The solution used contains a predetermined amount of a chromate dissolved in 37-38% H2SO4 so that the molar ratio H2SO4: chromate is 4-4.5:1 and the weight ratio of wax to be treated to CrO3 is 100:70 to 100:160 of the water (65-70%) is distilled off and returned after a 1-3 hr. interval of boiling under reflux (to utilize the remaining chromate better). By this method the spent solution has a nearly constant composition irrespective of the type of wax being refined (low CrO3 and H2SO4 contents) and can be utilized in the production of chrome-tanning solutions.
