Chemical apparatus and process disinfecting – deodorizing – preser – Chemical reactor – Including heat exchanger for reaction chamber or reactants...
Patent
1988-01-28
1991-08-06
Lacey, David L.
Chemical apparatus and process disinfecting, deodorizing, preser
Chemical reactor
Including heat exchanger for reaction chamber or reactants...
422209, 422224, 34 63, 432107, B01J 810
Patent
active
050376209
ABSTRACT:
A new anhydrous sodium dichromate in flakes, Na.sub.2 Cr.sub.2 O.sub.7, m.p. 356.degree. C. (dec. 400.degree. C.) is described, characterized in that it comes in flakes with an area of approx. 1 cm.sup.2, thickness 0.5 mm and apparent specific gravity 1.10 (absolute 2.748) at 25.degree. C; it is not deliquescent, nor does it become powdery. It is prepared from dihydrate sodium dichromate or aqueous solutions thereof using a new process in two stages, namely a) evaporation-melting of the dihydrate salt or concentrated aqueous solution at a strictly controlled temperature of around 380.degree. C. and no higher, and b) flaking of the melted mass obtained thereby, as it is being rapidly cooled to 150.degree.-160.degree. C. The apparatus for carrying out the process is also disclosed; the apparatus includes a dehydrator-melter oven, a flaker rotating at 10-20 revs per minute and a heat recovery system. The thermic contribution, respectively positive and negative in the two stages, is provided by a particular eutectic mixture of melted salts, which melts at 139.degree. C. The mixture is composed of KNO.sub.3 52.2%, NaNO.sub.3 7.0%, NaNO.sub.2 39.4%, K.sub.2 Cr.sub.2 O.sub.7 1.4%.
REFERENCES:
patent: 3544522 (1970-12-01), Hahn
Kirk-Othmer, Encyclopedia of Chemical Technology (1978 ed.), vol. 6, pp. 92-96.
"Technology of Chromium Compounds", 1967, pp. 330-331; T. D. Auerbach and P. G. Pavlov.
"Fundamentals of Crystallization Technology of Melts", M. Khimiya 1975, pp. 131-132, FIG. III-27; N. I. Galperin et al.
Beisner William H.
Lacey David L.
Luigi Stoppani S.p.A.
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