US 12,404,195 B2
Process for removing silica and reducing total hardness from water
Grant Douglas, Acton (AU)
Assigned to COMMONWEALTH SCIENTIFIC AND INDUSTRIAL RESEARCH ORGANISATION, Acton (AU)
Filed by Commonwealth Scientific and Industrial Research Organisation, Acton (AU)
Filed on Jan. 8, 2021, as Appl. No. 17/144,339.
Application 17/144,339 is a continuation in part of application No. 16/645,358, previously published as PCT/AU2018/050967, filed on Sep. 6, 2018.
Claims priority of application No. 2017903640 (AU), filed on Sep. 8, 2017; and application No. 2018901121 (AU), filed on Apr. 5, 2018.
Prior Publication US 2021/0130211 A1, May 6, 2021
This patent is subject to a terminal disclaimer.
Int. Cl. C02F 5/08 (2023.01); C02F 1/28 (2023.01); C02F 1/42 (2023.01); C02F 1/66 (2023.01); C02F 5/02 (2023.01); C02F 101/10 (2006.01); C02F 101/30 (2006.01); C02F 101/32 (2006.01); C02F 101/36 (2006.01)
CPC C02F 5/083 (2013.01) [C02F 1/281 (2013.01); C02F 1/42 (2013.01); C02F 1/66 (2013.01); C02F 5/02 (2013.01); C02F 2101/10 (2013.01); C02F 2101/301 (2013.01); C02F 2101/32 (2013.01); C02F 2101/36 (2013.01); C02F 2101/40 (2013.01); C02F 2303/16 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A process for removing silica and reducing total hardness of a natural or waste water containing silica and scale-forming ions, the process comprising: adding (i) magnesium hydroxide or a precursor of magnesium hydroxide and (ii) a soluble aluminate compound or a precursor of aluminate to said water while maintaining the pH of said stream at pH >8 to produce layered double hydroxide in situ, wherein the layered double hydroxide contains the scale-forming ions in a lattice of the layered double hydroxide and silica is incorporated in the lattice of the layered double hydroxide as an interlayer anion and/or bound by the layered double hydroxide via one or more binding modes, wherein the process further comprises a recycling and regeneration step;
wherein the recycling and regeneration step comprises:
a) removing layered double hydroxide from the process;
b) regenerating and/or recycling at least a portion of the layered double hydroxide removed from the process to form regenerated and/or recycled layered double hydroxide; and
c) reintroducing the regenerated and/or recycled layered double hydroxide back into the process.