灼烧重量法测定炼钢铁水预处理用钙基脱硫剂中氢氧化钙  

Determination of calcium hydroxide in calcium-based desulfurizer for hot metal pretreatment in steelmaking by burning gravimetric method

作　　者：朱春要 陆娜萍 赵希文 董登超 ZHU Chunyao;LU Naping;ZHAO Xiwen;DONG Dengchao(Analysis&Characterization Center,Institute of Research of Iron&Steel,Jiangsu Province/Sha-Steel,Zhangjiagang 215625,China)

机构地区：[1]江苏省沙钢钢铁研究院分析测试中心,江苏张家港215625

出　　处：《冶金分析》2021年第6期44-50,共7页Metallurgical Analysis

摘　　要：炼钢铁水预处理用钙基脱硫剂中的游离氧化钙极易吸湿转化为氢氧化钙,氢氧化钙在预脱硫加料过程中会产生剧烈分解反应,造成铁水飞溅及铁水温度降低,不利于脱硫成本的控制。因此,准确测定脱硫剂中氢氧化钙含量对脱硫工艺具有重要意义。将放置1个月前后的炼钢铁水预处理用钙基脱硫剂进行X射线衍射分析,结果表明,游离氧化钙质量分数不小于55%的情况下,脱硫剂中不存在自由水及结合水,仅存在以氢氧化钙形式存在的化合水。试验利用氢氧化钙在高温条件下易分解为氧化钙和水的特点,通过灼烧重量法测得分解前后水损失的质量差,经过换算间接得到氢氧化钙的含量,实现了炼钢铁水预处理用钙基脱硫剂中氢氧化钙含量的测定。研究表明:试样粒度不大于125μm,称样量为1.00 g时,测得结果的相对标准偏差最小。灼烧温度试验表明:采用铂金坩埚作为灼烧容器,减量法快速称量试样,在580℃条件下灼烧1.0~1.5 h,氢氧化钙即可分解完全,且脱硫剂中碳酸钙等组分不对测定产生影响。采用实验方法对炼钢铁水预处理用钙基脱硫剂实际样品进行分析,结果的相对标准偏差(n=6)为1.1%~2.0%;采用热重分析进行方法对照,结果与实验方法基本一致,方法回收率在96%~104%之间。The free calcium oxide in the calcium-based desulfurizer for hot metal pretreatment in steelmaking was easily converted into calcium hydroxide because of the high hydroscopic property.In the process of pre-desulfurization and feeding,calcium hydroxide would undergo a violent decomposition reaction,resulting in spattering of hot metal and reduction of hot metal temperature,which was not conducive to the control of desulfurization cost.Therefore,the accurate determination of calcium hydroxide in desulfurizer had great significance for desulfurization process.The calcium-based desulfurizer sample for hot metal pretreatment in steelmaking that was placed before and after one month was analyzed by X-ray diffraction.The results showed that,when the content of free calcium oxide was not less than 55%,there was no free water and bound water in desulfurizer,and the water existed only in the form of constitution water of calcium hydroxide.Calcium hydroxide was easily decomposed into calcium oxide and water under high temperature.Taking advantage of this characteristic,the content of calcium hydroxide could be indirectly obtained with conversion from the mass difference of water loss before and after decomposition,which was determined by burning gravimetric method.Thus,the determination of calcium hydroxide content in calcium-based desulfurizer for hot metal pretreatment in steelmaking was realized.The results indicated that,The relative standard deviation(RSD)was least with the particle size not larger than 125μm and the sample mass of 1.00 g.In burning temperature test,the platinum crucible was used as the burning container and the sample was rapidly weighed by subtraction method.It was found that the calcium hydroxide could be decomposed completely after burning at 580℃ for 1.0-1.5 h.Moreover,calcium carbonate and other components in the desulfurizer had no influence on the determination.The proposed method was applied to analyze the calcium-based desulfurizer samples for hot metal pretreatment in steelmaking.The rela

关 键 词：钙基脱硫剂 灼烧重量法 热分析仪 氢氧化钙 

分 类 号：O655.1[理学—分析化学]