Treatment of Pulp

a technology of pulp and pulp pulp, applied in the field of pulp treatment, can solve the problems of large quantity of bleaching agent, increased production cost, inefficient use of large amount of bleaching agent, etc., and achieve the effect of reducing waste streams, reducing production costs, and maintaining the balance of the plan

Inactive Publication Date: 2008-10-30
IMERYS MINERALS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0019]In a further aspect of the present invention some or all of the mixed aggregated material resulting from step (c) may be combined with the bleached coarse fraction resulting from step (b) according to the first aspect of the invention, in order to make paper. This aspect of the invention advantageously results in minimising the various waste streams and helps to maintain the balance of the plant in which the paper making process is being carried out.
[0020]There are numerous other advantages associated with the present invention. Although bleaching may be performed in the normal manner, the bleaching equipment may be smaller in size compared to conventional bleaching units, due to the smaller mass to be bleached. In addition, as the coarse fraction will generally dewater more efficiently than the original pulp, the devices...

Problems solved by technology

There are numerous disadvantages associated with bleaching pulp in order to increase the whiteness of paper.
For example, in bleaching pulp, large quantities of bleaching agent are required.
This contributes to increased production cost, as well as being an inefficient use of large amounts of bleaching agents.
Balancing these aspects has hitherto proven difficult.
One of the other environmental issues relating to the production of paper concerns the aqu...

Method used

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Examples

Experimental program
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Effect test

examples

Test Methods

Brightness

[0057]The ISO brightness of coated paper was measured by means of an Elrepho Datacolour 2000™ brightness meter fitted with a No. 8 filter (457 nm wavelength), according to ISO 2470: 1999 E.

Brightness Cakes

[0058]Brightness cakes or pads were made according to standard methods. More specifically, the pads are formed by taking about 5 g by dry weight of sample and diluting to about 1%. The sample is dewatered on a 15 cm diameter Buchner funnel to give pads of approximately 280 g basis weight. The pads are then pressed on a handsheet press for about 2 minutes, using three standard blotters per pad. The sequence on the press is: 3 blotters; filter paper; sample; metal plate. After pressing, the samples are dried between two fresh blotters on a drying drum with a surface temperature of 80° C. The filter paper is removed from the dry pad and the brightness is measured from each side wherein the top is the side away from the filter paper and filter is the side against ...

example a

Pulp Splitting

[0068]Pulp splitting was carried out using the OptiThick™ device which is commercially available from Metso in Inkeroinen, Finland, under the following conditions:

Speed—600 m / min;

Head Box Feed—40 litres / s;

Head Box Feed Pressure—21 kPa;

Feed Temperature—60° C.;

[0069]Wire—Kraftex CD288 S-39, fabric 3052203.1.

[0070]The properties of the SGW feed and the coarse fraction obtained after pulp splitting are set out in Table 1 below.

TABLE 1B-B-BrightnessCSFMcN +McN +B-McN +B-McNSample(% ISO)(ml)30 (%)50 (%)200 (%)fines (%)SGW feed68.2418.413.927.250.5Coarse62.715919.227.032.821.0fraction

example b

Bleaching of the Coarse Fraction

[0071]The Stone GroundWood (SGW) coarse fraction which was obtained according to Example A above, was pretreated with 0.1 wt % diethylenetriaminepentaacetate (DPTA, available from E.G. Merck) and thickened to 25 wt % solids using a vacuum funnel and centrifuge under standard conditions. A series of chemical doses of hydrogen peroxide was used to bleach 30 g samples in plastic bags. Bleaching was carried out at 70° C. (maintained in a water bath), using 25 wt % solids and a reaction time of 90 minutes. Following this, the samples were acidified to pH 5.5 with H2SO4.

[0072]Brightness cakes of each of the samples obtained were made and the results according to Table 2 were obtained which compare the original feed with the coarse fraction.

TABLE 2ResidualExamplePeroxideNaOHSilicateDTPApHpHperoxideB'nessB'nessNumber(wt %)(wt %)(wt %)(wt %)startfinal(wt %)startfinalFeedSGW11.51.351.20.110.98.80.2168.273.922.01.61.50.110.99.00.6468.277.933.02.12.10.110.89.40.9...

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Abstract

A method of treating a fibre pulp mixture comprises: (a) separating the fibre pulp mixture into at least two fractions to form a coarse fraction and a fine fraction; (b) bleaching the coarse fraction from (a); and (c) precipitating an alkaline earth metal carbonate in the fine fraction from (a). The products from steps (b) and (c) may combined in an integrated paper making process.

Description

FIELD OF THE INVENTION[0001]The present invention relates to methods for treating pulp for use in the production of paper and paper products, in particular super calendered (SC) paper. The present invention also relates to products obtained by said methods.[0002]The term “paper” should be understood to mean all forms of paper, including board, card, paperboard, and the like.BACKGROUND[0003]One of the most important characteristics of paper is its degree of whiteness. Generally, and depending on the application, the whiter the paper, the higher the selling price. In order to obtain whiter papers, efforts have been directed to treatment of pulp by subjecting it to bleaching agents such as alkaline hypochlorite.[0004]There are numerous disadvantages associated with bleaching pulp in order to increase the whiteness of paper. For example, in bleaching pulp, large quantities of bleaching agent are required. This contributes to increased production cost, as well as being an inefficient use...

Claims

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Application Information

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IPC IPC(8): D21C9/00D21H17/63D21C9/10D21H15/02D21H17/00D21H17/64D21H17/67D21H17/70D21H25/14
CPCD21C9/10D21H15/02D21H17/675D21H17/70D21H25/14
Inventor LIKITALO, MIKKO HENRIKTOIVONEN, HANNU OLAVI ENSIO
Owner IMERYS MINERALS
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