| Résumé : |
Subsequent to the closure of Industrial Extracts Ltd (manufacturers of "Myrtan" tanning extract) several friends suggested to me that a knowledge of the could be of interest to other chemists in the industry.
The company was then confronted by an acute problem. The 1950s had seen intense competition between mimosa and quebracho inteerests which forced down prices to a level where "Myrtan", with its handicaps of poor colour and solubility, could no longer continue to undersell its competition.
Fortunately, sales of "Myrtan" as a "mud thinner" in the drilling of oil wells were buoyant until a range of new thinners based on iron and chromium lignosulphonates was introduced which, although expensive, showed vastly improved performance. This left the company with no option but to try to recover its market in the leather industry and in 1960 work started with this in view.
At the time, the process was operated in the following way. Logs of Eucalyptus redunca and E. accadens were reduced to a rough sawdust in conventional hoggers and extraction was carried out in two sets of stainless steel vessels, each holding about five tons of wood, by a normal counter-current system. The vessels were air-tight so that liquors could be presse forward by the application of steam pressure at the tail of the system. The rate of extraction was such that, with the tail of the system at 100°C, the head liquor with about 5 % solubles ran off at about 65°C. The liquor was pumped straight to a three-stage evaporator, emerging at 200° Bk, and was then either spray-dried or finished as solid extract. The problems to be addressed were poor colour and poor solubility. |
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Short paper : some notes on the production of a tanning extract in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. N° 71 (Année 1987)
