Process for recovering proteins and chromium from chrome-tanning waste
OwnerGiuliano Guardiniinventor
Life of this patent
Estimating the term…
Abstract
Waste products from the chrome-tanning of hides are washed and then chopped in water, with subsequent hydrolyzation at a pH of at least 10.5 and at boiling or near-boiling temperature. The resulting suspension is filtered to yield a polypeptide solution and a cake of solids consisting essentially of chromium hydroxide. The solution is neutralized, dehydrated, cooled and filtered to provide a virtually chromium-free proteinaceous substance usable as plant or animal feed; the solids are washed, filtered and acidified to provide chromium sulfate suitable for reutilization in tanning.
Claims14
A process for the treatment of chrome-tanning waste products to recover proteins and chromium therefrom, comprising the steps of:
- (a) comminuting the waste products to be treated;
- (b) hydrolyzing the comminuted products at elevated alkalinity and temperature to produce a resulting suspension of solids in a polypeptide solution, said solids consisting essentially of chromium hydroxide, the hydrolysis being carried out with NaOH added in a proportion ranging between substantially 4% and 8% by weight of the products of step (a) with a minor proportion of an additive selected from the group which consists of Ca(OH).sub.2 and MgO;
- (c) filtering said suspension to separate said solids from said solution;
- (d) neutralizing and purifying said solution to provide a proteinaceous nutriment substantially free from chromium;
- and
- (e) separately purifying said solids.
Dependencies are inferred from the claim text.