slime raw materials are carcinogenic at the melting temperature of 500?1100?under the three exposure routes of breathing inhalation,accidental oral ingestion,and skin contact exposure.The risk index TCRI values are 2.16E-06,1.86E-06,2.11E-06,1.89E-06,1.59E-06,the total carcinogenic risk index CRI is greater than 10^-6,and As is the main carcinogenic risk factor,Indicating that there is a certain carcinogenic risk in the utilization and disposal of lead anode slime raw materials,while there is no carcinogenic risk in the utilization and disposal of lead sulfide concentrate,pyrometallurgical lead slag,and lead-containing fumes.The total non-carcinogenic risk index THI of the four lead-containing raw materials in the utilization and disposal process is less than 1,It shows that the non-carcinogenic health risks of the four raw materials in the process of utilization and disposal belong to the acceptable risk level,and the total non-carcinogenic risk is greater in high-temperature smelting than in low-temperature smelting.(4)Integrating the characteristics of heavy metal emissions in the smelting flue gas and leaching process and the results of the health risk assessment,in the actual production process,the doping of lead-containing fumes and lead anode slime in the raw materials should be reduced,and 10%-20%of SiO₂ flux should be appropriately added and control the smelting temperature below 1000?,they can effectively reduce the production and release of heavy metals from the source.