Method for preparing multiple metallic ion leather tanning agents

Abstract

The invention discloses a method for preparing a plurality of metal ion leather tanning agents by utilizing chromium-containing and collagen solid wastes. Materials belonging to leather originally such as leather meal, leather bits and pieces, waste leather are used as raw materials for preparing chemical material which can be processed into leather; the chemical material is used in leather tanning and then is applied back to the leather; the chemical material has the best compatibility with the leather and can effectively form the self-closed recycle of materials. Namely, the chromium-containing and collagen solid wastes are used as a reducing agent instead of glucose, sulfur dioxide, etc., and ferrous sulfate is used as a supplementary reducing agent, so as to deoxidize sodium bichromate to prepare the leather tanning agents; chromium compounds in the solid wastes again become part of the metal ions which are used for preparing the tanning agents; collagen hydrolysate or oxidation products become filling materials in the tanning agents; the supplementary reducing agent becomes another metal ion in the tanning agents after being oxidized; the leather tanning agents containing a plurality of metal ions are prepared through the bridge link between sodium citrate and sodium tartrate.

Description

technical field

[0001] The invention relates to a preparation method of a leather tanning agent, in particular to a method for preparing a leather tanning agent with various metal ions from solid waste containing chromium and collagen. Background technique

[0002] China is a big country in leather production and consumption. Since most manufacturers still mainly use chrome tanning, a large amount of chrome-containing solid waste will be generated, such as chrome-containing leather shavings, leftovers from making leather products, and waste leather products. Wait. The matrix of the above-mentioned chromium-containing solid waste is animal skin collagen, and contains a large amount of chromium compounds, wherein more than 90% of collagen is contained, and about 7% of the chromium-containing compound is sodium alum. There are only about 300,000 tons of chromium-containing leather shavings produced in China every year. If these chromium-containing wastes are discarded, one wil...