Borax recovery using sodium metaborate and boric acid intermediates

摘要

Sodium metaborate is recovered from a boron-containing first feed solution by extraction of the first feed solution with a 1,3-diol, followed by re-extraction with a solution of an alkali metal hydroxide. Boric acid is recovered from a boron-containing second feed solution by extraction of the second feed solution with a water-insoluble aromatic polyol, followed by re-extraction with mineral acid. The boric acid and sodium metaborate are reacted to form sodium tetraborate. By exchanging sodium ions in the polyol extract with potassium ions, the potassium salts of the mineral acid may be recovered from the polyol as a by-product.