Method for directly recycling vegetable tanning waste liquor

The invention discloses a method for directly recycling vegetable tanning waste liquor. The method includes the steps that after the pH of the vegetable tanning waste liquor is adjusted through acid substances, the vegetable tanning waste liquor is directly added into a drum with delimed softened naked leather, rotating processing is carried out for at least 60 minutes, then the system pH value is decreased through acid, rotating processing is carried out for at least 60 minutes, powdery tanning extract is added, rotating and stopping are alternately carried out till the naked leather is completely tanned, waste liquor is collected, and follow-up operation is carried out on the obtained vegetable-tanned leather according to a conventional heavy leather processing technology. By means of the method, the vegetable tanning waste liquor can be reused at least for five times. According to the method for directly recycling the vegetable tanning waste liquor, operation is easy, and the speed of combining the powdery tanning extract with collagen fibers can be decreased while the tanning extract permeating speed is increased, so that the vegetable tanning process is faster, more even and more mild, and meanwhile the phenomenon that surfaces are excessively tanned can be avoided. In addition, by means of the method, the use rate of the tanning extract can be obviously increased, and the use amount of neutral salt, the amount of the discharged vegetable tanning waste liquor and the waste liquor pollution load can be reduced.