RU2738728C1 - Method for recycling of leather chips as used sorbent - Google Patents

Abstract

FIELD: biotechnology.

SUBSTANCE: invention represents a method for recycling of leather chips as a spent sorbent of a confectionary enterprise, used in production of glue as main component of spent sorbent—leather chips with size from 0.5 to 5 mm with preliminary reliming by lime mixture from 10 to 14 g/l and calcined soda from 0.2 to 0.6 g/l for 10–12 hours, washing wastes with running water, neutralization with ammonium sulphate and sulfuric acid, repeated washing and thermal treatment at temperature 58 °C for 6 hours.

EFFECT: invention enables to remove alkali completely from the raw material using the lime mixture from 10 to 12 g/l and calcined soda from 0.2 to 0.3 g/l at the reliming stage, and also makes it possible to use spent sorbent as main component in preparation of adhesive composition ground to size from 0.5 to 5 mm.

1 cl, 4 ex

Description

The invention relates to a technology for the production of an adhesive composition and can be used for the disposal of leather shavings as a waste sorbent after purification of waste water from confectionery enterprises.

A known method of manufacturing (see A.S. N 262300, publ. 26.01.70) skin glue, which consists in heat treatment and flow of leather shavings. The technological process consists of the stages described below. The boiler is fed with leather shavings and 45% of water (the amount of water supplied to the boiler is determined as a percentage of the initial weight of the raw material). Cooking is carried out at a temperature of 90 ° C. Then, after every hour of cooking, the broth is drained. After the first hour of cooking, 10% is drained, after the second - sixth hour - 20% each. After the seventh hour of cooking, drain all the broth, pour 30% water into the kettle and heat for one hour at a temperature of 100 ºС. Then all the broth is poured into one settling tank. The resulting composition is stirred with a stirrer. Two hours after the start of cooking, they begin to remove the fat in the boiler with the mixer turned off until the end of cooking. At the same time, remove the fat from the broth. After pumping all the broth into the collector and settling for an hour, the fat is additionally removed. Then the broth is filtered, separated, clarified, dried.

However, the disadvantage of this method is the long duration of cooking and high energy consumption, as well as the receipt of a black adhesive composition that does not lend itself to bleaching.

Also known is a method of obtaining (Inventor's certificate SU N 450255, 03/11/1975) glue from waste chrome tanned leather. The method consists in the fact that the cuttings are soaked in a 5% sodium hydroxide solution for 4 to 6 days (after 2 to 3 days the solution is drained and replaced with a new one), washed with water, neutralized with a weak 1% solution of magnesium chloride or ammonium , washed again and boiled with the addition of 1 to 2% to the weight of the scraps of magnesium oxide for one hour in an autoclave. Then the glue broth is drained and the boiling is continued with clean water and bleached with hydrosulfite. The resulting adhesive composition has a viscosity at 30 ° C from 4 to 4.5 Pa⋅s.

The disadvantage of this method is the stage of de-ash removal, since the proposed technological process does not provide complete removal of alkalis from raw materials that adversely affect the cooking process and the quality of the resulting glue.

The technical objective of the invention is to modernize the de-ash removal stage and expand the possibilities of using leather shavings as a main component as a spent sorbent.

The technical result achieved by the present invention is the complete removal of alkalis from raw materials used at the stage of de-ash removal of a mixture of lime from 10 to 12 g / l and soda ash from 0.2 to 0.3 g / l, as well as the possibility of using the spent sorbent as the main component in the preparation of an adhesive composition, crushed to a particle size of 0.5 to 5 mm.

In the experiment on the preparation of the adhesive composition, a waste sorbent from a confectionery enterprise was used.

An example of the implementation of the method.

Example 1. 50 g of raw materials, crushed to a particle size of 0.5 mm, are kept in a flask at a temperature of 25 ° C in a solution of a mixture of lime 10 g / l and soda ash 0.2 g / l for 10 hours.

Next, we rinse the waste with running water, neutralize with ammonium sulfate and sulfuric acid and rinse again.

Then the resulting material is subjected to heat treatment at a temperature of 58 ° C for 6 hours and thereby obtaining an adhesive composition.

Example 2. 50 g of raw materials, crushed to a particle size of 2 mm, are kept in a flask at a temperature of 27 ° C in a solution of a mixture of lime 11 g / l and soda ash 0.2 g / l for 11 hours.

Next, we rinse the waste with running water, neutralize with ammonium sulfate and sulfuric acid and rinse again.

Then the resulting material is subjected to heat treatment at a temperature of 58 ° C for 6 hours and we get an adhesive composition.

Example 3. 50 g of raw materials, crushed to a particle size of 3.5 mm, are kept in a flask at a temperature of 28 ° C in a solution of a mixture of lime 12 g / l and soda ash 0.3 g / l for 12 hours.

Next, we rinse the waste with running water, neutralize with ammonium sulfate and sulfuric acid and rinse again.

Then the resulting material is subjected to heat treatment at a temperature of 59 ° C for 8 hours and thereby obtaining an adhesive composition.

Example 4. 50 g of raw materials, crushed to a particle size of 5 mm, are kept in a flask at a temperature of 30 ° C in a solution of a mixture of lime 12 g / l and soda ash 0.3 g / l for 12 hours.

Next, we rinse the waste with running water, neutralize with ammonium sulfate and sulfuric acid and rinse again.

Then the resulting material is subjected to heat treatment at a temperature of 60 ° C for 8 hours and thereby obtaining an adhesive composition.

Carrying out the above considered experiments allows you to obtain an adhesive composition with a spent sorbent as the main component, corresponding to GOST 3252 - 80 without generating waste.

The proposed method for producing an adhesive composition in comparison with an analogue allows:

- to reduce the duration of cooking and the energy consumption of the process;

- modernize the stage of de-ash removal until complete removal of alkalis from raw materials, which adversely affect the cooking process and the quality of the resulting adhesive composition;

- to use as the main component not only skin trimming, but also leather shavings as a spent sorbent for purification of waste water from confectionery enterprises with a size of 0.5 to 5 mm without generating secondary waste;

- to reduce the negative impact of leather waste on the environment.

Claims (1)

A method for utilizing leather shavings as a spent sorbent of a confectionery enterprise, providing for the use in the production of glue as the main component of a spent sorbent - leather shavings with a size of 0.5 to 5 mm with preliminary de-ash treatment with a mixture of lime from 10 to 14 g / l and soda ash from 0, 2 to 0.6 g / l for 10-12 hours, washing the waste with running water, neutralization with ammonium sulfate and sulfuric acid, repeated washing and heat treatment at a temperature of 58 ° C for 6 hours.