ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Physicochemical study of beet-sugar-juice purification. VI. The liberation of calcium from calcium pectate by saturation with carbon dioxide

J. Vašátko, R. Kohn, and Z. Kohnová

Slovak Academy of Sciences, Bratislava

Abstract: cf. C.A. 51, 7745b. The reason for the increase of electrokinetic potential ζ of the particles in the defecation cake from the beet-sugar juice, clarified with lime and 'satd.' with CO₂, was studied. The theoretical conditions for setting free Ca from Ca pectate (I) by 'satn.' with CO₂ were proven experimentally. In the pure system with distd. H₂O or 15% sucrose soln. Ca bound on the carboxy groups of pectic acid can be set free and form ionized carboxy groups by 'satn.' with CO₂ even in the presence of NaOH. There is a double reaction between I and alk. carbonate which is similar to the reaction occurring in the 2nd 'satn.' At certain excessive effective alky. and with 'over-satn.' of muddy 1st juice to pH of 2nd 'satn.,' there is the same double reaction which results in the formation of Ca salts making up the defecation cake.

Full paper in Portable Document Format: 118a467.pdf (in Slovak)

Chemical Papers 11 (8) 467–477 (1957)