阅读说明：本技术 一种造纸过程中尾渣处理工艺 (Tailing treatment process in papermaking process ) 是由 李文斌 于 2020-12-31 设计创作，主要内容包括：本发明公开了一种造纸过程中尾渣处理工艺。包括以下步骤：(1)尾渣预处理；(2)上层清液处理；(3)下层重渣处理。本发明的尾渣处理工艺将尾渣重新处理,然后分成上层清液和下层重渣,上层清液可再次回到造纸工艺继续进行造纸,下层重渣再次进行处理,部分再次处理,其余剩下的部分作为塑料的原料,从而充分利用尾渣,避免了填埋和焚烧。(The invention discloses a tailing treatment process in a papermaking process. The method comprises the following steps: (1) pretreating tailings; (2) treating supernatant liquor; (3) and (5) treating lower heavy slag. The tailings are retreated by the tailings treatment process, and then the tailings are divided into upper layer clear liquid and lower layer heavy slag, the upper layer clear liquid can return to the papermaking process again to continue papermaking, the lower layer heavy slag is retreated again, part of the lower layer heavy slag is retreated, and the rest of the residual part is used as a raw material of plastics, so that the tailings are fully utilized, and landfill and incineration are avoided.)

1. A process for treating tailings in a papermaking process is characterized by comprising the following steps:

(1) pretreatment of tailings: mixing the tailings with water, adding a swelling agent, fully stirring and mixing for 40-50min, passing through a hydrapulper, standing and precipitating to obtain upper clear liquid and lower heavy slag;

(2) and (3) supernatant liquid treatment: concentrating the supernatant, placing the concentrated supernatant into a hydrapulper, and entering a subsequent papermaking process together with paper pulp;

(3) and (3) treating lower heavy slag: and (2) crushing the lower heavy slag in a crusher, then performing coarse screening and fine screening to obtain primary slag, secondary slag and floating slag, repeatedly performing the step (1) on the floating slag, performing pretreatment on the floating slag and the tailings again, and mixing the primary slag and the secondary slag to obtain the plastic processing raw material.

2. The process for treating tailings generated in the papermaking process according to claim 1, wherein the weight ratio of tailings to water in the step (1) is 1:1 to 1.5.

3. The process for treating tailings generated in the papermaking process according to claim 1 or 2, wherein the swelling agent comprises the following raw materials in parts by weight: 50-60 parts of sodium chloride, 10-15 parts of sodium sulfite and 1-3 parts of organic silicon.

4. The process of claim 3, wherein the swelling agent is added in an amount of 0.1 to 0.5 weight percent based on the tailings.

5. The process of claim 1, wherein the first slag and the second slag are mixed, added with polypropylene, carboxyl nitrile rubber and silane coupling agent, fully mixed, placed in a double-screw extruder, melted, extruded and granulated to obtain plastic particles.

6. The process for treating tailings in the papermaking process according to claim 5, wherein the raw materials comprise, by weight, 60-80 parts of polypropylene, 10-13 parts of carboxylated nitrile rubber, 10-13 parts of a mixture of primary and secondary slags, and 1-3 parts of a silane coupling agent.

Technical Field

The invention relates to a tailing treatment process in a papermaking process, and belongs to the technical field of papermaking.

Background

In the process of papermaking production, a low-concentration slag remover and a fine screen are required. In the prior art, tailings discharged by a low-concentration slag remover and a fine screen are directly discharged to a trench. The inspection shows that the low-concentration and fine-screening tailings still contain part of useful fibers, and the tailings are discharged into a trench in the prior art, so that fiber loss and waste are caused, and the production cost is increased; on the other hand, the discharged tailings contain more fibers and all belong to organic compounds, so that the content of organic matters in the sewage is increased, the sewage treatment load is greatly increased, the sewage treatment effect is influenced, and the environment is not protected.

At present, the domestic paper mill basically adopts the recycled waste paper as a main raw material for pulping and papermaking, the recycled waste paper has short fiber length after being recycled for many times, and a large amount of short fibers are lost into pulping residue pulp after the pulping process, so that a large amount of fibers are lost. The pulp making slag contains a large amount of impurities such as plastics, iron wires, broken stones and the like, and is difficult to treat, so that the pulp making slag is buried in general paper mills.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention provides a tailings treatment process in the papermaking process.

