| 摘要 |
Water purification is effected by a controlled recycling process involving addition to the water of precipitating agents and polymeric flocculants in a so-called 'Ca phosphate-polymer-recycling by solution' (CPRS) process. A CPRS process to purify water is effected by introduction as precipitating agent of phosphoric acid with milk of lime/limewater (Ca(OH)2) or CaCl2 in caustic soda (CaOH) or Na phosphate in HCl with milk of lime/lime water/Ca Cl2 (Ca(OH)2), setting the pH to 6-12 with milk of lime/lime water/Ca Cl2 (Ca(OH)2) and adding an anionic polymer at pH 6-12 to give additional flocculation. There are added as flocculant (i) an acidic 'Polypor' (polymer-phosphorus solution for recycling) solution obtained by dispersing phosphoric acid with an anionic crosslinked polymer and/or (ii) an alkaline 'Polycar' (polymer-Ca(OH)2 solution for recycling) solution obtained by dispersing Ca(OH)2 with an anionic crosslinked polymer. Independent claims are also included for: (1) the recycling apparatus, this consisting of: (a) a stirred chamber with a separator producing a recycle solution of the Ca phosphate sediment with diluted HCl; (b) a still chamber yielding dissolved acid solution of definite conductivity and having a separating wall between (a) and (b), the wall being up to two-thirds of a lattice-work of fineness down to 5 mu ; and (c) a control device measuring the conductivity of the phosphoric acid or Na phosphate in HCl or of the 'Polypor' and ensuring that the conductivity converges with a target value; and (2) a dosing device comprising a metal or plastics housing with a freely-moving metal or plastics cog wheel roller and 2 or 3 dosing nozzles for the precipitants and flocculants.
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