阅读说明：本技术 一种碱液循环使用的处理方法 (Treatment method for recycling alkali liquor ) 是由 胡小东 刘红 刘潘 官磊 唐进 罗仁义 陈光海 于 2020-12-28 设计创作，主要内容包括：本发明公开了一种碱液循环使用的处理方法,包括如下步骤：1)将粘胶纤维生产工艺残余回收的硫酸钠溶解为浓度5％-20％的粘胶纤维硫酸钠废液；2)硫酸钠废液进行多效蒸发浓缩结晶,结晶后进行pH调节；3)加入除盐水去除杂质过滤；4)将过滤后的硫酸钠溶液通入双极膜电渗析膜组器的硫酸钠流道中,最后制得硫酸溶液和氢氧化钠溶液；5)硫酸溶液返回步骤2)用于多效蒸发浓缩利用,氢氧化钠溶液经过纳滤膜过滤返回粘胶纤维生产工艺中用于黄化溶解碱、一浸碱液和二浸碱液的调配。本发明通过对粘胶纤维生产产生的产物Na-2SO-4进行回收处理生成酸液和碱液重复利用,变Na2SO-4废为宝,同时大大降低烧碱使用,达到碱液循环使用的目的。(The invention discloses a treatment method for recycling alkali liquor, which comprises the following steps: 1) dissolving the sodium sulfate recovered from the viscose fiber production process into viscose fiber sodium sulfate waste liquid with the concentration of 5-20%; 2) carrying out multi-effect evaporation, concentration and crystallization on the sodium sulfate waste liquid, and adjusting the pH value after crystallization; 3) adding desalted water to remove impurities and filtering; 4) introducing the filtered sodium sulfate solution into a sodium sulfate flow channel of a bipolar membrane electrodialysis membrane group device to finally prepare a sulfuric acid solution and a sodium hydroxide solution; 5) the sulfuric acid solution is returned to the step 2) for multi-effect evaporation concentration utilization, and the sodium hydroxide solution is filtered by a nanofiltration membrane and returned to the viscose fiberThe vitamin production process is used for blending etiolation dissolving alkali, primary leaching alkali liquid and secondary leaching alkali liquid. Product Na produced by viscose fiber production according to the invention 2 SO 4 The acid liquor and the alkali liquor generated by the recovery treatment are recycled and changed into Na2SO 4 The waste is used as valuable, and simultaneously, the use of caustic soda is greatly reduced, thereby achieving the purpose of recycling the alkali liquor.)

1. A treatment method for recycling alkali liquor is characterized by comprising the following steps: 1) dissolving the sodium sulfate recovered from the viscose fiber production process into viscose fiber sodium sulfate waste liquid with the concentration of 5-20%; 2) carrying out multi-effect evaporation, concentration and crystallization on the sodium sulfate waste liquid, and adjusting the pH value after crystallization; 3) adding desalted water to remove impurities and filtering; 4) introducing the filtered sodium sulfate solution into a sodium sulfate flow channel of a bipolar membrane electrodialysis membrane group device, and then introducing desalted water into an acid flow channel and an alkali flow channel of the bipolar membrane electrodialysis membrane group device to finally prepare a sulfuric acid solution and a sodium hydroxide solution; 5) the sulfuric acid solution is returned to the step 2) for multi-effect evaporation concentration utilization, and the sodium hydroxide solution is filtered by a nanofiltration membrane and returned to the viscose production process for blending of the etiolation dissolving alkali, the primary leaching alkali solution and the secondary leaching alkali solution.

2. The method for treating the recycled alkali liquor as claimed in claim 1, wherein the residual sodium sulfate obtained by filtering the sodium hydroxide solution with the nanofiltration membrane in the step 5) is returned to the step 3) for recycling.

3. The method for recycling alkali liquor in accordance with claim 1, wherein sodium sulfate in step 1) is directly dissolved by demineralized water.

4. The method for treating alkali liquor recycling according to claim 1, wherein the specific process of step 2) is as follows: the viscose waste liquid is crystallized after being concentrated and then is separated by a centrifuge, so as to obtain powdery solid containing sodium sulfate, zinc sulfate and sulfuric acid and concentrated sulfuric acid solution, the concentrated sulfuric acid solution is directly conveyed to an acid bath process in the viscose production process through a pipeline, and the powdery solid containing the sodium sulfate, the zinc sulfate and the dilute sulfuric acid is placed in a transfer tank for the next process.

