In-line production of silica for retention purpose

Abstract

The present invention discloses an in-line production method for providing a retention agent into a liquid flow of a stock suspension and into the short circulation of a paper making machine, wherein the method comprises the steps of: (i) providing a liquid flow of a stock suspension; and (ii) feeding at least one additive into said liquid flow of the stock suspension, wherein said retention agent is formed directly in said stock suspension. The at least one additive may be added to the stock suspension e.g. as a liquid flow. The retention agent provided by the method of the invention may further improve the control of the dewatering rate and subsequently the strength properties of the paper. By this method there is provided a way of forming a retention agent directly into the stock suspension. The need of transporting, e.g. a readymade solution of a retention agent is thereby abolished, and thus the retention aid may be formed in a very cost-efficient way. Further as the retention agent is formed directly into the stock suspension it may very quickly and efficiently adhere to the fine particles, or the filler in the stock suspension and thus a more efficient effect may 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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