| 摘要 |
<p>PURPOSE:To provide a method for removing unnecessary material in processing liquid by adding fine particles having adsorptivity and a filter aid to the processing liquid, circulating it through filter cloth to form cakes on the filter cloth and filtering the processing liquid. CONSTITUTION:Processing liquid to which potassium permanganate to activate oil contained as unnecessary material, activated carbon and diatomaceous earth are added is agitated in an agitation tank 10 to adsorb the activated oil contained as unnecessary material on the activated carbon and is fed to a filter 20 by a pump 11. At first, the filtrate is again returned to the agitation tank 10 through a circulating pipe 15 by a selector valve 14 to circulate it between the agitation tank 10 and a filter chamber 21 for required time, causing cakes 2 of the diatomaceous earth and activated carbon dispersed on the filter cloth 24 to be formed. The processing liquid 1 is filtered under pressure through the filter cloth 24 on which the cakes 2 are formed to adsorb and leave the oil on the activated carbon. The filtrate including caprolactam is recovered by the selector value 14 and the unnecessary material is surely removed.</p> |
