Process for preparing precipitated silica comprising a high compaction step

Patent metadata

Field	Value
Publication number	US-10865114-B2
Application number	US-201314386015-A
Country	US
Kind code	B2
Filing date	Mar 21, 2013
Priority date	Mar 22, 2012
Publication date	Dec 15, 2020
Grant date	Dec 15, 2020

Abstract

A process for preparing precipitated silica comprising a reaction of a silicate with an acidifying agent to obtain a suspension of precipitated silica, followed by a step of separation to obtain a cake and a step of drying said cake, wherein a step of compaction of said cake at a pressure greater than 10 bars is carried out between the step of separation and the step of drying.

First claim

The invention claimed is:

1. A process for preparing precipitated silica, the process comprising;
reacting a silicate with an acidifying agent to obtain a precipitated silica suspension,
separating a precipitated silica from the suspension by a single separating step to obtain a cake, wherein the separating step consists of filtration, optional washing, and compacting on a filter press, and
drying the said cake,
wherein compacting said cake is carried out at a pressure between 10 and 45 bars and
wherein, after compacting and before drying, said cake has a dry matter level between 29 and 35 wt %.

2. The process according to claim 1 , wherein compacting said cake is carried out at a pressure between 15 and 45 bars.

3. The process according to claim 1 , wherein compacting said cake is carried out at a pressure of at least 20 bars.

4. The process according to claim 1 , not comprising a disintegrating step.

5. The process according to claim 1 , wherein the drying step is not carried out by atomization.

6. The process according to claim 1 , further comprising a lump breaking step which is carried out between the compacting step and the drying step.

7. The process according to claim 1 , wherein the dried cake is subjected to a grinding step.

8. The process according to claim 1 , wherein the dried cake is subjected to an agglomerating step.

9. The process according to claim 1 , wherein compacting said cake is carried out at a pressure between 20 and 35 bars.

10. The process according to claim 1 , wherein, after compacting and before drying, said cake has a dry matter level between 29 and 32 wt %.

11. The process according to claim 7 , wherein the dried cake that has been subject to the grinding step is subjected to an agglomerating step.

Assignees

• Rhodia Operations

Inventors

• Neveu Sylvaine
• Pinault Anne-Laure

Classifications

• C01B33/193 Primary

  of aqueous solutions of silicates · CPC title

• C01B33/124 Primary

  Preparation of adsorbing porous silica not in gel form and not finely divided, i.e. silicon skeletons, by acidic treatment of siliceous materials · CPC title