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土壤矿质全量的测定,在常规分析方法中大都采用碱熔法分解土样,重量法测定硅,脱硅后的滤液测定其他组分.优点是熔快速,分解完全,测硅的方法较准确;存在的问题是由于熔融分解均在较高的温度下进行,往往带入较大量的坩埚材料以及大量的碱金属盐类,影响以后某些组份的测定,钠、钾必须另外单独取样进行,使分析过程复杂化.例如用坩埚熔样时,熔融过程中可能生成金属铁,与铂形成合金,既影响测定,又侵蚀坩埚,合金化了的坩埚如清洗不净,铁还可能沾污别的样品.微量铂也会使络合滴定中某些常用的指示剂封闭.更主要的是由于铂坩埚价格昂贵而又不易购置,使该法适用的广泛性受到限制.用苛性碱在镍、银坩埚中熔融,给以后的分析引进大量银、镍,也使某些组份的分析产生困难.在
Soil mineral content determination, in most of the conventional analysis methods using alkali melting decomposition of soil samples, gravimetric method for determination of silicon, desilication of the filtrate after determination of other components. Advantages of rapid melting, decomposition completely, the method of measuring silicon more accurate; The problem is due to the melting and decomposition are carried out at higher temperatures, often into a larger amount of crucible material and a large number of alkali salts affect the determination of some of the later components, sodium and potassium must be an additional separate sampling, Such as crucible melting sample, the melting process may generate metal iron, forming an alloy with platinum, both affect the determination, and erosion of the crucible, alloy crucible, such as cleaning is not clean, iron may also be contaminated Of trace platinum will also complex complex titration of some of the commonly used indicator closed.More major is due to platinum crucible expensive but not easy to purchase, so that the law applicable to a wide range of restrictions with caustic in nickel, Silver crucible melting, to the subsequent analysis of the introduction of a large number of silver, nickel, but also make some of the components of the analysis difficult.