Improvements in or relating to the scouring of wool

摘要

Wool grease is recovered from alkaline wool scouring liquors containing an anionic detergent by adding to the liquor a minor proportion of a water-soluble ionizable salt which does not form an insoluble reaction product with the usual compounds found in spent wool scouring liquor, the salt comprising an alkali metal or ammonium salt of an organic acid of less than 3 carbon atoms or of a mineral acid, heating the liquor until its colour darkens and it gives a specified spot test, and then separating the wool grease from the liquor by centrifuging. The critical point is where the grease-water emulsion begins to break but has not actually broken, with no "salting out" of the soaps, detergents or proteins, and is determined by a spot test of the liquor on filter paper which shows an outside clear aqueous ring with a dark centre. The spent liquor, after the centrifuging, is suitable for further use in scouring wool without further addition of soda ash &c. the liquor being revivified by the added salt which acts as a builder. The preferred salt is sodium chloride. Other suitable salts comprise potassium and ammonium chloride, sodium, potassium and ammonium sulphates and nitrates, sodium thiocyanate, borax, ammonium dichromate and ammonium acetate. In the case of sodium chloride, it is added in an amount between 2 to 13 per cent., and preferably 4 to 6 per cent. of the total weight of the liquor. In the case of a salt other than sodium chloride, it is added in an amount equivalent in cationic effect to the amount of sodium chloride specified. The liquor is preferably heated to boiling or above but lower temperatures may be used.