The invention is realized by the following technical scheme:

a tailings treatment process in a papermaking process comprises the following steps:

(1) pretreatment of tailings: mixing the tailings with water, adding a swelling agent, fully stirring and mixing for 40-50min, passing through a hydrapulper, standing and precipitating to obtain upper clear liquid and lower heavy slag;

(2) and (3) supernatant liquid treatment: concentrating the supernatant, placing the concentrated supernatant into a hydrapulper, and entering a subsequent papermaking process together with paper pulp;

(3) and (3) treating lower heavy slag: and (2) crushing the lower heavy slag in a crusher, then performing coarse screening and fine screening to obtain primary slag, secondary slag and floating slag, repeatedly performing the step (1) on the floating slag, performing pretreatment on the floating slag and the tailings again, and mixing the primary slag and the secondary slag to obtain the plastic processing raw material.

The tailing treatment process in the papermaking process comprises the step (1) that the weight ratio of the tailing to water is 1: 1-1.5.

The tailings treatment process in the papermaking process is characterized in that the swelling agent comprises the following raw materials in parts by weight: 50-60 parts of sodium chloride, 10-15 parts of sodium sulfite and 1-3 parts of organic silicon.

According to the tailing treatment process in the papermaking process, the addition amount of the swelling agent is 0.1-0.5 of the weight of the tailing.

The tailing treatment process in the papermaking process comprises the steps of mixing the primary slag and the secondary slag, adding polypropylene, carboxyl nitrile rubber and a silane coupling agent, fully mixing, placing in a double-screw extruder, and carrying out melting, extruding and granulating to obtain plastic particles.

The tailing treatment process in the papermaking process comprises the following raw materials, by weight, 60-80 parts of polypropylene, 10-13 parts of carboxyl nitrile rubber, 3-5 parts of a mixture of primary slag and secondary slag and 1-3 parts of a silane coupling agent.

The invention achieves the following beneficial effects:

the tailings are retreated by the tailings treatment process, and then the tailings are divided into upper layer clear liquid and lower layer heavy slag, the upper layer clear liquid can return to the papermaking process again to continue papermaking, the lower layer heavy slag is retreated again, part of the lower layer heavy slag is retreated, and the rest of the residual part is used as a raw material of plastics, so that the tailings are fully utilized, and landfill and incineration are avoided.

Detailed Description

The invention is further described below. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.

Example 1

A tailings treatment process in a papermaking process comprises the following steps:

(1) pretreatment of tailings: mixing the tailings with water, adding a swelling agent, fully stirring and mixing for 40-50min, passing through a hydrapulper, standing and precipitating to obtain upper clear liquid and lower heavy slag; the weight ratio of the tailings to the water is 1: 1;

(2) and (3) supernatant liquid treatment: concentrating the supernatant, placing the concentrated supernatant into a hydrapulper, and entering a subsequent papermaking process together with paper pulp;

(3) and (3) treating lower heavy slag: and (2) crushing the lower heavy slag in a crusher, then performing coarse screening and fine screening to obtain primary slag, secondary slag and floating slag, repeatedly performing the step (1) on the floating slag, performing pretreatment on the floating slag and the tailings again, and mixing the primary slag and the secondary slag to obtain the plastic processing raw material.

The swelling agent comprises the following raw materials in parts by weight: 50 parts of sodium chloride, 15 parts of sodium sulfite and 1 part of organic silicon. The addition amount of the swelling agent is 0.5 of the weight of the tailings.

And mixing the primary slag charge and the secondary slag charge, adding polypropylene, carboxyl nitrile rubber and a silane coupling agent, fully mixing, placing in a double-screw extruder, and melting, extruding and granulating to obtain plastic particles. The weight portions of the raw materials are 60 portions of polypropylene, 10 portions of carboxyl nitrile rubber, 10 portions of the mixture of primary slag charge and secondary slag charge and 1 portion of silane coupling agent.

