Processes for paper manufacture, useful for incorporating paper waste requiring a basic treatment into paper products

Abstract

Processes for manufacturing a paper product from cellulose pulp, part of which comes from a broke and part of which comes from a fresh pulp are provided. The processes involve first redissolving in a broke pulper, with stirring and in an alkaline medium, cellulose fibers contained in said broke to form a broke pulp. Next, the broke pulp is brought to a concentration and a pH close to that characteristic of the fresh pulp by (1) diluting said broke pulp with a white water and (2) acidifying said broke pulp by injecting carbon dioxide into said broke pulp after the broke pulp has left the broke pulper and before admixing said broke pulp with said fresh pulp. Then the broke pulp is admixed with the fresh pulp to form a pulp mixture and the pulp mixture is dewatered to form a paper product and a white water.

Description

[0001] (I) Field of the Invention[0002] The present invention relates to improved processes for manufacturing paper products. In particular, the invention relates to processes that incorporate paper waste, which requires a basic treatment, and particularly "brokes" into paper products.[0003] (II) Description of the Related Art[0004] The papermaking process comprises two successive and separate parts. The first part is the preparation of the paper pulp. In this part, the paper pulp is manufactured from various fibrous materials containing cellulose (such as wood and / or annual plants) using chemical agents and / or mechanical actions.[0005] The second part is the manufacture of the paper. The term "paper" denotes a paper product, including but not limited to paper for use in graphics, packaging paper, domestic paper, various special papers, as well as boards and other such products. The terms "paper" and "paper product" will be employed interchangeably in the rest of the text.[0006] The...

AI Technical Summary

Benefits of technology

0047] By injecting the carbon dioxide into the broke pulp after the broke pulp has left the broke pulper and before admixing the broke pulp with the fresh pulp, the invention avoids certain disadvantages associated with injecting carbon dioxide directly into the broke pulper, such as unsatisfactory mixing of the carbon dioxide with the medium to be treated. Such approach consumes time and carbon dioxide for a mediocre result.

0048] In addition, by introducing carbon dioxide at one or more point

Problems solved by technology

However, none of these processes propose or suggest the use of carbon dioxide as a pH regulator in the broke circuit.

However, it provides no solution to the problem of achieving fine and flexible pH regulation, tailored to the constraints of the various steps of the broke treatment that is easy to implement, both in continuous broke treatments and in batch broke treatments, and at any tempe

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