Sodium hydroxide silicate production

Water glass. A familiar and useful silicate is that known as water glass. Although the commercial product consists of a rather complex mixture of silicates, water glass is commonly represented by the formula for the normal sodium salt of metasilicic acid, Na2Si03. This material is produced by heating sand with sodium hydroxide under pressure... 

To obtain the 7(a)-isomer of 7,17-dimethyltestosterone the crystalline mixture of the 7 stereoisomers of 7,17-dimethyltestosterone was refluxed in tertiary butyl alcohol with recrystallized chloranil under nitrogen. The reaction mixture was concentrated under a fast stream of nitrogen, diluted with methylene chloride and the solution washed with dilute sodium hydroxide, water and then dried, filtered and the solvent removed. The residue, was combined with the product from an identical run and chromatographed through a magnesium silicate column developed with solvent of the following composition and order two each of hexane hydrocarbons (Skellysolve B), hexanes plus 4% acetone, hexanes plus 8% acetone, hexanes plus 12% acetone, hexanes plus 14% acetone, hexanes plus 16% acetone, hexanes plus 18% acetone, hexanes plus 20% acetone, hexanes plus 24% acetone, hexanes plus 28% acetone, and two of acetone. 

The primary reaction of any pozzolanic material is an attack on the SiOj or AljOj-SiOj framework by OH ions. It may be supposed that the OH ions attach themselves to silicon and other network-forming atoms, with consequent breaking of bonds between the latter and oxygen atoms. After this has occurred several times, the silicate or other oxy anion is detached from the framework. It may either remain in situ or pass into the solution. The charges of those that remain are balanced, partly by H, and partly by metal cations. Since a cement pore solution is essentially one of potassium and sodium hydroxides, the immediate product is likely to be an amorphous material with and Na as the dominant cations, but the more abundant supply of Ca and the lower solubility of C-S-H and hydrated calcium aluminate or silicoaluminate phases will ensure that this is only an intermediate product. Its presence is indicated by the relatively high potassium contents observed in or near to the reacting pfa particles. 

Reaction of Silicon on Solutions of Alkali Hydroxides. This method is based on the reaction of a concentrated solution of sodium hydroxide on powdered silicon or ferrosilicon, where hydrogen and a solution of sodium silicate are the products of the reaction ... 

Lundquist (L17) proposed a leaching scheme in which silica and some silicate minerals are removed by sodium hydroxide solution from very-low-grade manganese ores and manganese flotation concentrates, leaving a product with an upgraded manganese content. Separation of the residue by filtration was carried out at 60-70°C. The spent leach liquor was... 

Unlike X type molecular sieve, the Si/Al ratio of Y type molecular sieve normally falls in the range 1.5-3. The laboratory synthetic method introduced here was developed by D.M. Ginter, A.T. Bell, and C.J. Radke (Ref. [125]). Deionized water, sodium aluminate (Na/Al=1.27, 6.1% H20), sodium hydroxide pellets, and sodium silicate solution (28.7% Si02, 8.9% Na20) were used to prepare the reaction gel with a composition of 4.62 Na20 A1203 10 Si02 180 H20. The detailed procedure for the preparation of 32 g of dry product is described below ... 

MCM-22(P) was synthesized in the following way 0.23 g of sodium silicate and 0.81 g of sodium hydroxide were dissolved in 103.45 g of distilled water, after which 6.35 g of hcxamcthylcneimine and 7.86 g of silica Aerosil 200 were added successively. The mixture was stirred for 30 min at room temperature followed by a 11-day reaction in a stirred Teflon-lined autoclave at 135 °C. Swelling of the solid product was carried out by refluxing mixture of 27 g of the slurry with 105 g of a 29 wt. % aqueous hcxadecyltrimethylammonium bromide solution and 33 g of a 40 wt. % aqueous solution of tctrapropylammonium hydroxide at 80 °C for 16 h. Calcination was performed at 540 °C [15],... 

Sodium silicates are made by fusing (melting) sand (silicon dioxide) and soda ash (sodium carbonate) or sodium hydroxide in a gas-fired open hearth furnace, somewhat similar to the furnaces used in the manufacture of steel. The products of this reaction are lumps of sodium silicate that are broken apart and dissolved in a stream of hot steam. The proportions of sand and soda ash used, the temperature of the reaction, and the amount of water that remains in the final product all determine the physical properties of the final product. 

The common method for preparing a colloidal solution of hydrous ferric oxide, for example, has been to hydrolyze ferric chloride in solution by heat, and remove the hydrochloric acid by dialysis. Colloidal silica can be made in a similar way, that is, by dialyzing a solution of sodium silicate. One hydrolysis product—hydrochloric acid or sodium hydroxide—can pass through the membrane used for dialysis, whereas the colloidal particles of hydrous oxide cannot. The process is rather tedious and takes hours or even days. A much simpler method is to take out the acid or alkali with one of the solid ion exchangers or acid absorbers used in water purification. ... 

The soluble silicates are not designated as hazardous substances under Section 311 of the Federal Water Pollution Control Act, relating to discharges or spills into navigable waters (46). However, some commercial sodium orthosilicate products are actually physical blends of sodium hydroxide and sodium metasilicate particles. Such mixtures are EPA hazardous substances by virtue of their sodium hydroxide content, and their reportable quantity is the equivalent of 1,000 lbs of sodium hydroxide (47). 

If a highly alkaline sodium silicate waste is classified as a hazardous waste under RCRA, it is also a hazardous substance under the Comprehensive Environmental Response, Compensation and Liability Act of 1980 (CERCLA or Superfund Act), The law s reporting requirements would apply to any release into the environment. This is also true for the previously mentioned sodium orthosilicate products which are EPA hazardous substances, since they are physical mixtures containing sodium hydroxide. For sodium hydroxide the reportable quantity remains... 

The year 1941 was the turning point toward commercial silica sol production methods. Bird [10], at Nalco, found that low-molecular-weight silicic acids could be prepared by ion exchange. If a small amount of sodium hydroxide was added to these materials, particles were formed. These materials could then be concentrated with conventional evaporator techniques to about 27.5% silica. Nalco... 

Crystalline aluminosilicates, composed of silica (Si02) and alumina (A1203), in various proportions plus metallic oxides. Produced by hydrothermal treatment of a solid aluminosilicate or of a gel obtained by the reaction of sodium hydroxide, alumina hydrate and sodium silicate. The initially obtained product, or a naturally occurring analog, may be partially ion-exchanged to introduce other cations. Specific zeolites are identified by notations indicating crystal structure and predominant cation, e. g., KA, CaX, NaY. 

The alkaline activators include sodium or potassium hydroxide, silicate, and carbonate. The rate of setting and hardening of alkali-activated binders and the quality and quantity of the resulting reaction products depend on a variety of factors, including the quality of the starting aluminosilicate, the quality and amount of alkaline activator, and the temperature of reaction. 

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