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Process for recovering organic acid from bleaching liquors

A technology of bleaching liquid and organic acid, which is applied in the circulation of bleaching liquid, recovery of organic acid, and alkaline filtrate. It can solve the problems of loss, waste water, unused organic acid, etc., and achieve the effect of reducing washing loss.

Inactive Publication Date: 2004-12-08
CHEMPOLIS OY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, these methods do not take advantage of the organic acids produced in bleaching; instead, these acids are lost in alkaline bleaching because they immediately react with the sodium hydroxide used in bleaching to form salts
Such salts are also undesirable in traditional methods as they generate waste water

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0046] Cellulose obtained from wheat straw and produced in a formate-based process (bound acids washed out in the unbleached pulp: 0.9% formic acid and 2.4% acetic acid) was used. Unbleached pulp is bleached in an alkaline peroxide bleaching step with KOH to adjust the pH. The amount of hydrogen peroxide used was 3.0% of dry pulp and that of KOH was 11.9% of dry pulp. 71.4 grams of material were taken from the pulp alkaline peroxide bleaching filtrate (initial concentration 12%, final pH value 10.9), and neutralized to pH 2 with 0.5M nitric acid. The amount of nitric acid consumed was 52.4 milliliters, or 0.03 mole, and the nitric acid consumption (calculated by 100% nitric acid) per 1000 kg of bleaching filtrate was 23.1 kg (367 moles).

[0047] The amount of fertilizer per 1000 kg of bleaching filtrate is: Potassium (K) 10.0 kg and Nitrogen (N) 4.1 kg. The amount of fertilizer per 1000 kg dry pulp is K=84 kg and N=35 kg.

[0048] sour

Embodiment 2

[0050] Cellulose obtained from awn ( Miscanthus sinensis ) and produced in the formate-based process (bound acids washed out in the unbleached pulp: 1.2% formic acid and 2.4% acetic acid) was used. Unbleached pulp is bleached in an alkaline peroxide bleaching step with KOH to adjust the pH. The amount of KOH used in the alkaline extraction stage was 8.4% of the dry pulp and the amount of hydrogen peroxide was 0.75% of the dry pulp. After the alkaline extraction stage (initial concentration 12%), two hydrogen peroxide stages (concentration 10%) were carried out, the amount of hydrogen peroxide used was 2.5% of the dry pulp volume in the first stage and 2.5% in the second 2.0% of dry pulp volume in stage. 100 g of feed was taken from the bleach filtrate (final pH 11.1) obtained from the alkaline extraction stage of pulp bleaching, then neutralized to pH 7 with 0.8M phosphoric acid and from pH 7 to pH 0.5M with nitric acid 2. Consumed phosphoric acid (H 3 PO 4 ) is 9.2 milli...

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Abstract

The invention relates to a process for treating bleaching liquors from pulping processes based on organic acids. The process is characterized in that inorganic acid, such as nitric acid, phosphoric acid and / or sulphuric acid, is added into a bleaching liquor obtained from the bleaching or a stage closely associated with bleaching, whereby organic acids contained in the bleaching liquor are released into the bleaching liquor. The organic acids are then separated from the bleaching liquor and recycled to the cooking stage to be used as cooking chemicals. The nitrogen-, phosphor- and / or sulphur-containing product thereby produced, from which organic acids have been separated, is recovered to be used as a fertilizer or as raw material for a fertilizer.

Description

technical field [0001] The present invention relates to pulping processes based on organic acids and in particular to the recovery of organic acids from bleaching liquors such as alkaline filtrates obtained from bleaching or bleaching-related stages and from wash filtrates. At the same time, the method of the present invention also produces valuable fertilizer by-products. The invention also relates to the circulation of bleaching solutions. The invention is suitable for pulping processes based on organic acids, especially formic and / or acetic acid, where herbs or trees are used as raw material. The invention is also applicable to pulping processes using other solvents and reagents. Background technique [0002] Organic acids are generated in all pulping processes, but the utilization of these acids remains unresolved. Organic acids are often detrimental in traditional methods and consume the base used in these methods. Organic acids are formed not only in the cooking, e...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C05F7/02D21C11/00
CPCC05F7/02Y10S210/924D21C11/0007D21C11/0028Y10S210/928
Inventor 帕西·卢素派威·卢素艾萨·卢素朱哈·安提拉
Owner CHEMPOLIS OY