SU730913A1 - Sulphate pulp washing method - Google Patents

Description

one

This invention relates to the pulp and paper industry and concerns a method for washing sulphate pulp for paper and paperboard.

There is a known method of washing sulphate pulp by means of stepwise processing of pulp about the liquid supplied by the countercurrent using the condensates of the cooking and evaporating shops using washing liquid {.

However, this method does not completely eliminate the consumption of fresh water for washing the pulp and reduce the volume of wastewater. In addition, when using condensates it is necessary to use closed equipment.

The purpose of the invention is to eliminate the consumption of fresh water for the pulping operation and to reduce the volume of wastewater.

This goal is achieved by the fact that biologically purified waste water having a pH of 6.5-8.5, BPKg 5-60 mg / l of Og is supplied as a washing liquid to the last stage of cellulose treatment.

A method for washing pulp is isgaltan under laboratory conditions.

Example, Under laboratory conditions, a stepwise washing process is applied to pressure filters. Production of cellulose is used for & 1: .- 1SU:.; 1Sgyu 35 units. Kappa, Not the last stage of washing serves

0 biologichas -: purified waste soKU.

Yes, the same cellulose is washed under similar conditions, but the last stage 15 of the washing is supplied by the condensate of the evaporation plant,

The temperature of the wash liquids 80 --9 O -C.

The quality indicators of the 20 liquids in Table. one,.

Efa) ect os: rb washing the cellulose at the use of biology and biochemistry: day laboratories and evaporation plant condensate 98%, 25 Density is selected

from each step is given in tablc2,

lis table. 2 it follows that the density of calscals, selected mx, into the system of regeneration of the hickshats, during the pro- duction of cellulose with biologically treated wastewater, is higher than when it is washed with condensate from the evaporation plant (1,106-1,105 instead of 1,104).

In accordance with the methods proposed by known methods, the pulp is milled on an IRA mill to 60 SR, cast on a LA-1 casting weight of 75 g / m and carried out their physical and mechanical tests.

Testing of cellulose castings in accordance with GOST 13525.8-68, 13525.3-68, 13525., 13525.1-68.

The test results are given in table, 3,

For the physico-mechanical tests of the Research Institute of Cardboard, cellulose, which has been developed by the proposed and well-known methods, is ground to brown brown glue in an amount of 0.6% by weight of absolutely dry fiber and alumina.

to pH 8; Grinding and reflux is carried out on the registered water of the cardboard factory of the Selenginsk CKK. Experiment casting cardboard weighing 200 g / m

The result of physical and mechanical testing of cardboard castings according to GOST

, 13648.7-69, 13525.2-68.122605-67,

10711-63 are given in table. four,

Thus, the efficiency of washing the cellulose with condensate and biologically purified water is the same, but the density of the filtrate for regeneration is higher when using biologically purified water. The physicomechanical indicators of cellulose, washed with condensate and biologically cleaned in dyne, and cardboard made from it meet the requirements of GOST and TU,

The use of biologically treated wastewater eliminates the consumption of fresh water for washing pulp and reduces the discharge of contaminants into the reservoir with treated wastewater and the volume of wastewater by 2, 8 million. m YEAR.

0Expecting for economic effect

when washing sulphate unbleached pulp with biologically purified wastewater in relation to the Selenga CTC will be 227 thousand rubles,

 in year.

Table 1

Indicators

pH, units BOD (mg / l COD, mg / l

Alkalinity, g / l Na Dry residue, g / l including;

mineral substances, g / l

organic matter, g / l

suspended solids, mg / l

o Chromaticity, Pgap

Acid capacity mg / l

6.95 264.0

1024

0.018 0.610

0.135

1,1001,300

0.026Of320 0.475

23.0

24.3

25.0 000 2000 1000 368 1000 450

Burst resistance, kgf / cm 7.0

Resistance to fracture, ch.d.p.250

Resistance to annular compression, kg / cm 2.0

Table

Claims (1)

Table 4 7309 Formula of the invention A method of washing sulphate pulp tfyxeM with stepwise treatment of cellulose mass with a washing liquid supplied by a countercurrent, characterized in that, in order to eliminate the consumption of fresh water for the operation of cellulose and reduce the volume of water, 138 to the last stage of cellulose 5 As a washing liquid, biologically purified waste water pH 6.5-8.5 is fed, BnKj 560 mg / l Ot. , Sources of information taken into account in the examination of i. U.S. Patent 3,830,688, D 21 C 9/02, 1974.