The invention discloses a method and device for producing a 
chromium tanning agent by using oxidized waste liquid obtained from S 
wax production. The method comprises the steps of carrying out acidification and two-stage oxidation on raw materials, namely lignite 
wax, 
sodium bichromate, 
chromic anhydride (
chromium trioxide, CrO3) and 
sulfuric acid, so as to obtain the oxidized waste liquid; treating the oxidized waste liquid by using glucose serving as a 
reducing agent in a manner that glucose cooperates with 
sodium bichromate, so as to obtain a 
chromium tanning solution; 
drying and 
dewatering the chromium tanning solution, thereby obtaining the chromium tanning agent. The device comprises an oxidized waste 
liquid storage tank, an oxidized liquid reduction device, a chromium tanning agent 
recovery device, a high-position liquid supplying device and a supporting liquid distribution device. According to the method, the chromium tanning agent (alkaline 
chromic sulfate-chromium 
powder tanning agent) is prepared through reducing the chromium-containing oxidized waste liquid, formed during the production of S 
wax from lignite wax, by using glucose which cooperates with 
sodium bichromate, and tanned leather is plump, soft and elastic. According to the method and the device, the process is simple and energy-saving, the consumption of 
sulfuric acid and glucose is low, and the device is easy to implement, so that the large-scale, continuous and automated production can be realized.