Abstract: A new technique is proposed for multi-purpose utilization of Tibetan szaibelyite by metathetical reaction with ammonium sulfate to prepare boric acid and magnesium carbonate.Effects of technique conditions,such as reaction temperature,reaction time,initial concentration of ammonium sulfate,and proportion of ammonium sulfate to its stoichiometry,on the leaching rate of boron were investigated.The optimum process conditions were as follows,reaction temperature was 100 ℃,reaction time was at 2.0~2.5 h,initial concentration of ammonium sulfate was at 9%~11 % (mass fraction),and the proportion of ammonium sulfate to its stoichiometry was 110% .The yields of boric acid and magnesium carbonate could reach over 95% and 90%,respectively.The technique is favorable to making full use of the boron and magnesium in Tibe-tan szaibelyite and increasing the yield of boron.

Key words: szaibelyite, boric acid, magnesium carbonate