Process for treating and reclaiming black paper-making liquid generated by alkali pulping

A papermaking black liquor and alkaline pulping technology, which is applied in the regeneration of alkali liquor, etc., can solve the problems of large floor area, low operation rate of treatment engineering facilities, and large project investment.

Inactive Publication Date: 2003-02-19
阮键华
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  • Summary
  • Abstract
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  • Application Information

AI Technical Summary

Problems solved by technology

For example, the alkali recovery method (combustion method) is an effective method to control black liquor pollution, but the project investment is too large and the operating cost is too high, which cannot be afforded by small and medium-sized paper-making enterprises.
Some straw pulp enterprises use the acid analysis lignin method to treat black liquor, but this method req

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0005] At a temperature of 30°C, add 20 kg of a 1% sodium polyacrylate solution into 1000 kg of reed pulp black liquor with a pH of 10 Baume and a pH of 14, stir for 2 minutes, and then add 60 kg of a 20% calcium chloride solution , stirred for 5 minutes, the black liquor solidifies and precipitates cotton-like lignin. After the lignin is separated, the filtrate, that is, the supernatant, is brown and transparent, with a pH value of 8, and is used for reprocessing the black liquor; the lignin can be used as a soil improver, organic fertilizer, filler, etc. after dehydration;

Embodiment 2

[0007] At a temperature of 30°C, add 30 kg of a cationic polyacrylamide solution with a concentration of 0.5% to 1000 kg of straw pulp black liquor at 11 degrees Baume and a pH value of 14, stir for 3-5 minutes, and then add a polymerized polyacrylamide solution with a concentration of 20%. 60kg of aluminum chloride solution was stirred for 5 minutes, and the black liquor solidified and precipitated cotton-like lignin. After the lignin is separated, the filtrate is clear and transparent, and the pH value is 7, which is used to treat the mid-stage wastewater, and the treatment of the lignin is the same as in Example 1;

Embodiment 3

[0009] At a temperature of 30°C, add 30 kg of acrylamide solution with a concentration of 1% to 1000 kg of grass pulp black liquor with a pH value of 14 at 11 degrees Baume, stir for 3 minutes, and then add 60 kg of a 20% polyaluminum chloride solution , stirred for 5 minutes, the black liquor solidified and precipitated tofu flower-type lignin. After the lignin is separated, the filtrate is brown and transparent, and the pH value is 9. It is used as water for wet dedusting and desulfurization of the chimney, and the treatment of the lignin is the same as in Example 1.

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PUM

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Abstract

A process for reclaiming the black paper-making liquid generated by alkali pulping method includes adding flocculant, stirring for 2-5 min, adding assistant, stirring for 3-8 min to educe out lignin, filtering, dewatering lignin for using it as fertilizer, soil improver filler, etc, and further processing supernatant.

Description

technical field [0001] The invention relates to a method for treating and comprehensively utilizing the black liquor of alkaline pulping and papermaking, which belongs to the regeneration category of pulping alkali liquor. Background technique [0002] There are more than 6,700 pulp and paper enterprises in my country, and the industrial output ranks third in the world, but the average size of the enterprises is only 4,000T / a. The discharge of papermaking and paper products industrial wastewater at or above the county level in the country accounts for 11% of the national industrial wastewater discharge, and the CODcr discharged in the wastewater accounts for more than 40% of the national total discharge. The main pollution of pulping and papermaking enterprises comes from black liquor (pulping waste liquor is called black liquor because of its black color), and the pollution load in black liquor accounts for 80-90% of the sewage of the whole plant. The composition of black ...

Claims

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Application Information

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IPC IPC(8): D21C11/04
Inventor 阮键华新阳王雄
Owner 阮键华
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