Borate Silicates

These pigments, also termed core pigments, such as phosphate silicates (see Section 5.2.5.3),consistofa complex composite of alkaline earth silicates, like calcium silicate. Available commercial grades differ primarily in their B2O3-content and oil absorption value (Table 5.9) [5.53]. 

They are mainly recommended for application in protective coatings based on solvent-borne alkyd resins [5.83]. 

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Alkalinity An expression of the total basic anions (hydroxyl groups) present in a solution. It also represents, particularly in water analysis, the bicarbonate, carbonate, and occasionally, the borate, silicate, and phosphate salts which will react with water to produce the hydroxyl groups. 

When chemical treatment for both HW heating and LP steam heating systems is generally some combination of a nitrite/borate/silicate/ molybdate formulation, usually with TTA/polymer or phosphate but having no specific oxygen-scavenging capability. 

The primary types of corrosion inhibitor treatments employed are generally based on inorganic chemicals such as sodium nitrite (together with combinations of borate, silicate, molybdate, and phosphate) and the addition of even 2 to 3 pints (0.95-1.4 liters) to a boiler can immediately raise the TDS in the BW to a level at which priming can occur. Secondary problems include an associated rise in the level of BW suspended solids and sludge. 

Unfortunately, such simple estimations can be in error. Hydroxyl, borate, silicate, ammonia, phosphate, and organic species can contribute to the solution s ability to buffer acid. For example, each of the reactions,... 

It was foimd that, in the sequence sulfates, phosphates, borates, silicates, aluminates, and simple oxides the probability of observing normal df emission decreases and the probabiUty of observing anomalous emission or no emission at all increases. Normal df emission is only observed in the sulfates MSO4 (M=Ca, Sr, Ba) and in the condensed borate SrB407. Anomalous emission... 

In investigations of structures of amorphous solids, MAS NMR spectroscopy has been used effectively (see Chapter 2). Structures of borates, silicates and phosphates have been advantageously studied by this technique. An important advance in this area... 

If the ion-exchange capacity of the separator column is sufficiently low and if dilute eluent is used, ion suppression is unnecessary. Also, anions of weak acids, such as borate, silicate, sulfide, and cyanide, cannot be determined with ion suppression, because these anions are converted into very weakly conductive products (such as H2S). 

Most of the chemicals used in fire-retardant formulations have a long history of use for this purpose, and most formulations are based on empirical investigations for best overall performance. These chemicals include the phosphates, some nitrogen compounds, some borates, silicates, and more recently, amino-resins. These compounds reduce the flame spread of wood but have diverse effects on strength, hygroscopicity, durability, machinability, toxicity, gluability, and paintability (J, 12, 13). 

HPICE Ion- exclusion -SO, HC1 Octane-sulfonic acid aliphatic carboxylic adds, borate, silicate, carbonate, alcohols, aldehydes... 

Anions of strong acids may be separated in acidic solution (as in Fig. 6.10) or at a basic pH. Weak acid anions require a basic solution to exist in the anionic form. Separation of borate, silicate, sulfide, cyanide as well as the anions of two stronger acids is shown in Fig. 6.11. An alkaline solution of sodium benzoate was used as the eluent. Carbonate may also be separated under alkaline conditions. Separation of these anions by suppressed IC is usually not attempted because they arc converted to the non-conducting molecular form by the acidic suppressor. 

Eluting anions Borate Silicate Formate Sulfide Chloride Cyanide... 

Alkalinity may be defined as the excess of anions of weak acids in seawater, so it is a measure of the ability to react with H+ ions the higher the alkalinity of a solution, the greater its capacity to react with H+. There are also minor contributions to alkalinity from anions of other weak acids such as borate, silicate and phosphate. Water can be considered a weak acid its contribution to alkalinity is the difference between the hydroxyl and proton concentrations. Total alkalinity can be defined as ... 

Other compounds present in natural water may also make a minor contribntion to alkalinity. For example, ammonia and salts of weak inorganic acids snch as borates, silicates and phosphates may contribute to alkalinity, as may salts of organic acids (e.g., humic, acetic, propionic). 

Alkalinity A measure of the buffer capacity to resist drop in pH when acid is added, i.e. it is the measure of the chemical constituents of water that react with hydrogen ions, and thus resist a decrease in pH. The major portion of alkalinity is due to hydroxide, carbonate andbicarbonate. Other contributors include salts of weak acids such as borates, silicates, phosphates, and organic acids such as humic acid. Alkanitiy can be expressed as M alk. to a methyl orange titration end point (pH 4.2) or P alk. to a phenolphthalein end point (pH>8.2). 

Mossbauer spectroscopy has been successfully used to clarify the iron chemistry in glass science. Mainly borate, silicate and phosphate glasses have been extensively studied. A detailed bibliography is presented in [15]. Due to the rapid development in this area it is not possible to summarize the whole field. 

This evidence of the uptake of inhibitive anions into oxide films forms the basis of the chemical or pore plugging theory of inhibition, associated originally with Evans etal. In this theory the rdle of the inhibitive anion is to promote the repair of weak points or pores in the oxide film, where corrosion has started, by reacting with dissolving iron cations to form insoluble products of separate phase, which plug the gaps. These insoluble products may contain the inhibitive anion either as a salt, e.g. phosphate, or a basic salt, e.g. azeiate , or as an insoluble oxide, e.g. CrjOj from chromate Precipitation of such solid products is favoured if the pH in the region of the pores does not become acid. Thus, on the basis of this theory, inhibition by anions such as phosphate, borate, silicate and carbonate, is enhanced by their buffer properties which serve to prevent a fall in pH in the anodic areas. Since ferric salts are usually more insoluble than... 

Anions of strong or medium-strength acids may be separated at a moderately acidic pH (as in Figure 6.12) or at a basic pH. However, anions of very weak acids such as borate, silicate or cyanide require a basic pH to be sufficiently ionized for separation and detection. Detection of these anions by suppressed conductivity is not very feasible because the suppressor converts the anions into the weak acid. However, anions of both weak and strong acids are nicely separated by elution with an alkaline solution of sodium hydroxide or sodium hydroxide and sodium benzoate as the eluent. (Figure 6.14) Detection was by indirect conductivity and the peaks represent a decrease in conductivity. 

Gas-solid Ha-Pd, Ni, Pt, Cu Oj-Ag, GujO, FeO Na-W, Mo, Fe Ha-KBr Ha-SiOa, pyrex, rubber, cellulose Oa-SiOa Na-SiOa Ar, Ne, He-SiOa, BaOj, borates, silicates, i ubber, cellulose... 

Produced water is an extremely complex chemical solution, comprised of liquid water, minerals dissolved from formation rocks, and water soluble organics from the hydrocarbon phase. The most important inorganic compounds with corrosion implications are chlorides and buffering compounds (bicarbonate, borate, silicate, etc.). The presence of buffering compounds reduces corrosion by raising the solution pH, compensating for the effect of dissolved acid gases. An accurate, detailed analysis of the... 

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