Resumo

MAILA, MD; MAREE, JP  e  CELE, LM. Acid mine water neutralisation with ammonium hydroxide and desalination with barium hydroxide. Water SA [online]. 2014, vol.40, n.3, pp.521-528. ISSN 1816-7950.  http://dx.doi.org/10.4314/wsa.v40i3.16.

In South Africa, acid mine drainage is polluting increasingly scarce ground- and surface water. The ammonium-barium (NB) process described in this paper consists of neutralisation and metal removal with NH₄OH, sulphate removal with Ba(OH)₂ and Ca removal with CO₂. Laboratory studies showed that metals are removed to low levels. This includes Fe(II), the predominant metal in mine water. It is first oxidised to Fe(III), whereafter it precipitates as Fe(OH)₃. Sulphate is removed to low concentrations as BaSO₄. During CO₂ dosing, CaCO₃ is precipitated to its saturation level. The simulation predictions followed the same pattern as the experimental results obtained. This study showed that NH₄OH can be used for treatment of acid mine drainage rich in sulphates and NH₄OH can be recycled in the process. Hydrated lime treatment resulted in removal of the remaining ammonia using a rotary evaporator.

Palavras-chave : acid mine water; ammonium hydroxide; barium hydroxide; sulphate removal.

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