PRECISION FILTER MEDIUM FOR MOLTEN METAL

摘要

PROBLEM TO BE SOLVED: To remove even fine solid impurities included in molten aluminum by filtration by using a precision filter medium obtd. by firing a mixture of aggregate particles having a specified average particle diameter and an inorg. binder. SOLUTION: A mixture of aggregate particles such as ceramic aggregate having 300-1,500μm average particle diameter and an inorg. binder having <15wt.% B2 O3 , content and preferably comprising 60-92 wt.% crystal. powder having a spinel crystal structure, 5 to <15 wt.% B2 O3 , 0-10 wt.% SiO2 , and the balance Al2 O3 and MgO is fired to produce the objective precision filter medium. The majority of the inorg. binder is allowed to exist at the crosslinked parts between the aggregate particles and the remainder is allowed to exist in <=60μm layer thickness on the surfaces of the aggregate particles.