Determination of Total Molybdenum, Molybdic Oxide and Molybdenum Sulfide in Molybdenum Ore by Polarography

Molybdenite is the major mineral in molybdenum ore. The phase analysis of molybdenum ore is required to determine sulfide minerals and oxide minerals. The phase analyses of molybdenum ores such as molybdenite, molybdite, powellite and molybdate galena were taken by photometry and Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES). In this paper, the molybdenum ore sample was dissolved with aqua regia-sulfuric acid. The total molybdenum was extracted by alkali solution and the majority of the other elements were separated by precipitation. Molybdic oxides were leached by sodium carbonate and ammonium hydroxide solution. Molybdenum sulfides were obtained to dissolve residue. The contents of total molybdenum, molybdic oxide and molybdenum sulfide were determined by rapid polarography in a sulfuric acid-potassium chlorate-diphenyl glycollic acid system. The linear range of the method was 0.04-0.4 mg/L, and the detection limit was 0.028 mg/L. Three molybdenum ore samples were carried on phase analysis and the results were consistent with those obtained by photometry. The sum contents of molybdic oxide and molybdenum sulfide conformed to the total molybdenum content. RSDs (n=8) were 1.69%-3.56% for total molybdenum, molybdic oxide and molybdenum sulfide. This method was fast and suitable for practical batch samples.