砷、锑、铜、氟等对锡的碘量法和钨的硫氰酸盐比色法均有干扰,当分析上述元素含量较高的矿样时,需要预先分离。为此进行加硫酸铵焙烧除砷的试验,並用含磷酸钠或EDTA而适当提高碱度的浸出液浸出以减少铁、钙、镁对锡、钨的吸附和有利于锡转化为锡酸钠于溶液中。试样经焙烧后砷、锑、氟等被驱除,再碱熔水浸则使铁、钙、镁、钛、锰、锆、钡、银、金、铋、镉、钴、汞、镍、钍、铌、钽和稀土元素,以及绝大部份铜进入沉淀,只有铝、锌、钼、铬 Arsenic, antimony, copper, fluorine and other iodine amount of tin iodine and tungsten thiocyanate colorimetric interference, when the analysis of the above-mentioned elemental mineral samples, the need for pre-separation. To this end with ammonium sulfate roasting arsenic test, and with sodium phosphate or EDTA and appropriate leaching of alkaline leaching leaching to reduce iron, calcium and magnesium on the tin, tungsten adsorption and tin is conducive to the conversion of tin in solution in. After the sample is roasted, the arsenic, antimony and fluorine are expelled, while the re-alkali water immersion makes iron, calcium, magnesium, titanium, manganese, zirconium, barium, silver, gold, bismuth, cadmium, cobalt, mercury, , Niobium, tantalum and rare earth elements, and most of the copper into the precipitate, only aluminum, zinc, molybdenum, chromium