Balanced Alkali

Balanced Alkali is a proprietary chemical of Eastman Kodak, and until recently it was known as Kodalk . Balanced Alkali is more alkaline than borax and more easily soluble, but less alkaline than carbonate. As Balanced Alkali contains no free carbonate, there is no danger of carbonic gas bubbles being formed when an acid stop bath is used (see the next section, Moderate Alkalis). Balanced Alkali can be substituted for carbonate (Conversion Tables Alkali Substitutions), and for almost all purposes it is identical to sodium metaborate. 

A substitution for Balanced Alkali can be made by mixing sodium hydroxide with borax, decahydrate (Appendix 3 Pharmacopoeia Balanced Alkali). 

Uses An alkali used as an accelerator in developers of intermediate activity between that of carbonate and borax. Developers containing Balanced Alkali usually have a pH range of 9 0 to 10.0, and the concentration varies from 2 to 50g/L. 

A second advantage is that Balanced Alkali does not release a gas when added to an acid rinse or an acid fixing bath hence it minimizes blistering. ... 

Substitutions Balanced Alkali is a proprietary formula of the Eastman Kodak Company and is no longer being produced. However, there are many published formulas which still call for it. The composition is known to be sodium metaborate, octahydrate. Sodium metaborate is commonly sold in the octahydrate state, as it is the most stable. Therefore, weight-for-weight substitution can be made. 

Sodium carbonate can also be used as a substitute for Balanced Alkali. Two parts by weight of Balanced Alkali is approximately equivalent to 1 part by weight of sodium carbonate, monohydrate, in normal developers. A more precise substitution is to use 5.9 grams of sodium carbonate, monohydrate, for each 10.0 grams of Balanced Alkali. 

Yet another substitution is to use 4 parts sodium carbonate, monohydrate, and 1 part borax to equal the same weight of Balanced Alkali (e.g., 10.0 grams of Balanced Alkali equals 8.0 grams of carbonate and 2.0 grams of borax). 

Notes A sludge of basic aluminum sulfite is occasionally formed when a developer containing sodium carbonate reacts with a partially exhausted acid-hardening fixing bath. This sludging tendency of certain fixing baths is minimized when developers containing Balanced Alkali are used. 

Substitutions Balanced Alkali (Kodalk) can be used as a substitute for carbonate or vice versa. Sodium carbonate is commonly available in anhydrous and monohydrous forms. The crystalline form is available as Arm Hammer Washing Soda, which is sodium carbonate decahy-drate (use the yellow, unscented box). This can be safely substituted in almost all formulas calling for carbonate. 

Trade Names Kodak Balanced Alkali, Kodalk. 

Substitutions Sodium metaborate, octahydrate (8H20), and Balanced Alkali (Kodalk) are, for all practical purposes, the same. Substitution can be made weight for weight. 

Water at 125F/52C, 750.0 ml Metol, lO.Og Sodium sulfite, lOO.Og Balanced Alkali, 20.0 g Water to make 1.0 liter... 

Water at 125F/52C, 750.0ml Metol, 5.7g Sodium sulfite, 90.0g Balanced alkali, 22.5 g Potassium bromide, 2.0g... 

PAPER For warm tones on papers, use without dilution and develop for about 2 minutes at 68F/20C. For colder tones, double the quantity of balanced alkali use without dilution and develop 1 to 2 minutes. 

Most fixers have strong odors caused by sulfur dioxide. The substitution of balanced alkali for boric acid in the F-6 formula eliminates the odor almost entirely. 

Sodium carbonate, mono. Balanced Alkali or Sodium ... 

Balanced Alkali or sodium metaborate, octahydrate Sodium carbonate, mono. 0.59... 

The well-known pigmentary bronzes, which are electrical conductors and show a range of colours, contain reduced forms of WO3. In these compounds, a limited number of are replaced by cations, but the total number of O atoms remains constant. In order to maintain charge balance, alkali metal cations can be introduced in the otherwise empty channels to stabilise the structure ... 

Also see ACID-BALANCE ALKALI RESERVE BAKING POWDER AND BAKING SODA and BICARBONATE ION.)... 

Inorganic polymers, also known as geopolymers, are aluminosilicates, conventionally prepared by condensation of a solid aluminosilicate such as the dehydroxylated clay mineral metakaolinite with an alkali silicate solution under highly alkaline conditions. At ambient temperatures these materials set and harden to an X-ray amorphous product containing solely tetrahedral A1 and tetrahedral Si characterised by a broad Si MAS NMR resonance at about -92 ppm. The most recent Na MAS NMR studies have provided more details about the way in which the charge-balancing alkali ions are incorporated in the structure. 

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