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土壤中全磷全钾的测定,过去大多是分别进行,也有连续进行测定的,方法多采用史密史法和硷熔法,这二法都需使用价值昂贵又不易购买的铂金坩堝。近来有人建议用磁质坩堝熔样,根据我们的实地工作和试验,认为用磁质坩堝熔样,在最初时还可以,若要长期进行分析,则发现坩堝有大量损失。在这样情况下,我们大胆地进行了试验,采用银质坩堝熔样,硷熔法,结果颇为满意,且这种坩堝价值便宜又到处可購到,现将我们试用的方法分述如下,以便和广大同行工作者请教商确。 原理:采用硷式熔融硅酸盐矿石方法。土壤与Na_2CO_3在高温熔融时,所有钾磷均转化为易溶于水的盐类,然后用水提取,使其与硅、铁、铝、钙等分离,然后用亚硝酸钴钠法定钾、钼兰法定磷。
Determination of total phosphorus in the soil, mostly in the past were conducted separately, but also for continuous determination, the method used more Smith’s law and alkaline melting method, both methods need to use expensive and difficult to buy platinum crucible. Recently, it has been proposed to use magnetic crucibles for melting samples. Based on our field work and tests, it is believed that it is possible to initially use a magnetic crucible for melting samples, and for long-term analysis, a large loss of crucibles has been found. In such circumstances, we boldly conducted a trial, the use of silver crucible melting, alkaline melting method, the results are quite satisfactory, and the crucible is cheap and everywhere to buy, now we try out the method are described below, In order to consult with the majority of peer workers indeed. Principle: The use of alkaline fused silicate ore method. When the soil and Na_2CO_3 are melted at high temperature, all potassium and phosphorus are converted into salts that are readily soluble in water, and then extracted with water to separate them from silicon, iron, aluminum and calcium, and then sodium potassium nitrite, potassium, Legal phosphorus.