Home / Standards / GB/T 20973-2007 GB/T 20973-2007 Abolished Bentonite 膨润土 Standard Type GBT ICS 73.080 CCS Q69 Status 废止 Issue Date 2007-06-22 Implementation 2008-01-01 Responsible Dept 中国建筑材料联合会 Drafting Unit N/A