Process and system for recycling and decoloring denim mercerizing alkali and penetrant

Abstract

The invention discloses a process and system for recycling and decoloring denim mercerizing alkali and penetrant. The process includes the steps that denim mercerizing alkali liquor is placed in a first precipitation tank; the liquor on the upper portion enters a conveying pipeline through a flow pump after precipitation, meanwhile, a metering pump pumps a decolorising agent into the liquor in the conveying pipeline, and then the decolorising agent and the liquor are conveyed to an evaporation concentrator together; the decolorising agent and the liquor enter a second precipitation tank after being evaporated and concentrated; supernatant liquor obtained after precipitation is conveyed to a production line directly; solid substances in precipitation liquor on the lower portion are separated and conveyed to a waste solid storage tank after the precipitation liquor on the lower portion is treated through a centrifugal machine, and clear liquor returns the first precipitation tank and is conveyed backed to the production line. The system comprises the first precipitation tank, the flow pump, the metering pump, a decolorising agent box, the evaporation concentrator and the second precipitation tank. The first precipitation tank, the flow pump, the evaporation concentrator and the second precipitation tank are connected directly through pipelines, and the decolorising agent box is connected to the metering pump below the pipeline where the flow pump and the evaporation concentrator are connected. The process for recycling and decoloring the denim mercerizing alkali and penetrant is simple, the useful alkali and penetrant are recycled, and production cost is greatly reduced.

Description

[0001] technical field [0002] The invention relates to a process and method for co-recovering lye decolorization and penetrant, especially a process and system for recovering lye and penetrant and decolorizing denim after mercerizing in the printing and dyeing industry, which belongs to resource recycling and utilization Energy saving and emission reduction technology field. Background technique [0003] The silk light source of cotton fabric was discovered by British chemist Messer in 1844. It was not officially applied to the printing and dyeing industry until the end of the 19th century, becoming an important process in the dyeing and finishing of cotton textiles. It plays an extremely important role in improving the intrinsic quality and appearance quality of cotton fabric products. The so-called mercerization refers to the cotton textiles under a certain tension state, with the help of concentrated caustic soda, to maintain the required size and obtain a silky luste...

AI Technical Summary

Problems solved by technology

[0005] 1. The mercerizing process of denim is to carry out mercerizing immediately after singeing, and in the mercerizing process, in order to reduce the surface tension of the lye, so that the lye can quickly penetrate into the fiber to produce a mercerizing effect, a certain amount of lye must be added to the lye amount of penetrant, so that the light lye after mercerizing is easy to foam

[0006] 2. The impurities brought by the fabric during mercerizing will fall into the light lye (such as plush, short fiber, slurry, etc.), a large amount of impurities and slurry will affect the recycling of the light lye, and also cause COD (chemical Oxygen demand), BOD (biochemical oxygen demand or biochemical oxygen demand), SS (suspended solids in water quality), etc.

[0007] 3. Due to the weak chroma during sizing and dyeing, the light lye has a deep chroma after mercerizing, which seriously affects the recovery and application of lye

Therefore, the "concentrated" alkali decolorized in the above-mentioned way affects the subsequent recycling, and the operability of practical application is not strong

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