Resource utilization method of waste alkali liquid of viscose

Abstract

The invention provides a resource utilization method of waste alkali liquid of viscose. The method mainly comprises the steps of high recovery of alkali liquid, high recovery of hemicelluloses and preparation of xylose. The method concretely comprises the following steps: recovering part of alkali in the waste alkali liquid of the viscose by adopting a nanofiltration process, and then recovering the rest alkali in the waste alkali liquid by adopting an electrodialysis reversal (EDR) process; then, hydrolyzing the dealkalized waste alkali liquid under the acidic condition, and then carrying outdeacidifying treatment and desalting treatment on hydrolysate by adopting an ED process so as to obtain a xylose solution. The resource utilization method has the actual advantages that 1, the methodis reasonable in combination and adopts nanofiltration and EDR so as to realize segmented efficient recovery of hemicellulose and alkali; after the EDR technique is adopted, the problems absorption and pollution of the hemicelluloses to a membrane are effectively solved in a long-term running process, so that a high alkali liquid recovery rate is realized; the ED technique is used for carrying out the deacidifying treatment and the desalting treatment on the hemicellulose hydrolysate, so that a high hemicellulose hydrolysate xylose recovery rate is realized; 2, the recovered alkali liquid canbe used for a viscose fiber pulp dissolution process; the separated hemicellulose can be used as a new raw material of the xylose.

Description

technical field [0001] The invention relates to the field of waste water recycling, in particular to a method for recycling waste lye from viscose fibers. Background technique [0002] First of all, the raw materials of viscose fiber are mostly obtained from wood, cotton linters, bamboo, reed, bagasse, etc. Raw materials such as wood pulp and paper pulp contain not only cellulose, but also a certain amount of hemicellulose. In the actual production process, after the raw materials are pulverized, they are alkalized and impregnated with a 200g / L NaOH solution. At this time, the cellulose in the raw material cannot be dissolved due to the strong intramolecular and intermolecular hydrogen bonds, while the hemicellulose is more soluble in the lye. After pressing, ultrafiltration and other operations, the alkali-containing solution of hemicellulose can be obtained. In the production process of viscose fiber, if the concentration of hemicellulose is high, it will have an extrem...

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Problems solved by technology

[0005] The purpose of the present invention is to solve the problems of low alkali recovery rate and low xylose recovery rate occurring in the prior art. The present invention aims at the above problems and provides a method for resource utilization of viscose fiber waste lye: 1. Adopt nanofiltration to Part of the alkali in the waste lye is recovered, and then EDR (frequent electrode reversal electrodialysis, principle see figure 1 ) to carry out further alkali recovery and frequently change the polarity of electrodialysis electrodes, which can effectively solve the problem of hemicellulose fouling, thereby achieving high alkali recovery and high recovery of hemicellulose; 2. Due to the thorough alkali recovery in the previous stage, the hydrolysis For the part, the amount of medicine added is small, the hydrolysis is thorough, and then the hydrolyzate is desalted and deacidified by ED technology. Since sugars such as xylose are not charged, they can be efficiently separated from salt and acid in the ED system. Xylose has high recovery rate

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