5. The method for treating alkali lye for recycling according to claim 4, wherein the specific process of step 3) is to add demineralized water into the intermediate tank to dissolve the powdery solid, thereby obtaining a solution containing 5% -30% of sodium sulfate, zinc sulfate and sulfuric acid.

6. The method for recycling alkali liquor as claimed in claim 5, wherein in step 3), the dissolved solution is sequentially subjected to primary filtration, secondary primary filtration, ion exchange filtration and pp microfiltration fine filtration.

7. The treatment method for recycling alkali liquor as claimed in claim 6, wherein the filtration process in step 3) comprises settling in a preparation tank, filtering in a primary bag filter, secondary settling in the preparation tank, secondary filtering in the bag filter, primary adsorption in a resin tower and secondary adsorption in the resin tower.

8. The treatment method for recycling alkali liquor as claimed in claim 7, wherein the operation of settling the blending tank is as follows: and (3) adding alkali into the dissolved solution to neutralize to form a weakly alkaline environment, forming solid flocculent precipitate by impurity metal ions, carrying out precipitation, sedimentation and separation, discharging and recycling the physically precipitated precipitate by utilizing a sewage discharge outlet of a U-shaped sewage discharge device, and pumping out supernate to enter a post-filtering process.

Technical Field

The invention relates to the technical field of viscose fiber production, in particular to a treatment method for recycling alkali liquor.

Background

In the production process of viscose fibers, a plurality of procedures such as primary impregnation, secondary impregnation, tertiary impregnation, yellowing dissolution and the like of pulp all need to use caustic soda to prepare alkali liquor with proper concentration, so the caustic soda usage amount in the whole process flow is huge, and the cost is high; while the product Na is produced in the subsequent process₂SO₄Also adopts a low-price selling mode to process, and the Na is generated₂SO₄Is discarded in large quantities.

Disclosure of Invention

The technical problems to be solved by the invention are that the existing viscose fiber production process needs to use a large amount of caustic soda, the cost is high, and meanwhile, the product Na₂SO₄A large amount of waste is used, and the aim is to provide a treatment method for recycling alkali liquor, namely a product Na produced by viscose fiber production₂SO₄The acid liquor and the alkali liquor generated by the recovery treatment are recycled and changed into Na2SO₄The waste is used as valuable, and simultaneously, the use of caustic soda is greatly reduced, thereby achieving the purpose of recycling the alkali liquor.

The invention is realized by the following technical scheme:

a treatment method for recycling alkali liquor comprises the following steps: 1) dissolving the sodium sulfate recovered from the viscose fiber production process into viscose fiber sodium sulfate waste liquid with the concentration of 5-20%; 2) carrying out multi-effect evaporation, concentration and crystallization on the sodium sulfate waste liquid, and adjusting the pH value after crystallization; 3) adding desalted water to remove impurities and filtering; 4) introducing the filtered sodium sulfate solution into a sodium sulfate flow channel of a bipolar membrane electrodialysis membrane group device, and then introducing desalted water into an acid flow channel and an alkali flow channel of the bipolar membrane electrodialysis membrane group device to finally prepare a sulfuric acid solution and a sodium hydroxide solution; 5) the sulfuric acid solution is returned to the step 2) for multi-effect evaporation concentration utilization, and the sodium hydroxide solution is filtered by a nanofiltration membrane and returned to the viscose production process for blending of the etiolation dissolving alkali, the primary leaching alkali solution and the secondary leaching alkali solution.

And (5) returning the residual sodium sulfate at the position where the sodium hydroxide solution is filtered by the nanofiltration membrane in the step 3) to the step for recycling treatment.

Sodium sulfate in the step 1) is directly dissolved by adopting desalted water.

The specific process of step 2) is as follows: the viscose waste liquid is crystallized after being concentrated and then is separated by a centrifuge, so as to obtain powdery solid containing sodium sulfate, zinc sulfate and sulfuric acid and concentrated sulfuric acid solution, the concentrated sulfuric acid solution is directly conveyed to an acid bath process in the viscose production process through a pipeline, and the powdery solid containing the sodium sulfate, the zinc sulfate and the dilute sulfuric acid is placed in a transfer tank for the next process.

And 3) adding desalted water into the transfer tank to dissolve the powdery solid to obtain a solution containing 5-30% of sodium sulfate, zinc sulfate and sulfuric acid.

And 3) sequentially carrying out primary filtration, secondary primary filtration, ion exchange filtration and pp microporous filtration fine filtration on the dissolved solution.

