Study On The Heavy Metal Transport Characteristics Of Multicomponent Domestic Waste In The Incineration Process

The waste incineration technology receive increasing attention today with the increasing quantity of domestic waste, because it can reduce the volume of waste and recycle the energy effectively. This article takes eight components of waste as the research object, it is respectively : wood, paper, textile, rubber, recycled PE, recycled PP, recycled PS and recycled PVC. To study the change of weight loss and the transfer characteristics of heavy metals( Pb, Cu, Zn, Ni, Cd, Cr) under single sample and co-firing conditions, experiments were conducted on a tube furnace and a TAS-990 atomic absorption spectrophotometer. The research range of temperature was 500~1000°C.The results show that the PVC has the largest quantity of Pb among the eight waste components, so as the Zn in rubber and the Cr in textile. According to the mass remaining rate of eight components in 1000°C, we can classify the eight waste components into three types :(1) the components have low mass remaining rate(<5%) : PE, textile;(2) the components have middle mass remaining rate(5%~20%) : wood, paper, rubber, PP, PS;(3) the components have high mass remaining rate(>20%) : PVC. The rough sorting of six heavy metals base on the volatilization degree is : Cr>Ni>Cu≈Zn>Pb>Cd, from easy to difficult.The mixed combustion of two components have effect on the weight loss :(1) the mixed combustion of biomass and plastics waste can basically increase the mass of residue in bottom ash, especially the paper has a larger effect than the wood;(2) when the textile co-fire respectively with PE, PP and PS, the mass of residue in bottom ash will increase, the mixed combustion of textile and PVC can reduce the mass of residue in bottom ash, the mixed combustion of textile and rubber has no significant effect on the weight loss;(3) the mixed combustion of wood and paper, wood and textile, paper and textile can increase the mass of residue in bottom ash, but the effect of wood and textile, paper and textile is limited;(4) the mixed combustion of rubber and plastics waste can increase the mass of residue in bottom ash, but the mass of residue in bottom ash can be reduced when the rubber co-fire with PVC above 900°C;(5) when the PVC co-fire respectively with PE, PP and PS in low temperature, the mass of residue in bottom ash will increase, but the results are opposite in high temperature;(6) the pairings between PE, PP and PS have no significant effect on the weight loss under co-firing condition.The pairings among eight components have different effect on the transport of six heavy metal under co-firing condition.(1) The Pb can be captured in bottom ash through this combinations : wood and rubber(≤600°C), paper and rubber, paper and PP, paper and PS, textile and rubber(≤700°C), textile and PP(≤600°C), PE and PP;(2) The Cu can be captured in bottom ash through this combinations : rubber and wood, rubber and paper, wood and paper, wood and textile, PVC and wood, PVC and paper(≤800°C), PVC and textile, PVC and rubber(≤700°C), PVC and PE, PVC and PS, PE and PS(≥900°C);(3) The Zn can be captured in bottom ash through this combinations : wood and plastics(except rubber), wood and paper, wood and textile, PVC and PE(≥800°C);(4) The Ni can be captured in bottom ash through this combinations : wood and rubber, wood and PE, PVC and wood(≤800°C), PVC and paper(≤800°C), PVC and textile(≤800°C);(5) The Cd can be captured in bottom ash through this combinations : paper and rubber(≤800°C), textile and PP(≤600°C), textile and PVC(≤700°C), rubber and PVC(≤600°C);(6) The Cr can be captured in bottom ash through this combinations : paper and PE, paper and PS. According to the view of reduce the potential ecological risk in bottom ash, these combinations should be separated : wood and rubber, wood and PE, wood and PVC, paper and rubber, wood and paper, rubber and PE.The systematic research on the heavy metal transport characteristics under co-firing condition can provide the data support and the theoretical basis for the domestic waste sorting collection and the heavy metal control in the incineration process.