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US 2013/0171051 A1Published application
Novel precipitated silica production process
AssigneeRhodia Operations
InventorsMalika Clouin, Sylvaine Neveu, Joël Racinoux
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Abstract
A precipitated silica production process that includes a precipitation reaction between a silicate and an acid is described, in which the acid used in at least one of the steps of the process is a concentrated acid.
Claims27
A process for preparing precipitated silica, the process comprising conducting a precipitation reaction between a silicate and at least one acid, whereby a suspension of precipitated silica is obtained, followed by separation and drying of this suspension, wherein:
- the precipitation reaction is carried out in the following way:
- (i) forming an initial stock comprising a silicate and an electrolyte, wherein a concentration of silicate (expressed as SiO2) in said initial stock is less than 100 g/l and, optionally, wherein concentration of electrolyte in said initial stock is less than 19 g/l,
- (ii) adding an acid to said stock until a pH value of the reaction medium of at least 7.0, is obtained,
- (iii) simultaneously adding an acid and a silicate to the reaction medium,
- (iv) adding an acid to the reaction medium, optionally until a pH value of the reaction medium of between 3.0 and 6.5 is obtained,
- drying a resulting suspension,
- and wherein, in at least step (iii), the acid used is a concentrated acid.
4 more elements
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Dependencies are inferred from the claim text.