Research On The Separation Of Zircon Sand (Power) From Shells Of Investment Casting

Investment casting process has many advantages, excellent surface finish, highdimensional accuracy, applicable to complex shapes, suitable for a variety of alloys,flexible production volume. Therefore, investment casting process is more and morewidely used. With the rapid development of investment casting industry, investmentcasting enterprises in China will produce millions of tons of shells of investment castingeach year. If not processed properly, shells of investment casting will be stockpiled, bringabout occupation of land and pollution the environment. Shells of investment casting is apotential resource as it containing a large amount of zircon sand (powder), and the annualproduction of zircon sand is too low in China to meet domestic demand, therefore, theseparation and utilization of zircon sand（power）from shells of investment casting is agood way to process shells, by which we can alleviate domestic demand, reduce the wasteof land resources and protect the environment at the same time.This paper studied the process route of separation zircon sand (powder) from shellsof investment casting through the beneficiation process. The results show us a goodprocess of separation zircon sand (powder) from shells of investment casting, remove thedebris in shells of investment casting by manual sorting and magnetic separation, thencrush and screen shells of investment casting, mill the thick part of the materiel throughrod mill, screen the materiel again, remove some of the iron-based material in the sand bymagnetic separation, and process the sand though gravity separation and flotation, if theflotation concentrate contents too much iron-based material, soak it in acid to decrease theiron content of flotation concentrate, then rinse the flotation concentrate by water and dryit, and we get zircon sand. The separated zircon sand can meet the second-grade standard. Zircon power can not be separated from mixture by gravity separation and flotation for itsparticle size is too small.The best way to grind is grinding by rod mill, the grinding should last10minutes andthe grinding density should be60%. During gravity separation, the water flow rate forfeeding should be11L/min, the water flow rate for washing should be15.5L/min, and thelateral inclination of bed surface should be3°. During flotation, sodium dodecyl benzenesulfonate is used as collector, octanol is used as regulator, inhibitor is not needed, the bestpH should be5.5, the stirring time should be4minutes, and the particle size of sandshoule be between80to325mesh.