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铬酸钡容量法测定钡是经典方法,由于该法行之有效,仍在日常生产分析中使用。但对铁矿石中钡的测定,因存在大量铁,于pH5.7～6.1沉淀铬酸钡时发生水解,使测定结果偏高。曾有人用柠檬酸掩蔽铁以消除干扰。经试验表明,由于柠檬酸的缓冲作用,溶液的沉淀酸度不易调节,掩蔽铁的效果也不理想。本文采用氨三乙酸(NTA)掩蔽铁(Ⅲ)效果较好,1克NTA可掩蔽100毫克铁(Ⅲ),並可借助铁-氨三乙酸络合物,在不同pH下显不同颜色,来指示和调节溶液的沉淀酸度。方法简便,可用于铁矿石中含量在0.x～xx%钡的测定。分析步骤称取0.1000～0.5000克试样于刚玉坩
Barium chromate volumetric method for the determination of barium is a classic method, as the method is effective, is still used in daily production analysis. However, the determination of barium in iron ore, due to the presence of a large amount of iron, hydrolyzed barium titanate at a pH of 5.7 to 6.1, resulting in a high measurement. Some people used citric acid masking iron to eliminate interference. The test shows that, due to the buffering effect of citric acid, the solution is not easy to adjust the acidity of precipitation, masking the effect of iron is not ideal. In this paper, the use of NTA masked iron (III) is better, 1 g NTA can mask 100 mg of iron (III), and with iron - ammonia triacetic acid complex, at different pH significant different colors to Indicate and adjust the solution’s acidity. The method is simple and convenient and can be used for the determination of barium in the range of 0.x to xx% in iron ore. Analysis step Weigh 0.1000 ~ 0.5000 grams of sample in corundum crucible