Neutralization of Hide

(in technology), reduction of the acidity of leather after tanning with compounds of chromium, aluminum or zirconium, intended to fix the tanning substance with albumin and create favorable conditions for subsequent dyeing of the leather. Before neutralization, the hide is washed with warm water, and the excess acid is then neutralized with weak alkaline reagents (sodium bicarbonate and ammonium sulfate, sodium carbonate and ammonium sulfate). Leather tanned with compounds of zirconium is neutralized with hexamethylenetetramine or sodium sulfite. The waste products of neutralization are removed by subsequent rinsing.