硼溶液蒸发过程中硼的挥发及硼同位素分馏

Boron Volatilization and its Isotope Fractionation during Evaporation of Boron Solution

用蒸发实验研究了浓度为10-6级的硼在水和稀HCl溶液蒸发时的挥发度、同位素分馏和甘露醇的影响。结果表明，在溶液中有等摩尔的甘露醇和Cs都存在的条件下，硼才能在蒸发时和蒸干后保持定量回收；硼在不加入甘露醇或Cs的稀HCl溶液中蒸发时也能定量回收，但是不能蒸干；若要蒸干．必须加入等摩尔的甘露醇，才能保持硼的定量回收。蒸发液和残留液的同位素测定表明，11B仇先从近中性和酸性溶液的蒸发中贫化。此结果对于硼需要预富集的过程是非常重要的。

Evaporation experiments were undertaken to determine the volatility of levels of ppm concentration of boron in water and dilute HCl in the presence and absence of equimolar mannitol and/or cesium. Multiple 10ml aliquots prepared identically were evaporated to various extents or just to dryness and heated 10 to 20 minutes after reaching dryness under filtered air at 60℃.Boron was only retained quantitatively in Water during evaporation and after reaching dryness in the presence of both equimolar mannitol and cesium. Boron was retained quantitatively in dilute HCl solution during evaporation, without mannitol or cesium. But it could be retained when the dilute HCl just reached dryness and thereafter only in the presence of equimolar mannitol.Isotopic measurements of the evaporation solutions and residues indicate that the heavier isotope, 11B,is preferentially lost from the near neutral and acidic solutions examined. The results are pertinent for procedures requiring preconcentration of boron.