The invention discloses a salt-free high-chrome-absorption chrome tanning method for
animal skin and application of the salt-free high-chrome-absorption chrome tanning method. The salt-free high-chrome-absorption chrome tanning method is characterized by comprising the following steps of treating pretreated
animal skin by using aromatic
sulfonic acid or a low-molecular polycondensate thereof; regulating the pH value of the
animal skin to 4.0-6.5 under the condition that no neutral salts such as
sodium chloride and
sodium sulfate are used; and carrying out chrome tanning under a relatively high initial pH value condition to realize salt-free high-chrome-absorption tanning. By using the salt-free high-chrome-absorption chrome tanning method, the problem that the quality and performances of leather or fur are influenced because the
skin possibly has the acid expansion phenomenon under salt-free and acidic tanning conditions, the combination of chrome and the surface of the
skin are excessively fast during the tanning, and the chrome cannot permeate the
skin easily under the relatively high initial pH value condition is solved; and compared with the conventional chrome tanning method, the chrome tanning method disclosed by the invention is advantaged in that the chrome tanning efficiency is remarkably increased, the consumption of chrome can be reduced by more than 30%, the
absorption rate of chrome is up to more than 98%, the concentration of chrome in chrome tanning
effluent is reduced to be less than 50mg / L, chrome in wet blue leather is more uniformly distributed, and the chrome tanning
effluent can be recycled many times. By using the salt-free high-chrome-absorption chrome tanning method, the
chlorine and chrome
pollution generated in the leather and fur preparation processes is remarkably reduced.