Study On Solidification Of Heavy Metalpollution In Solid Waste Of Zhubugangindustrial Zone

With the continuous progress of urbanization in China,the amount of new construction,reconstruction,expansion and demolition is increasing rapidly,resulting in a large number of construction waste.Traditional landfill take up large amounts of land and may cause environmental problems.The construction waste as recycled building materials for the production of raw materials,not only can reduce the environmental load,but also can reduce the production cost.However,if the construction waste contains excessive heavy metal,such as industrial waste in chemical factory and construction rubbish,it cannot be directly used to make recycled materials.If the construction waste is made into building components,when subjected to leaching of rain or surface water and groundwater,the harmful substances such as heavy metals leaching will cause environmental pollution to the surrounding environment.The Zhubugang Industrial Zone of Xiangtan has been discontinued and overall relocated,but the area left much heavy metal solid waste.In order to properly handle the heavy metal pollution of solid waste in the industrial zone,this paper is based on the construction waste of the Zhubugang Industrial Zone,we carry out the experimental research on species,content and distribution of heavy metals,configure suitable curing test raw materials,use cement solidification technology,makes cement solid solution and test curing effect of heavy metals.The main work and research results are as follows:1.After crushing the solid waste sample of industrial zone,through studying the species,content and distribution of heavy metals,we found that the solid waste is not hazardous waste which have leaching toxicity.It is difficult to use the solid waste as the curing test material because the leaching property is different between the waste.From the heavy metal detection report of industrial zone,it can be found that the heavy metal pollution in industrial areas mainly are cadmium,lead and nickel,so we consider adding corresponding heavy metal drug into collected waste,and then analyzed the heavy metal leaching toxicity.2.In order to obtain the appropriate curing experiment material,we add heavy metal drug in solid waste to study its leaching property.We found that the heavy metal leaching concentration decreased greatly after mixed with solid waste,the effective concentration is difficult to measure when the drug addition is low.When the amount of nickel added exceeds 2%,the leaching concentration increases greatly,the leaching concentration of lead is affected by acid leaching agent and filtration.We finally add six hydrated nickel chloride or cadmium nitrate as 10% composition of mixed solid waste.The mixed solid waste is used as raw material for curing test,of which nickel leaching concentration is about 128mg/L and cadmium leaching concentration is about 2.09mg/L.3.Using 5 kinds of solid waste cement ratios("1: 1","1: 1.3"," 1: 2","1: 4","1: 8")to analysis curing effect,we found that the solid waste cement ratios of "1: 1" or the curing ratio of “4: 4: 0: 2”(cement consumption: solid waste consumption: sand consumption: water consumption),is the more appropriate curing ratio.In the case of P.O42.5,the curing effect of the rate “4: 4: 0: 2” on Cd is 3.95 times that of the rate “0.5:4:3.5:2”,and the curing effect of the rate “4: 4: 0: 2” on Ni is 3.01 times that of the rate “0.5:4:3.5:2”.4.Using 5 kinds of cements(P.O42.5,P.C32.5R,P.F,P.P,P.S)to analyze the curing effect,we found that P.O42.5 has better curing effect than other cement.When the ratio of “4: 4: 0: 2” was choosed,the curing effect of P.O42.5 on Cd was 2.22 times that of P.P,and the curing effect of P.O42.5 on Ni was 2.37 times that of P.P.5.Considering the best choice of curing solution according to the curing effect,we can choose P.O42.5 and the ratio "4: 4: 0: 2".At this time,the leaching rate of Ni was only 0.17% of the leaching rate before curing,and the leaching rate of Cd was only 1.1% of the leaching rate before curing,which was the lowest in each group.It can be used as a reference for the treatment of heavy metal pollution in Zhubugang.