Study On State Of Organic Compounds In Sodium Aluminate Liquors

Essential organic compounds are identified in Bayer liquors by GC-MS. Quantitation of organic acids in Bayer liquors by ion chromatography and reverse phase high performance liquid chromatography, respectively.Details are as following:(1) To establish the method for identification of organic compounds in Bayer liquors by GC-MS.Separating organic compounds in Bayer liquors on HP-5 chromatography column by procedure heating using Agilent 6890 GC combineing in Agilent 5973 MS, and qualitiing the organic compounds by searching MS database. The results show that primary organic compounds in Bayer liquors are organic acids, it is confirmed including oxalic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, benzoic acid, succinic acid, glutaric acid, o-phthalic acid, and also including long-carbochain organic acids, for instance, tetradecoic acid, palmic acid, stearic acid. In addition, the species and content of organic compounds have great difference in Bayer liquors in different producing areas.(2) The research provided the method for simultaneous determination of organic acids and inorganic anions in Bayer liquors by IC.The samples are pretreated by cation exchange resin column and OnGuard H column respectively. The experiment adopts US Dionex Co. ICS-2500 IC apparatus by gradient ion chromatography with suppressed conductivity detection. The flow rate is 1.20ml/min, sample size is 25μL, and column temperature is 30°C. By calculating concentration results from the peak area data, in 33 min, Formate, acetate, propionate, oxalate, succinate, glutarate, o-phthalate, fluoride, chloride and sulfate were separated and determined on an IonPac AS11-HC column with KOH as the eluent. (3) Quantitation of organic acids in Bayer liquors by RP-HPLC for the first time.The mobile phase consisted of monopotassium phosphate-phosphoric acid-methanol-water. In 10 min, the separation and determination of organic acids were achieved on Kromasil C-18 chromatography column by isocratic elution, the detection wavelength is 215nm, flow rate is 1.3ml/min, column temperature is 22°C, and sample size is 20μL. In five different Bayer liquors, oxalic acid, tartaric acid, acetic acid, succinic acid, butene diacid and glutaric acid were quantification by standard curve method, respectively.