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钛量法直接滴定铁的方法准确性不逊于重铬酸钾法,且可消除铬汞的公害.铬是致癌物,因此钛量法优于重铬酸钾法.钛量法实际应用不多的原因是钛(Ⅲ)标准液不易储存。保护方法不方便,滴定度是一个变数. 我们测得钛(Ⅲ)溶液敞开于空气中,其被氧化速度每小时达0.3～0.5%。用氢气、二氧化碳保护法,或用液体石腊复盖表面,或用甘油和石油醚保护,其被氧化速度也还有每小时0.1%左右。将钛(Ⅲ)溶液配在70%的磷酸中,虽能稳定一周时间,但是具有粘性,不宜作为标准溶液使用.加入乙酸和硫酸铵于钛(Ⅲ)溶液中,使其氧化还原电势提高0.2～0.3伏特,以降低其被氧化速度。经测试,钛(Ⅲ)被氧
The titrimetric method of titrimetric titration of iron is not inferior to that of potassium dichromate method, and it can eliminate the pollution of chromium and mercury.Chromium is a carcinogen, so the amount of titanium is superior to potassium dichromate. The reason is titanium (Ⅲ) standard solution is not easy to store. The protection method is inconvenient, and the titer is a variable.We measured the titanium (III) solution in the air and its oxidation rate was 0.3-0.5% per hour. Hydrogen, carbon dioxide protection, or liquid paraffin covered surface, or with glycerol and petroleum ether protection, the oxidation rate is also about 0.1% per hour. Titanium (Ⅲ) solution with 70% phosphoric acid, although stable for a week, but with a sticky, not as a standard solution .According to the addition of acetic acid and ammonium sulfate in titanium (Ⅲ) solution, its redox potential increased by 0.2 ~ 0.3 volts to reduce the rate of oxidation. After testing, titanium (Ⅲ) is oxygen