Patents Examined by Bendoit Castel
  • Patent number: 4131545
    Abstract: Phosphate containing basic aluminum solutions are provided by reaction aluminum sulphate solution with phosphoric acid, adding chloride, basifying by precipitation of calcium sulphate from solution and cooling the resultant solution in a controlled manner. Preferably addition of chloride and basification occurs at a temperature of C and the solution is cooled to below C soon after the basifying salts have been introduced. The solutions, preferably diluted to an aluminum content of 1 to 2% Al.sub.2 O.sub.3 are useful for clarifying water and dewatering sewage sludge.
    Type: Grant
    Filed: May 2, 1977
    Date of Patent: December 26, 1978
    Assignee: Laporte Industries Limited
    Inventors: William H. Redmayne, David Berry