论文部分内容阅读
为了消除汞对环境的污染,根据生产和教学的要求,我们对赤铁矿中全铁的经典K_2Cr_2O_7容量法的测定进行了研究。拟定用铝粉还原Fe~(3+)为Fe~(2+),控制酸度为3N左右,以K_2Cr_2O_7标准溶液滴定至终点,保留了K_2Cr_2O_7法的优点,消除了汞害,用于小批试样分析所得结果与汞盐法相同,若用于大批试样分析,时间过长,还原后的亚铁溶液易被空气氧化,测得结果偏低。以往有人采用通入二氧化碳或通入氮气等方法保护亚铁溶液免受空气氧化,但都过于麻烦。我们采用温度低于16℃的办法,以防止亚铁溶液被空气氧化,还原后的亚铁溶液可稳定3小时。对大批试样同
In order to eliminate the pollution of mercury to the environment, according to the requirements of production and teaching, we studied the determination of the classical K_2Cr_2O_7 volumetric method for total iron in hematite. It is proposed to reduce Fe 3+ with Fe 2 + and control the acidity to about 3N with aluminum powder, titrate K 2 Cr 2 O 7 standard solution to the end point, retain the advantages of K 2 Cr 2 O 7 method, eliminate the mercury damage, The result of sample analysis is the same as that of mercury salt method. If it is used for a large number of sample analysis and the time is too long, the reduced ferrous solution is easily oxidized by air and the result is low. In the past, some people used the method of introducing carbon dioxide or nitrogen gas to protect the ferrous solution from air oxidation, but they were all too troublesome. We use the temperature below 16 ℃ approach to prevent the ferrous solution was air oxidation, reduction of ferrous solution can be stable for 3 hours. The same batch of samples