Optimization Of Cold Rolling Mill Sludge Separation Process And Pilot Designation

Cold rolling is the main production process of rolled strip steel.Magnetic filters on a cold rolling line produce a lot of cold rolling mill sludge.Because of its great harm to the environment and inflammability,it is now listed in the National Catalogue of Hazardous Wastes(NCHWs).The waste rolling oil and metal powder in the cold rolling mill sludge are closely combined and very viscous.Therefore,the lack of effective means of treatment is a major problem in the environmental protection production of iron and steel enterprises.Based on current situation,thesis carried out the optimization and pilot design of the non-destructive separation and reuse of cold rolling mill sludge.The purpose is to provide basic data and technical support for practical applications.The thesis first studies the apparent kinetics of solid-liquid extraction for the extraction process and explores the diffusion control model of the extraction process.The influence of magnetic filtration products on the external diffusion between 1,2-dichloroethane was eliminated by adjusting the rotational speed.The results of laboratory intermittent experiments show,when the stirring speed is 300 r/min and the solvent-to-oil ratio is 5:1,the extraction process of Cold rolling mill sludge is affected by the internal diffusion model.When the extraction temperature is 55℃,the extraction kinetic equation is expressed as 1-2/3α-(1α)2/3=0.0027t.apparent activation energy is 30.51 kJ/mol。Secondly,the process conditions of extraction and separation were optimized by response surface analysis and verified by experiments.The results show that the influencing factors of extraction are,in order,the ratio of agent to oil,temperature,and extraction time.Aiming at the 75%rolling oil recovery rate,under the optimized conditions:the ratio of agent to oil 5:1,extraction temperature 67.0℃,extraction time 28.0 min,the average cold rolling oil recovery was 74.52%.The packed distillation column can efficiently separate the extraction liquid,and the purity of 1,2-dichloroethane can reach 99.9%or more,and the content of 1,2-dichloroethane in the recovered rolling oil is less than 0.1%.A distillation model was established in Aspen Plus and the simulation results were consistent with the experimental results.The feed tray and reflux ratio were optimized by Aspen Plus.Under optimum conditions,the purity of recovered 1,2-dichloroethane and recovered rolling oil can be higher than 99.50%respectivelyThe main indexes of the composition,saponification value,acid value and viscosity of the recovered cold-rolled rolling oil are basically the same as those of the newly added rolling oil,and meet the requirements of the reuse index.About 39%of the rolling oil remained in the recovered iron powder can be removed with a cleaning agent.The content of iron in recovered iron powder is more than 80%,and the content of impurity metal is very small.The particle size of iron powder is in the micron level,and the potential additional value is high.Finally,according to the 8t/month processing capacity,the thesis also carried out the pilot process design of cold rolling magnetic filtration product separation process.The PFD drawing and PID drawing are designed and drawn,and the equipment arrangement drawing is completed in the 68m3 container,which is safe and convenient.The results of this thesis provide a way for the resource utilization of cold rolling mill sludge,which has economic value and significant social benefits.