抄録
The authors have studies in the first report on the pressometric and gravimetric methods for the determination of carbon dioxide in coals and concluded that the modified pressometric method (ISO/TC 27-490) was suitable for the specification in JIS.
It is necessary to specify a scope and tolerances when a method is accepted in JIS. The authors, therefore, have studied for this purpose, and concluded as follows:
1) The carbon dioxide evolved when low rank coals which belong to class III (Subbituminous) and IV (Lignitic) in ASTM D 388 “Classification of coals by rank” are treated with hydrochloric acid does not usually originate from carbonate minerals. These low rank coals, therefore, should be omitted from the scope of the JIS.
2) Tolerances calculated from the results of interlaboratory experiment are shown in the next table with that of other standards. The precisions of this method are consi-dered as fairly good figure in comparison with that of other standards.
The draft JIS M 8813-1972 has been prepared based on the above studies, and it will be published in the end of 1972.
