Experimental Study On Preparation Of Coated Sand By The Quartzose Sandstone From Huangdan,Muchuan County,Sichuan

Siliceous raw materials are very important industrial minerals raw materials which are widely distributed in nature.Its have been widely used in traditional industrial and modern technology areas.Foundry coated sand is a casting material which is used for producing castings with more complex and sophisticated structure.Compared with the ordinary foundry quartz sand,it has a higher added value of products,meanwhile,more specific requirements on the quality of coated sand has been putted forward.Muchuan Huangdan quartz sandstone has a very huge storage.All aspects of conditions such as mine exploitation and product transportation are favorable.Picking up the speed of its mining and utilization has a very important significance to promote the development of local economy,drive the development of the surrounding foundry industry and compensate for the lack of coated sand in Sichuan.This thesis defense in Huangdan quartz sandstone as the research object,mainly from the characteristics of quartzose sandstone from Huangdan,Muchuan county and its application of foundry molding sand,process conditions study on preparation of ordinary coated sand,high temperature resistance coated sand and easy collapsibility coated sand by the quartzose sandstone from Huangdan for test.Using lab center XRF-1800 X-ray fluorescence spectrometer,rigaku 5530 scanning electron microscope,DX-2700 X-ray diffraction,LV100 polarizing microscope,PM-6000microscope for chemical composition analysis,mineral composition analysis,particle size and grain shape analysis.According to the characteristics of the mine,using the foundry quartz sand processing by this ore as base sand,aiming at specific quality indicators for coated sand,research the raw sand heating temperature,the mixed time after adding the resin,the temperature of adding curing agent,the mixed time after adding curing agent impact on the performance of prepare coated sand,And to determine the optimal process parameters.Finally,based on the optimizing process,by adding different additives,preparing the qualified high temperature resistance coated sand and easy collapsibility coated sand.The research results obtained in this paper and the experiment progress is as follow:1.Study on characteristics of quartzose sandstone from Huangdan,Muchuan county and its application of foundry molding sand（1）The content of quartzose sandstone from Huangdan,Muchuan SiO₂ and quartz are about 93%⁹6%and 90%respectively,and the content of the clay mineral between quartz grains is about 8%.（2）The natural granularity of quartz in the ore is between 32 to 80 mesh,the content of the granularity of its proceeding quartz sand for glass industry from 40 to140 mesh is over 95%,and the granularity from 40 to 70 mesh is 76.42%.（3）The natural grain shape of quartz grains mainly is round-subangular,and the quartz grains angularity of the ore and its processed product is less than 1.3,the angularity of base sand meet the requirement of foundry quartz sand.（4）The foundry quartz sand products,including 40/70,50/100 and 70/140 which made of the ore meet national and related manufactory quality standards.The indicators of foundry quartz sand processed by the ore also can meet the requirement of foundry coated sand,therefore,it can be used as raw sand of coated sand.2.Experimental study on preparation of ordinary coated sand by the quartzose sandstone from Huangdan,Muchuan county（1）Optimizing process parameters of processing ordinary coated sand by the quartzose sandstone from Huangdan,Muchuan county is:the raw sand heating temperature is 170°C,the mixed time after adding the resin is 80s,the temperature of adding curing agent is 95°C,the mixed time after adding curing agent is 50s.（2）Based on the optimizing process,the ordinary coated sand can be processed by 30/70 mesh,50/100 mesh,70/140 mesh raw sand.The resin amount of 30/70 mesh raw sand should not less than 2.5%.The resin amount of 50/100 mesh raw sand should not less than 2.5%.The resin amount of 70/140 mesh raw sand should not less than 3%.（3）The coated sand products,including 30/70,50/100 and 70/140 which made of the quartzose sandstone from Huangdan,Muchuan county meet the quality requirements of national standard.The properties of 70/140 mesh coated sand are close to the coated sand processed by other factory,it meet manufactory quality standards.3.Experimental study on preparation of high temperature resistance coated sand by the quartzose sandstone from Huangdan,Muchuan county（1）The high temperature resistance performance of high temperature resistance coated sand is better than the ordinary coated sand.（2）Zircon sand and chromite sand both can be used for processing high temperature resistance coated sand.Both of comparison,the effect of zircon sand is better than chromite sand,but its price is expensive,so in actual production,selecting the type and amount of additives should be according to customer demand.4.Experimental study on preparation of easy collapsibility coated sand by the quartzose sandstone from Huangdan,Muchuan county（1）Both KCl and NaCl used as collapsing agent can prepare easy collapsibility coated sand.Both of comparison,NaCl should be selected,and the optimal amount of NaCl is 20%of resin.（2）Both limestone and CaCO₃ used as collapsing agent can prepare easy collapsibility coated sand,the effect of them are basically same,in the actual production process,limestone should be selected,and the optimal amount of limestone is 20%of resin.（3）Both of comparison about NaCl and limestone as collapsing agent,easy collapsibility coated sand prepared by using NaCl as collapsing agent has better collapsibility.The bending strength of easy collapsibility coated sand prepared by using limestone as collapsing agent increases slightly,but the collapsibility of easy collapsibility coated sand prepared by using limestone as collapsing agent is not better.Therefore,in the actual production process,it should be combined with the actual situation to determine to select whether NaCl or limestone as collapsing agent.