THE MELTING RELATIONS OF POTASH FELDSPAR, SODA FELDSPAR, AND FLINT MIXTURES¹

Abstract

P.C.E. values of ternary mixtures of potash feldspar, soda feldspar, and flint were determined and results shown on a solid phase diagram. No eutectics were developed with either of the binary series of feldspar and flint. The soda feldspar-flint mixtures were more refractory than were those of the potash feldspar series. At least 20% flint variation with potash feldspar will show no change in P.C.E. values and a t least 10% with the soda feldspar showing the unreliability of P C.E. to indicate the amount of the quartz content.

Use of Soda Feldspar in Whiteware Bodies *

“…(C) Trial of Sanitary Ware Production: I n the second plant trial a t the sanitary porcelain pottery, a sufficient quantity of casting slip of bodies No. 1 and No. 4 was prepared to cast two toilet bowls of each body; the same procedure was followed as described for the previous trials.…”

“…The tests on the ware of the semivitreous bodies were (1) water absorption of the bisque, (2) resistance to crazing by thermal shock, (3) resistance to crazing in the autoclave, and (4) impact resistance.…”

“…I n making additions of electrolyte, the correct amount to obtain the required casting properties was determined by tests. As in the usual plant procedure, these consisted of (1) a "feel" test, (2) a test cast, and (3) a viscosity test. The hydrogen-ion concentration was also determined on the slip as cast, but its value did not govern the adjustment of electrolyte.…”

“…In determining which one of the three bodies tontaining the soda feldspar was the most promising compared with No. 1…”

“…4 with experimental glaze No. 1 and were fired with other ware in regular production. After firing, all four bowls were found to be in perfect shape with no indication of warpage or cracking.…”