In-line production of silica for retention purposes

Abstract

The present invention discloses an on-line production method for supplying a retention aid to a liquid stream of a stock suspension and a short circuit of a paper machine, wherein the method comprises the steps of: (i) providing a liquid stream of the stock suspension; and ( ii) feeding at least one additive to the liquid stream of said stock suspension, wherein said retention aid is formed directly in said stock suspension. The at least one additive can be added to the stock suspension, for example, as a liquid stream. The retention aids provided by the method of the present invention can further improve the control of the dewatering rate and consequently the strength properties of the paper. By this method, it is provided that the retention aid is formed directly in the stock suspension. This eliminates the need to transport eg pre-made retention aid solutions and thus retention aids can be formed in a very cost effective manner. Furthermore, since the retention aid is formed directly in the stock suspension, it can adhere very quickly and efficiently to fine particles or to fillers in said stock suspension, and thus a more effective effect can be achieved.

Description

technical field [0001] This document relates to an in-line production process for a papermaking process and a boardmaking process, and for the simultaneous delivery of at least one additive into the stock suspension of a paper or board machine to form a retention agent (retention agent) method. Background technique [0002] Silica is commonly used alone or with another ingredient as a retention chemical or agent to retain fine materials, mainly dissolved colloidal substances, chemicals, fines (fines, fines) and filler particles. Silica can be produced in many ways, such as dialysis, electrodialysis, neutralization, peptization, and one common commercial method is by sodium metasilicate (with the common name sodium silicate (Na 2 SiO 3 ), which is also known as ion exchange of water glass). Other methods are also described in the literature, such as the treatment of water glass with acid followed by the formation of silica in tanks or containers. [0003] However, these ...

AI Technical Summary

Problems solved by technology

The solids content of the readymade colloidal silica product is e.g. very low, which leads to expensive and environmentally unfriendly transport of the product into paper / board mills and higher CO 2 the footprint

Another issue associated with the manufacture of colloidal silica is that the process must be optimized to obtain a stable product that does not precipitate or flocculate, which can affect the properties of colloidal silica

Furthermore, the field method has some disadvantages

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