| 摘要 |
The invention relates to a method and apparatus of removing sulphate, calcium and/or other soluble metals from waste water wherein NaOH and AI(OH)3 are contacted at a temperature of at least 60°C and the molar ratio NaOH:AI(OH)3 at least 1.0, for preparing sodium aluminate, the waste water is contacted with the obtained sodium aluminate and a first calcium compound for producing a sludge containing ettringite, a solid-liquid separation is performed for the sludge containing ettringite for separating solids from the liquid thereby producing a first solution, the first solution is contacted with a carbonating agent for neutralising the first solution and precipitating calcium contained in the first solution as calcium carbonate, and a solid-liquid separation is performed for separating precipitated calcium carbonate from the first solution in order to obtain water having a reduced sulphate, calcium and/or other soluble metals content. |
