Potassium Polysilicate

Both sodium and potassium polysilicates are used in formulations of these types, and it is critical that products containing two (or slightly more) molecules of silica to every one molecule of sodium oxide are obtained to ensure adequate long-term inhibitor effectiveness. 

Similarly, the high ratio lithium silicates of Her U.S. Pat. No. 2,668,149 or the potassium polysilicates of Wol-tersdorp, application Ser. No. 728,926, filed May 14,1968, now Defensive Publication 728,926, dated Jan. 7, 1969, can be employed as the binder provided the requirements as to molar ratio, particle size and amount of amorphous silica are followed. 

Synonyms Potassium metasilicate Potassium polysilicate Silicic acid, potassium salt... 

Potassium polysilicate. See Potassium silicate Potassium propionate... 

Very high strength gels have been made by Shoup from mixtures of potassium sili cate and colloidal silica as described under potassium polysilicate in Chapter 2, Refs. 97 and 98. Such compositions may have high binder strength in cases where the residual potassium salt is permissible. 

In 1981, Harris et al. systematically studied the state and distribution of polysilicate anions in potassium silicate solution through analyses of their 29Si-NMR spectra.[3] They found that the state and distribution of polysilicate anions in potassium silicate solution are similar to those in sodium silicate solutions. Figure 5.3 shows the state and distribution abundance (the number in parentheses indicates the relative abundance of the polymerized silicate with the assumption of 100 monomers.) of 18 types of polysilicate anions existing in potassium silicate solution with a concentration of... 

Figure 5.3 The state and distribution abundance of the polysilicate anions that exist in potassium silicate solution (0.63mot/L, K Si— 1.5 1.0)...

In addition, Harris s studies indicated that the polymerization state of the polysilicate anions in the potassium silicate solution is similar to that in the sodium silicate solution with the same silica concentration. The difference lies in their relative distribution abundance. 

Ethyl polysilicate. See Polydiethoxysiloxane Ethyl potassium carbonate Ethyl potassium xanthate Ethyl potassium xanthogenate. See Potassium ethyl xanthate Ethyl propanoate. See Ethyl propionate 1 -Ethyl-1 -propanol. See 3-Pentanol Ethyl 1-propene-1,2,3-tricarboxylate. See Ethyl aconitate, mixed esters Ethyl propenoate Ethyl 2-propenoate. See Ethyl acrylate Ethyl propionate... 

Because lithium silicates are so different in behavior from sodium and potassium silicates, lithium polysilicate is discussed separately. 

It has not generally been recognized that in the polysilicate system, the potassium ion behaves very differently from sodium. Although the coagulating effect of these ions is generally similar in most colloid systems and even in collloidal silica at pH 7-10, the potassium loses its coagulating effect at higher pH but sodium does not. (This is discussed in further detail in Chapter 4.)... 

These were apparently different from the previously reported crystalline sodium polysilicates, but had similar ion-exchange properties. Systems containing Li and K with different silica-alkali ratios were also studied. Crystalline silicates in the lithium system can be expected, but my experience with the potassium system indicated that insoluble polysilicates did not form under conditions w here the sodium compounds were obtained. 

Sodium polysilicate, rather than the more common 3.25 1 ratio of SiOziNaxO, was used because the latter is incompatible with the colloidal silica, causing gelling even before addification. Similar gelled bodies have been described by Shoup (Cahpter 2, Ref. 96), who found that potassium silicate of any ratio is compatible with concentrated colloidal silica. 

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