铝,硅含量＞50%的耐火砖及类似品(指超过50%的三氧化二铝,二氧化硅等耐火陶瓷建材制品)

Refractory bricks and similar articles containing by weight more than 50% of alumina(Al2O3), of silica(SiO2)or of a mixture or compound of these products