graded coal meaning in Chinese
分级的煤
过筛煤
筛过煤
Examples
- Solid fuels . international codification system for medium and superior grade coals
固体燃料.中档煤和高档煤的国际编码系统 - Effect of coal size and different size grade coal petrographtic feature on coking coal property
煤的粒度特征及不同粒级煤的煤岩特征对炼焦煤性质的影响