The filtering process in the step 3) comprises settling in a preparation tank, filtering in a primary bag filter, secondary settling in the preparation tank, secondary filtering in the bag filter, primary adsorption in a resin tower and secondary adsorption in the resin tower in sequence.

The concrete operation of the settling of the blending tank is as follows: and (3) adding alkali into the dissolved solution to neutralize to form a weakly alkaline environment, forming solid flocculent precipitate by impurity metal ions, carrying out precipitation, sedimentation and separation, discharging and recycling the physically precipitated precipitate by utilizing a sewage discharge outlet of a U-shaped sewage discharge device, and pumping out supernate to enter a post-filtering process.

The treatment method of the invention is used for the product Na produced by viscose fiber production₂SO₄The alkali liquor can be directly used for blending the etiolation dissolving alkali, the primary leaching alkali liquor and the secondary leaching alkali liquor in the viscose fiber production process, the use of caustic soda is greatly reduced, and the content of the caustic soda is changed into Na2SO₄The waste is used as a treasure, and the purpose of recycling the alkali liquor is achieved.

Compared with the prior art, the invention has the following advantages and beneficial effects:

the treatment method for recycling alkali liquor changes Na while greatly reducing the use of caustic soda₂SO4 is used as a fertilizer, and Na is reduced₂SO₄The waste amount of the alkali liquor reaches the purpose of recycling the alkali liquor.

Drawings

The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention. In the drawings:

FIG. 1 is a flow chart of a conventional viscose fiber production process;

FIG. 2 is a flow chart of the recycling of lye of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to examples and accompanying drawings, and the exemplary embodiments and descriptions thereof are only used for explaining the present invention and are not meant to limit the present invention.

Example 1

The invention relates to a treatment method for recycling alkali liquor, which comprises the following steps: 1) dissolving the sodium sulfate recovered from the viscose fiber production process into viscose fiber sodium sulfate waste liquid with the concentration of 5-20% by using desalted water; 2) carrying out multi-effect evaporation, concentration and crystallization on the sodium sulfate waste liquid, carrying out pH adjustment after crystallization, separating by a centrifuge to obtain powdery solid containing sodium sulfate, zinc sulfate and sulfuric acid and concentrated sulfuric acid solution, directly conveying the concentrated sulfuric acid solution to an acid bath process in the viscose production process through a pipeline, and placing the powdery solid containing the sodium sulfate, the zinc sulfate and dilute sulfuric acid in a transfer tank; 3) adding desalted water into the transfer tank to dissolve the powdery solid to obtain a solution containing 5% -30% of sodium sulfate, zinc sulfate and sulfuric acid, and sequentially performing primary filtration, secondary primary filtration, ion exchange filtration and pp microporous filtration fine filtration on the solution through settling of a preparation tank, filtration of a primary bag filter, secondary settling of the preparation tank, secondary filtration of the bag filter, primary adsorption of a resin tower and secondary adsorption of the resin tower; 4) introducing the filtered sodium sulfate solution into a sodium sulfate flow channel of a bipolar membrane electrodialysis membrane group device, and then introducing desalted water into an acid flow channel and an alkali flow channel of the bipolar membrane electrodialysis membrane group device to finally prepare a sulfuric acid solution and a sodium hydroxide solution with the concentration of 4-9%; 5) the sulfuric acid solution is returned to the step 2) for multi-effect evaporation concentration utilization, and the sodium hydroxide solution is filtered by a nanofiltration membrane and returned to the viscose production process for blending of the etiolation dissolving alkali, the primary leaching alkali solution and the secondary leaching alkali solution.

As shown in fig. 1, which is a flow chart of the existing viscose fiber production process, it can be seen that a large amount of caustic soda needs to be added to prepare alkali liquor in the production process, the usage amount of the caustic soda is large, and a large amount of sodium sulfate generated at the end of the process is wasted; fig. 2 shows the process of recycling the sodium sulfate generated at the end of the process by using the method of the present invention, and as can be seen from the flow chart in fig. 2, the sodium sulfate can be treated to a certain extent to generate an alkali solution and an acid solution, and the alkali solution can be returned to the viscose production process for blending the xanthation dissolved alkali solution, the primary-leaching alkali solution and the secondary-leaching alkali solution, so as to reduce the use of caustic soda, change waste sodium sulfate into valuables, realize the recycling of the alkali solution, greatly save the use amount of caustic soda in the whole process flow, and reduce the production cost.

The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.