Sodium-potassium ratio adjusting device of device for recovering mixed alkali from indigo products

Abstract

The invention relates to a device for recovering mixed alkali from indigo products. The device comprises a filter pressing recovery device and a washing water recovery device and is characterized in that a concentrating device is connected with a water outlet of an indigo aftertreatment filter press and a sodium-potassium ratio adjusting device respectively; the sodium-potassium ratio adjusting device is connected with a dehydration device; the dehydration device is connected to an indigo oxidation reactor; a water inlet of a washing alkaline water tank is communicated with the water outlet of the indigo aftertreatment filter press; a water outlet of the washing alkaline water tank is communicated with a water inlet of a suspended matter filtration alkaline water tank via a suspended matter filter; a water outlet of the suspended matter filtration alkaline water tank is communicated with a water inlet of an organic matter filtration alkaline water tank via an organic matter filter; a water outlet of the organic matter filtration alkaline water tank is communicated with a cooling alkaline water tank via a cooling tower; and the cooling alkaline water tank is connected to the indigo oxidation reactor. In combination with the requirements of an indigo oxidation process, the filter pressing filtrate is concentrated and the sodium-potassium ratio is adjusted to be reused in the indigo oxidation process, the low-concentration mixed alkali liquor after filter pressing and washing is collected and indiscriminately used as the water for washing and the water for diluting alkali fused materials and full recovery and surplus utilization of low-concentration mixed alkali are achieved through recovery and indiscriminate use, thus achieving the aims of reducing emission and reducing the consumption of fresh tap water.

Description

[0001] This application is a divisional application of the patent name: a device for recovering mixed alkali from indigo products, the application date is 2013-11-6, and the patent application number is 201310543782.9. technical field [0002] The invention belongs to a device for recovering raw materials for indigo production, in particular to a device for recovering mixed lye in the post-treatment washing process of vat dyes such as indigo. Background technique [0003] Indigo is an environmentally friendly vat dye with a long history, which is widely used in the dyeing of cotton fabrics, especially the warp yarns of indigo denim products. [0004] The current industrial production is to prepare indigo through the oxidation of 3-indoxyl salt. The reaction process includes a certain amount of aniline acetate, sodium amide, and a mixed alkali of sodium hydroxide and potassium hydroxide at 220~250°C. Reaction to obtain 20-30% alkali melt of 3-indoxyl salt, dissolve the alkali...

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Problems solved by technology

According to tracking statistics and analysis, during the post-treatment and washing process of indigo, the filter cake washing causes a large amount of alkali loss, and a large amount of tap water is required to dilute and wash the material. After the lost alkali enters the sewage treatment device, a large amount of acid is required. For neutralization, the treatment cost and production cost are high, and the formed inorganic salt is difficult to biochemically treat, which wastes alkali resources and causes large environmental pollution

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