在测定钼铁中钼的各种方法中,钼酸铅重量法的准确度虽高,但是所需要的时間很长,所消耗的劳动力又多,因此不能滿足工业分析的需要。而高錳酸鉀容量法,在还原Mo~(6+)时需隔绝空气,为此,手续也麻烦。至于钼的EDTA容量法,均是在MoO_4~=中加入一定量之Ca~(++)或Pb~(++),使其生成CaMoO_4或PbMoO_4沉淀,再滴定滤液中过剩之Ca~(++)或Pb~(++)的间接法。由于要从沉淀中得出清亮溶液,需过滤或經离心机,也不方便。最近,Lassener望月平一等用强碱分离共存的Fe、Cu、Mn等,将Mo~(6+)还原至Mo~(5+)后,用EDTA Among various methods for the determination of molybdenum and molybdenum in molybdenum and iron, the lead molybdate gravimetric method has high accuracy, but takes a long time, consumes a lot of labor, and therefore can not meet the needs of industrial analysis. The potassium permanganate capacity method, the reduction of Mo ~ (6 +) to be isolated from the air, for which procedures are also troublesome. As for the molybdenum EDTA capacity method, a certain amount of Ca ~ (++) or Pb ~ (++) is added into MoO_4 ~ = to make CaMoO_4 or PbMoO_4 precipitate, then the excess Ca_ (+ +) Or Pb ~ (++) indirect method. Due to the precipitation from the clear solution, to be filtered or centrifuged, it is not convenient. Recently, Lassener Mochizuki first class separation of coexisting Fe, Cu, Mn and so on with a strong base, the Mo ~ (6 +) reduced to Mo ~ (5 +), with EDTA