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土壤和土壤膠体的全量分析,一般多采用 Na_2CO_2熔融法。但此法手续甚繁,特别是脱矽过程尤为费时。C.A.华西里耶夫曾用动物膠脱矽,但仍未能予以满意的改进。左藤三郎应用 HF—H_2SO_4消化土壤样品,用减重法计算 SiO_2的含量。这样简化了操作手续,提高了工作效率;但其本身却存在有难以克服的缺点,因碱金属和碱土金属的硫酸盐只有在1000℃以上才能变为氧化物,特别是硫酸钙,需要在1400℃左右始能变为CaO,而要完成这样高温的灼烧是有困难的,因而,当土样中 Ca、Mg、K 和 Na 总量超过1%时,SiO_2的测定,将产生较大的误差。
The total amount of soil and soil colloids analysis, the general use of Na_2CO_2 melting method. However, this method is very complicated procedures, especially the process of desiliconization is particularly time-consuming. C.A. Wassiliyev used animal glue off silicon, but still failed to be satisfactorily improved. Zuo Saburo used HF-H_2SO_4 to digest soil samples, and the weight loss method was used to calculate the content of SiO_2. This simplifies the operation procedure and increases the working efficiency; however, it has its own insurmountable shortcoming because alkali and alkaline earth metal sulfates can become oxides only above 1000 ° C., in particular calcium sulfate, ° C or so can become CaO, and to complete such a high temperature burning is difficult, therefore, when the soil samples of Ca, Mg, K and Na total amount of more than 1%, the determination of SiO_2, will have a larger error.