Mold material recycling:Precision casting using resin base model material, due to the high quality requirements for investment casting, mostly with molding material with new material down casting, stainless steel castings.And after demoulding recycling pattern material, after remelting filter used to make water the moudle of riser system.When using wax base model material, the mould material can be recycled after demoulding, used to make new moudle.But when used in the cycle performance will deteriorate, the pattern material brittleness increases, ash content, less liquidity, shrinkage rate increases, the color from white to brown, which mainly related to the mold material deterioration of stearic acid in.Precision casting, therefore, as far as possible in order to restore the original performance of the old model, will be removed from the old mold material soap salt, commonly used method with hydrochloric acid (sulfuric acid) treatment, active white soil treatment method and electrolytic recovery method.