Study on Separation and Extraction of Boric Acid from Saline Lake Brine
Received:March 13, 2017  Revised:March 16, 2017
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DOI:doi:10.3969/j.issn.1007-7545.2017.08.008
KeyWord:boric acid; acidification; carbonation; saline lake brine
              
AuthorInstitution
chenkang 中南大学
XU Hui 中南大学
WANG Zhe 中南大学
WANG Chao 中南大学
YANG Xi-yun 中南大学
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Abstract:
      With brines from salt lake as raw materials, boric acid was separated and extracted by a combined process of acidification, magnesium precipitation with ammonia, and carbonation. Yield of boron is 72%, purity of crude boric acid product is 72% after drying, and purity of boric acid is 99.52% after recrystallization, which meet the first grade of national standard GB/T 538-2006, under the optimum conditions including acid addition of 0.7%, reaction temperature of 60 ℃, and freezing time of 5.5 h. Leaching rate of boron is 95.52% under the optimum carbonation conditions including excess coefficient of ammonium bicarbonate of 1.4, reaction temperature of 50 ℃, ratio of solid to liquid of 10 g/L, and reaction time of 2 h. With the advantages of simple operation and low cost, this process can separate and purify most of magnesium in brine to obtain high-purity magnesium oxide.
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