Based on the characteristics of Niobium with xylenol orange-red complex formation, the use of spectrophotometric techniques; sample was dissolved in aqua regia, perchloric acid or sulfuric smoke, niobium and fluorine add hydrofluoric acid to form a stable complex (H7NbF7) in 0.18N hydrochloric acid media generates xylenol orange-red complex, whereby the colorimetric determination of fluoride overdose beryllium sulfate or aluminum sulfate eliminated. Zirconium is available masking with CYDTA.

Use acid heat treatment of low-grade bauxite, iron after hydrochloric acid leaching, plus DESILICATION ammonium fluoride, hydrofluoric acid under ultrasound desilication and concentrated sulfuric acid titanium fine chemical control and other steps the production of high-purity aluminum fluoride, the optimum conditions: control of concentrated hydrochloric acid liquid to solid ratio of 1: 1, acid leaching at 60%, acid leaching time was 30min; control the amount of ammonium fluoride was added to the reaction ratio of 1.4 times, calcination temperature of 500 ℃, roasting time 2h; hydrofluoric acid was added to control liquid to solid ratio of 3: 1, strengthen the temperature is 60 ℃, time strengthen lh; controlled addition of concentrated sulfuric acid liquid to solid ratio of 3: 1, refinement temperature is 90 ℃, refinement time was 40min. Under these conditions, the yield of aluminum more than 90% purity of the aluminum fluoride products reached 97.2%, to meet the standards related chemical products.

Detection methods for the establishment of the Korean anthracite imports of mercury content, to evaluate the distribution and environmental risks moved by microwave digestion - accurately quantify its atomic fluorescence spectrometry (MD-AFS), using robust statistical techniques to describe the overall content features.