The Study On Preparation Of Anti-radiation Aggregate Used By Electroplating Sludge Riched In Ni And Fe

Sludge with rich heavy metals is potentially harmful solid waste in electroplating industry,which can be divided into containing zinc chrome,nickel iron,copper and other types of sludge according to the heavy metal sludge containing heavy metal elements in the electroplating sludge.This kind of sludge exist heavy metal leaching toxicity and it whould bring environmental pollution.Disposal techniques of electroplating sludge include reclamation and stacking,biological method,heavy metal recycling,ferrite method etc.Using the excellent ray shielding property of heavy metal,the electroplating sludge can be fired to radiation aggregate,and it can be used as building materials.This way is a kind of harmless and effective wayfor recycling electroplating sludge.This paper based on the national natural science fund project?51272192?,carrying out the research of aggregate with nickel,iron electroplating sludge fired radiation protection function.Main results are as follows:1.Studying the influence law of sludge content of radiation protection aggregate on roasting temperature,mineral composition and performance is studied with sludge riched in heavy metals Ni and Fe and shale as raw materials.When the sludge content is 10%⁹0%,with the increase of sludge content,roasting temperature of aggregate falls down,firing range becomes narrow,the compressive strength and resistance to radiation shielding performance of aggregate increases at first and then decreases.The appropriate mix content of the sludge range is 40%⁶0%,roasting temperature is1075?¹125?;The main mineral of aggregate is quartz?SiO₂?,kyanite?Al₂SiO₅?,magnetite?Fe₃O₄?,nickel iron ore spinel?NiFe₂O₄?.2.Studying the rule of the sintering system influencing on radiation protection performance and mechanical performance of anti-radiation aggregate with rich Ni,Fe plating sludge,and discussesing burning mechanism of use of electroplating sludge with rich heavy metals Fe,Ni to be artificial aggregate.With the rising of roasting temperature,high-temperature liquid phase of aggregate increases,liquid viscosity decreases,gas reaction in the process of gas expansion resistance decreases,the aggregate are more likely to swell and the compressive strength and weak linear coefficient of aggregate increases first and then decreases;With the increase of heating rate,volatilization of gas componentshe aggregate raw ball producing liquid is incomplete,the gas components of aggregate and volatile components is more in the high temperature roasting,which is easy to cause more connected hole and closed hole,shielding performance and mechanical performance decreases;With the extension of roasting temperature and time,the glass phase increases,the apparent density and mechanical properties increase first then decrease,and the gamma-ray shielding performance improved first then reduced,the suitable calcination temperature is 1075?¹125?,calcination time is 25³5 min;With increase of cooling rate,the surface liquid of aggregate will rapidly vitrify,so as to save the expansion effect in high temperature,so the strength is reduced and shielding performance decreases.3.Identifying production process parameters of electroplating sludge containing Ni manufactured to be aggregate with anti-radiation function.Using electroplating sludge containing Ni,Fe as main raw materials and as raw materials with shale,following n=3.6⁵.7 of raw material and 2.75².80 of silica alumina ratio,during burning system of 300⁵00?preheating about 30 min,then at 5?/min heating rate rose to 1075¹125?calcine about 20⁴0 min,can crank out anti-radiation function aggregate with 25.2 Mpa compressive strength,apparent density in 2.4³.0×10³kg·cm^-3,less than 1.43%of saturated bibulous rate beyond 24h and 0.25cm^-11 of linear weakening coefficient coping with 0.662MeV?-rays.4.According to the HJT299-2007?Solid waste sulfuric acid nitric acid leaching toxicity method?,carrying out the experiment of heavy metal leaching about anti-radiation function aggregate when pH is respectively 3.2,7 and 12.6.Leaching concentration of heavy metal ions of aggregate is the highest in the acidic condition.Ni leaching concentration with 0.602 mg/L,according with national standard GB5085.3-2007?Hazardous waste identification standard?.The solidification of heavy metal ions is above 99.99%.