盐卤硼酸盐化学——Ⅷ.盐卤中硼酸盐的存在形式和表示方式

CHEMISTRY OF BORATE IN SALT LAKE BRINE VIII. THE FORM OF BORATE EXISTING IN CONCENTRATED BRINE AND ITS EXPRESSION

在含硼盐卤蒸发过程中无固体硼酸盐析出的情况下,用芒硝回溶晒水方式制得高含硼浓缩卤水。采用盐酸滴定该浓缩盐卤的pH,对卤水的盐酸-pH滴定曲线进行定性解释的基础上进行定量计算,结果认为浓缩盐卤中硼酸盐是以四硼酸镁的“综合统计”形式存在,即浓缩卤水中除了存在四硼酸镁外,可能还同时存在n2的MgO·nB_2O_s,其存在量必需符合n=2这一表观结果。同时还对不同浓缩盐卤进行粒子配对成盐处理,结果表明盐卤中硼酸盐可以表示为MgO·2B_2O_3。

The concentrated brine containing abundant borate and formed during spontaneous evaporation and the form of borate existing in concentrated brine were studied by hydrochloric acid-pH titration. The quantitative calculation of titration after the qualitative explanation of pH titration curve was made. It comes to the conclusion that the borate existing in the brine is in comprehensive statistic form of tetraborate B4O7(OH)42-.During spontaneous evaporation of brine the mirabilite is dissolved in general, the borate does not precipitate as solid phase. The composition of each concentrated brine is measured and the calculation of salt-formation is made by species paired equation. Based on the calculation results mentioned above, it may be considered that the form of borate existing in salt lake brine can be expressed as a comprehensive statistical form of tetraborats, such as MgO·2B2O3.