According to the invention, the swelling agent is added to soften the fibers in the tailings, so that the subsequent pulping treatment is facilitated, the fibers in the tailings are extracted as far as possible, and sodium chloride, sodium sulfite and organic silicon are used as the swelling agent, so that the softening effect is good.

Example 2

A tailings treatment process in a papermaking process comprises the following steps:

(1) pretreatment of tailings: mixing the tailings with water, adding a swelling agent, fully stirring and mixing for 40-50min, passing through a hydrapulper, standing and precipitating to obtain upper clear liquid and lower heavy slag; the weight ratio of the tailings to the water is 1: 1.5;

(2) and (3) supernatant liquid treatment: concentrating the supernatant, placing the concentrated supernatant into a hydrapulper, and entering a subsequent papermaking process together with paper pulp;

(3) and (3) treating lower heavy slag: and (2) crushing the lower heavy slag in a crusher, then performing coarse screening and fine screening to obtain primary slag, secondary slag and floating slag, repeatedly performing the step (1) on the floating slag, performing pretreatment on the floating slag and the tailings again, and mixing the primary slag and the secondary slag to obtain the plastic processing raw material.

The swelling agent comprises the following raw materials in parts by weight: 60 parts of sodium chloride, 10 parts of sodium sulfite and 3 parts of organic silicon. The addition amount of the swelling agent is 0.1 of the weight of the tailings.

And mixing the primary slag charge and the secondary slag charge, adding polypropylene, carboxyl nitrile rubber and a silane coupling agent, fully mixing, placing in a double-screw extruder, and melting, extruding and granulating to obtain plastic particles. The weight portions of the raw materials are respectively 80 portions of polypropylene, 13 portions of carboxyl nitrile rubber, 13 portions of a mixture of primary slag charge and secondary slag charge and 3 portions of silane coupling agent.

Example 3

A tailings treatment process in a papermaking process comprises the following steps:

(1) pretreatment of tailings: mixing the tailings with water, adding a swelling agent, fully stirring and mixing for 40-50min, passing through a hydrapulper, standing and precipitating to obtain upper clear liquid and lower heavy slag; the weight ratio of the tailings to the water is 1: 1.2;

(2) and (3) supernatant liquid treatment: concentrating the supernatant, placing the concentrated supernatant into a hydrapulper, and entering a subsequent papermaking process together with paper pulp;

(3) and (3) treating lower heavy slag: and (2) crushing the lower heavy slag in a crusher, then performing coarse screening and fine screening to obtain primary slag, secondary slag and floating slag, repeatedly performing the step (1) on the floating slag, performing pretreatment on the floating slag and the tailings again, and mixing the primary slag and the secondary slag to obtain the plastic processing raw material.

The swelling agent comprises the following raw materials in parts by weight: 55 parts of sodium chloride, 11 parts of sodium sulfite and 2 parts of organic silicon. The addition amount of the swelling agent is 0.2 of the weight of the tailings.

And mixing the primary slag charge and the secondary slag charge, adding polypropylene, carboxyl nitrile rubber and a silane coupling agent, fully mixing, placing in a double-screw extruder, and melting, extruding and granulating to obtain plastic particles. The weight portions of the raw materials are 70 portions of polypropylene, 11 portions of carboxyl nitrile rubber, 11 portions of a mixture of primary slag charge and secondary slag charge and 2 portions of silane coupling agent.

Comparative example 1

Polypropylene, carboxyl nitrile rubber and silane coupling agent are fully mixed and then placed in a double-screw extruder, and plastic particles are prepared through melting, extruding and granulating.

The plastic granules of the examples and comparative examples were subjected to the performance test and the results are shown in Table 1.

TABLE 1 Plastic particle Performance test results

	Example 1	Example 1	Example 3	Comparative example 1
					Tensile strength MPa	81.3	80.7	80.3	70.1
Bending strength MPa	128.5	129.1	130.8	119.2
					Impact strength kJ/m2	73.1	74.2	72.9	60.9

From table 1, examples 1, 2 and 3 added a mixture of primary and secondary slag and the resulting plastics had good strength compared to comparative example 1.

The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.