Application Research Of The Wet Reclamation Sludge From Used Clay Sand

Foundry industry produces tens of millions of tons of used clay sand each year inchina. Used clay sand is water-soluble sand, which can get good effect using wetreclamation.The removal rate of adhesive film and water soluble material from sandsurface is high and the reclamation sand can get close to the new sand quality. Wetreclamation of used clay sand will produce large amounts of sewage, and the sewage-treatment process will produce a lot of sludge (accounting for about10%~15%of the totalamount of used sand).A lot of sludge disposal without any stacking and jettison will notonly occupy much farmland with producing secondary pollution but also result in thewaste of resources.This paper attempts to use used clay sand and Wet reclamation sludgeof foundry used clay sand applied to brick making industry, in order to achieve wastereuse.This paper studied that the addition of casting used clay sand and Wet reclamation ofsludge had an effect on properties of fired clay brick and sintered shale brick whichincluded burning loss, bulk density, compressive strength, flexural strength, waterabsorption, freeze-thaw performance, efflorescence, Lime burst and so on. This paper alsoanalysised its causes.We could obtain the best process of sludge fired clay brick andsintered shale brick using orthogonal test. This paper studied and discussed the mechanismforming strength of fired clay brick and sintered shale brick.The result of study indicated that increased the burning loss, water absorption andfreezing and thawing mass loss rate increased by increasing the addition of wetreclamation sludge.The compressive strength of the brick body and flexural strengthincreased and then decreased by the increase of the amount of sludge.When the additionamount of sludge was50%, the compressive strength reached27.18MPa, meeting thenational standard "fired common brick"(GB5101-2003) in MU25level requirement, andthe brick had very good bearing performance.The properties of sintered shale brickdecreased with the increase of the amount of sludge.When the content was60%, thecompressive strength could reach the requirement of MU10.When the addition was70%,sintered shale bricks belonged to unqualified bricks. The best process of sintered clay brick was with the addition of50%, the sintering temperature of1100℃, holding time of6h,and sintered shale brick，s best process was with the addition of30%, the sinteringtemperature of1100℃, holding time of6h.In order to realize the maximum utilization ofthe sludge, when the sludge addition amount of clay bricks was less than70%,and theamount of sludge in sintered shale brick belowed50%, the properties of sintered slugebricks meted the GB5101-2003requirements，sintered sluge bricks could be applied toproduction.By making bricks with wet regeneration sludge of used clay sand,the sludge wasconverted into resources.The waste from the entire producing process would not do harmto environment．The process achieved wet regeneration sludge of used clay sand saflyeffective treatment,and would not have second pollution.According to the analysis ofbenefit, the disposal wet reclamation sludge of used clay sand had specific economicbenefits and environmental benefits using this technology.This study had specificinnovation in the process,the technology was practical and feasible，the design wasreasonable，the operation was simple and convenient，and making sense to the actualproduction．...