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在铁路运输、动力工程、工农业生产和生活用水以及有关科学研究、水文地质普查、地质勘探等方面,天然水化学成分的分析具有极其重要的意义。天然水的主要成分——Ca~(++)、Mg~(++)、SO_4~(--)和Cl~-等系某些研究单位和生产部门经常分析的项目。常法SO_4~(--)以BaSO_4形式的重量法测定,虽原理简单,但由于操作繁琐,且有共沉淀现象,致使精确度甚低。如用BaSO_4形式的比浊法,则需事先估计试样中的SO_4~(--)含量,然后绘制工作曲线,以内插法方能确定其含量。如用钡盐溶液直接或倒转滴定SO_4~(--),虽可用的指示剂甚多,但要取得良好结果并非易事。水样中Cl~-常用银量法测定。但该法灵敏度、准确度均较差。经典的Ca~(++)的草酸盐重量或容量测定法,均难避免沉淀等繁琐手续。如水中存有大量铁、铝,则需
In the fields of railway transportation, power engineering, industrial and agricultural production and domestic water, as well as scientific research, hydrogeological census and geological exploration, the analysis of natural water chemical composition is extremely important. The main components of natural water - Ca ~ (++), Mg ~ (++), SO_4 ~ (-) and Cl ~ - and some other research units and production departments often analyze the project. Common method SO_4 ~ (-) to BaSO_4 form of gravimetric determination, although the principle is simple, but due to complicated operation, and co-precipitation phenomenon, resulting in very low accuracy. Such as the use of BaSO_4 turbidimetric method, you need to estimate the sample in the SO_4 ~ (-) content, and then draw the working curve, interpolation method to determine its content. Such as barium salt solution directly or reverse titration SO_4 ~ (-), although there are many indicators available, but to obtain good results is not easy. Cl ~ in water samples - Determination of silver content. However, the sensitivity of the law, the accuracy is poor. Classic Ca ~ (++) oxalate weight or volume determination, are difficult to avoid the cumbersome procedures such as precipitation. If there is a lot of water in the iron, aluminum, you need