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鋁合金中镁的絡合滴定方法,多数系用氫氧化鈉溶解试样,不溶解残留物主要为錳、鉻、钛、鎂、铁、銅、鎳及少量鋁、硅。残留物用酸溶解后用氨水——溴水、氨水——草酸銨、銅試剂氧化鋅分离錳、铁、鋁、钛等。这些方法多数没有考虑鈣的影响(鋁合金中有时含0.04%鈣)。而草酸銨分离对于少量鈣也不能沉淀,这样往往使结果偏高,当鎂含量低时(<0.3%),这些誤差也值得考虑的。用盐酸溶解試样,不經分离滴定鎂,由于只能取小量試样(0.1克),因此只适用于鎂含量高的試样。
Aluminum alloy magnesium complexation titration method, the majority of sodium hydroxide to dissolve the sample, insoluble residues are mainly manganese, chromium, titanium, magnesium, iron, copper, nickel and a small amount of aluminum, silicon. After the residue is dissolved in acid, manganese, iron, aluminum, titanium and the like are separated with ammonia-bromine water, ammonia-ammonium oxalate and copper reagent zinc oxide. Most of these methods do not consider the effect of calcium (aluminum alloys sometimes contain 0.04% calcium). Ammonium oxalate separation, however, can not precipitate small amounts of calcium, which tends to result in higher results. These errors are also worth considering when the magnesium content is low (<0.3%). Dissolved with hydrochloric acid samples, titration without separation of magnesium, as only a small sample (0.1 g), and therefore only applies to high magnesium content of the sample.