GB 6730.3-86 铁矿石化学分析方法重量法测定分析试样中吸湿水量 ISO 2596 Iron ores - Determination of hygroscopic moisture in analytical samples - Gravimetric, Karl Fischer and mass-loss methods ISO 7335 Iron ores - Determination of combined water content - Karl Fischer titrimetric method JIS M8211 铁矿石-化合水定量方法