超高合金よりタングステン及びタンタルの回収

In the process of the manufacture of Ultra Hard．Steel with the Powder Metallurgy Method，it is unavoidable to produuce the reluctant and abundant scraps，from which the expensive metals are not easily recovered． The author recovered tungsten and tantalum as oxides at the average rate of 97％ （tungsten oxide）and 9O％ （tantalum oxide）from the scrap pieces which consisted of tungesten carbide（8％），titanium carbide（6％），tantalum carbide（4％）and cobalt（l0％). The most important chemical treatments are to be experienced．in the next processes，the pieces are heated 800℃ for l.5−2 hours in the air，then they become powders of oxides not to be attainable with physical methods. Potassium hydroxide，five times as much，is added to the weighed sample，then fused−at 800℃ for about one time，and allowed to cool in the air. Next tme，potassium carbonate, five times as much，is added to the cooled one， and then fused atll00℃ thorougly．On this o㏄asion，the iron crucible is less corroded．For the chemical separation of tungsten and tantalum，the greatest nervous attention is necessary so as not to fail to catch either of them completely.