A Study of the Reaction Rates Between Silica and Other Oxides at Various Temperatures. Part III. Reaction Rates in Binary and Ternary Mixtures Additional to those Described in Parts I and II
JSGT 1953 V37 T168-T181
The reaction rates of silica with lithia, potash and lead oxide have been investigated in binary mixtures and in ternary mixtures consisting of silica withpairs of the alkalis and with pairs of oxides consisting of an alkali oxide with the oxides of lead, calcium, barium, zinc, titanium and zirconium, respectively. The effects of small quantities of ferric oxide and titanium dioxide on the reaction rates in a silica–lime–soda mixture have also been studied. The procedure adopted in the firing and in controlling the temperature was the same as that previously used and explained in Part I, and the extent to which the reaction had occurred was determined by the x-ray-diffraction technique, also described in Part I. In mixtures containing lead oxide the reaction products were also examined microscopically. The results obtained show that: (1) The alkali-metal oxides, introduced as carbonates arranged in decreasing rate of reaction with silica can be placed in order as follows: (a) K2O, Na2O and Li2O when present in molecularly equivalent quantities; (b) Li2O, Na2O and K2O when introduced in equal quantities weight for weight. This applies also to ternary mixtures containing one of these oxides when that oxide is replaced partly or completely by one of the other alkali oxides. (2) Lead oxide reacts with silica at a lower rate than any of the alkali-metal oxides when present in equivalent amounts, but at a higher rate than B2O3, BaO, MnO, CaO or MgO. (3) The introduction of small amounts of soda or potash in replacement of part of the lead oxide in a silica–lead oxide mixture increases the rate of reaction very considerably. (4) The oxides arranged in order of decreasing rate of reaction with silica can be placed as follows: K2O, Na2O, Li2O, PbO, B2O3, BaO, CaO, ZnO, MgO, TiO2, Al2O3 and ZrO2. (5) The addition of a small amount of either ferric oxide or titanium dioxide, as a replacement
Abd-El-Moneim Abou-El-Azm
