试样用混合熔剂熔融,稀盐酸浸取,定容,移取部分试液,通过控制各元素的酸度,分别用光度法测定SiO2和P；EG-TA滴定法测定CaO,EDTA滴定法测定MgO；强碱沉淀分离氟盐置换、EDTA滴定法测定TAl.另称取1份试样用三氯化铁溶解,加入过量的氢氧化钠,滤液在pH值4.5的乙酸—乙酸铵缓冲介质中,加入过量的EDTA标准溶液,在煮沸条件下与MAl络合后,以PAN为指示剂,用铜标准溶液返滴定过量的EDTA；加氟化物取代,铜标准溶液二次返滴定,计算MAl量,再换算为 Al2O3量.实验确定三氯化铁浓度为8%、用量50 mL 及用振荡器或摇动的最佳时间为60 min.该方法测定 SiO2、CaO、MgO、P、Al2O3及MAl的相对偏差分别小于0.718%、2.819%、1.171%、7.143%、0.178%和1.013%,完全满足快速分析的需要.% The sample melted with mixed flux, leaching with dilute hydrochloric acid, constant volume, removing a part of solution, through the control of the acidity of each element, respectively the SiO2 and P were determined by photometric method; the CaO was determined by EGTA titration method and the MgO was determined by EDTA titration method; the TAl was determined by alkali precipitation separation of fluoride salt replacement and EDTA titration method. The other a sample with ferric chloride dissolving, excess sodium hydroxide was added. The filtrate in acetic acid-ammonium acetate buffer solution at pH 4.5 was added excessive EDTA standard solution and made complexation with the MAl in the boiling condition. Making PAN as indicator, using copper standard solution back titration of excess EDTA, adding fluoride to replace copper standard solution, two times back titration, the mass fraction of the MAl was calculated and the mass fraction of the Al2O3 was converted. The concentration and dosage of the ferric chloride determined by test are 8% and 50 mL and the best shake time or by an oscillator is 60 min. The RSDs of SiO2, CaO, MgO, P, TAl, Al2O3 and MAl respectively are less than 0.718%, 2.819%, 1.171%, 7.143%, 0.178 % and 1.013%, fully satisfying the need of fast analysis.
展开▼
