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A method for removing silicon from straw pulp black liquor

A straw pulp black liquor and black liquor technology, applied in the field of papermaking, can solve the problems of increasing the descaling burden of the concentrated evaporator, the decrease of the thermal efficiency of the evaporator, and the decrease of the clarity of the white liquor, etc., so as to achieve the simple and convenient silicon removal process and the elimination of the silicon interference problem , The effect of improving the thermal expansion characteristics

Inactive Publication Date: 2015-07-29
JIAMUSI AMUR PULP & PAPER
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

If the SiO in the black liquor cannot be effectively removed 2 And silicon-containing compounds, fouling will occur in the black liquor concentration evaporator, resulting in a decrease in the thermal efficiency of the evaporator, and the silicon residue will reduce the clarity of the white liquor in the causticizing process, affecting the quality of alkali recovery
[0003] The structure of silicon is glassy, ​​and it is generally difficult to remove acid and alkali. At present, the existing methods for removing silicon from straw pulp black liquor mainly include: adding CaO to the black liquor to precipitate part of the silicon, but the addition of CaO will cause concentration and evaporation The device increases the descaling burden; there is also a high concentration of CO 2 Inject into black liquor to make SiO 2 Precipitation method, but this method consumes too much CO 2 , increase the production cost; there are also antiscalants added to the black liquor to protect the evaporator, the effect is not ideal, and the production cost will also increase

Method used

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  • A method for removing silicon from straw pulp black liquor
  • A method for removing silicon from straw pulp black liquor

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] The black liquor extracted from the straw pulp was placed in a settling tank for natural settlement for 16 hours to form a supernatant liquid and a lower sedimentation layer. SiO of the supernatant 2 The content is below 0.5g / L, just send it to the evaporator for concentrated treatment. SiO in the lower sedimentation layer 2The content is 13g / L, which is sent to the second decanter centrifuge for processing. The black liquid obtained after treatment is sent to the disc centrifuge for processing, and the silicon-containing sludge obtained is sent to the slag collection tank. The clarified liquid obtained after being processed by the disc centrifuge can be sent to the evaporator for concentration, and the silicon-containing sludge obtained is also sent to the slag collection tank. Add hot water into the slag collection tank to form a silicon-containing sludge suspension with a concentration of 10%, and send the suspension to the first decanter centrifuge for processing...

Embodiment 2

[0032] The black liquor extracted from the bagasse pulp was placed in a settling tank for natural settlement for 4 hours to form a supernatant liquid and a lower sedimentation layer. The upper black liquor SiO 2 If the content is below 0.5g / L, send it to the evaporator for concentration treatment. SiO in the lower sedimentation layer 2 The content is 9g / L, and it is sent to the second decanter centrifuge for processing. The black liquid obtained after treatment is sent to the disc centrifuge for processing, and the silicon-containing sludge obtained is sent to the slag collection tank. The clarified liquid obtained after being processed by the disc centrifuge can be sent to the evaporator for concentration, and the silicon-containing sludge obtained is also sent to the slag collection tank. Add hot water into the slag collection tank to form a silicon-containing sludge suspension with a concentration of 15%, and send the suspension to the first decanter centrifuge for proce...

Embodiment 3

[0035] The black liquor extracted from wheat straw pulp is directly pumped into the disc centrifuge for treatment, the separated clear liquid is sent to the evaporator for concentration, the separated silicon-containing sludge is sent to the slag collection tank, and hot water is added to the slag collection tank water to form a silica-containing sludge suspension with a concentration of 12%. The suspension is pumped into the first decanter centrifuge for processing, and the clear black liquor obtained by centrifugation is sent back to the disc centrifuge for separation, and the obtained wet near-neutral silicon-containing waste residue can be returned to the field.

[0036] Effect of silicon removal treatment: SiO of wheat straw pulp black liquor before treatment 2 The content is 3.6g / L, after centrifugation, the clear black liquor SiO 2 The contents are all below 0.5g / L, and the silicon removal rate of wheat straw pulp black liquor is 90%.

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Abstract

The invention discloses a silica removing method for straw pulp black liquor. The silica removing method for the straw pulp black liquor comprises the following steps that (1) the straw pulp black liquor is delivered to a disc centrifugal machine, so that centrifugal processing is conducted and first clean black liquor and sludge containing silica are obtained; (2) the sludge containing the silica is delivered into a sludge collecting tank and hot water is added into the sludge collecting tank, so that sludge suspension liquid containing the silica is formed; (3) the sludge suspension liquid containing the silica is delivered to a first horizontal spiral centrifugal machine for centrifugal processing, so that second clean black liquor and waste residue containing the silica are obtained, and the second clean black liquor is delivered into the disc centrifugal machine to be processed until the content of the SiO2 in the second clean black liquor is less than 0.5g / L. According to the silica removing method for the straw pulp black liquor, no silica removing agent is added and used, a physical processing method is adopted, so that secondary interference to the following processing of the black liquor is not caused, and a silica removing process is simple; the black liquor after the silica is removed guarantees that the problem of silica interference in alkali recovery of the black liquor is solved fundamentally; the black liquor after the silica is removed has important improvement in the characteristic aspects of both viscosity and thermal expansion, and the values of the viscosity and the thermal expansion are close to those of wood pulp black liquor.

Description

technical field [0001] The invention relates to the field of papermaking, in particular to a method for removing silicon from straw pulp black liquor. Background technique [0002] The process of using straw raw materials to make pulp is a mature technology. What restricts the production of straw pulp and papermaking industry is the removal of silicon in the black liquor and the recovery of alkali. If the SiO in the black liquor cannot be effectively removed 2 And silicon-containing compounds, fouling will occur in the black liquor concentration evaporator, resulting in a decrease in the thermal efficiency of the evaporator, and the silicon residue will reduce the clarity of the white liquor in the causticizing process, affecting the quality of alkali recovery. [0003] The structure of silicon is glassy, ​​and it is generally difficult to remove acid and alkali. At present, the existing methods for removing silicon from straw pulp black liquor mainly include: adding CaO to...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): D21D5/18D21D5/00
Inventor 蓝海方红黎国康蓝洋时圣涛
Owner JIAMUSI AMUR PULP & PAPER