Process for production of pcc
AssigneeOmya Development AG
InventorsKaare Hvid Hansen, Mogens Pedersen
Life of this patent
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Abstract
The present invention relates to a process of preparing precipitated calcium carbonate (PCC) in a low energy intensity reactor in such a manner that the amount of solids in the PCC product can be raised to 35% or more without performing a dewatering step. The process comprises performing in parallel and in two or more separate reaction vessel the steps of contacting calcium hydroxide with a gas comprising carbon dioxide to allow formation of calcium carbonate, and adding calcium oxide, lime or dry calcium hydroxide or a combination of any of the three to a part of the resulting mixture of calcium hydroxide and calcium carbonate. The invention further provides a specialized reactor system as well as the use of this reactor system in the manufacture of PCC.
Claims22
A process for production of precipitated calcium carbonate by carbonation of calcium hydroxide, comprising performing in parallel and in two or more separate reaction vessels the steps of:
- i) contacting calcium hydroxide with a gas comprising carbon dioxide to allow formation of calcium carbonate, and
- ii) adding calcium oxide, lime or dry calcium hydroxide or a combination of any of the three to a part of the resulting mixture of calcium hydroxide and calcium carbonate;
- in such a way that continuous or non-continuous circulation between the two or more reaction vessels are allowed.
2-70. (canceled)
A process for increasing the dry-matter content of a precipitated calcium carbonate product prepared by carbonation of calcium hydroxide, said process comprising performing in parallel and in two or more separate reaction vessels the steps of:
- i) contacting calcium hydroxide with a gas comprising carbon dioxide to allow formation of calcium carbonate, and
- ii) adding calcium oxide, lime or dry calcium hydroxide or a combination of any of the three to a part of the resulting mixture of calcium hydroxide and calcium carbonate;
- in such a way that continuous or non-continuous circulation between the two or more reaction vessels is allowed.
A reactor system comprising:
- a) optionally a water inlet,
- b) a gas inlet, and
- c) a recirculation loop, comprising an inlet for addition of calcium oxide, lime dry calcium hydroxide or a combination of any of the three and, optionally, a water inlet.
Dependencies are inferred from the claim text.