Calcium carbonate inhibitors

Uses Deposit control additive, scale inhibitor in mfg. of paper/paperboard in contact with aq./fatty foods antisealant for oil field prod., water injection applies. calcium carbonate inhibitor in industrial water systems Regulatory FDA 21CFR 176.170 Trade Name Synonyms Bellasol S26 [BioLab... 

Calcium phosphate tribasic calcium carbonate inhibitor, industrial water systems... 

The second approach, changing the environment, is a widely used, practical method of preventing corrosion. In aqueous systems, there are three ways to effect a change in environment to inhibit corrosion (/) form a protective film of calcium carbonate on the metal surface using the natural calcium and alkalinity in the water, (2) remove the corrosive oxygen from the water, either by mechanical or chemical deaeration, and (3) add corrosion inhibitors. 

Precipita.tingInhibitors. As discussed earlier, the localized pH at the cathode of the corrosion cell is elevated due to the generation of hydroxide ions. Precipitating inhibitors form complexes that are insoluble at this high pH (1—2 pH units above bulk water), but whose deposition can be controlled at the bulk water pH (typically 7—9 pH). A good example is zinc, which can precipitate as hydroxide, carbonate, or phosphate. Calcium carbonate and calcium orthophosphate are also precipitating inhibitors. Orthophosphate thus exhibits a dual mechanism, acting as both an anodic passivator and a cathodic precipitator. 

External coil problems White calcium carbonate CaC03 Phosphate scale from threshold agents. Blue/green/black copper phosphate trihydrate Cu3(P04)2 3H20 Dirt pockets due to low level of coil. BW sludgei settles on external fins. Gasket weeping from inhibitor. Color stains from inhibitor dyes. 

Maleate chemistry has proved to be an enduring mainstay of many water treatment formulations, primarily as non-phosphate-containing calcium carbonate scale inhibitors. For most water treatment applications, polymaleic acid and its derivatives offer a good alternative to phosphonate chemistries, when required. 

Thennodynamic inhibitors are complexing and chelating agents, suitable for specific scales. For example, for scale inhibition of barium sulfate, common chemicals are ethylenediaminetetraacetic acid (EDTA) andnitrilotriacetic acid. The solubility of calcium carbonate can be influenced by varying the pH or the partial pressure of carbon dioxide (CO2). The solubility increases with decreasing pH and increasing partial pressure of CO2, and it decreases with temperature. 

The formation of calcium carbonate (CaCOs), calcium sulfate, and barium sulfate scales in brine may create problems with permeability. Therefore it is advantageous that newly made fractures have a scale inhibitor in place in the fracture to help prevent the formation of scale. Formulations of hydraulic fracturing fluids containing a scale inhibitor have been described in the literature [1828]. 

D. W. Fong, C. F. Marth, and R. V. Davis. Sulfobetaine-containing polymers and their utility as calcium carbonate scale inhibitors. Patent US6225430, 2001. 

Calcium carbonate requires an acidic medium for solubility ° H2-receptor antagonists and proton pump inhibitors... 

Calcium carbonate should be taken with food to maximize absorption. Elderly patients or patients receiving proton pump inhibitors or H2-receptor antagonists may have added difficulty absorbing calcium supplements because of reduced stomach acidity. Better absorption may occur in this setting with calcium citrate because an acid environment is not needed for absorption it may be taken with or without food. 

Semberova, J. et al. (2009) Carbon nanotubes activate blood platelets by inducing extracellular Ca2 + influx sensitive to calcium entry inhibitors. Nano Letters, 9 (9), 3312-3317. 

Reinforced plastics may also include fillers (qv), which are inexpensive materials such as calcium carbonate used to displace resin and reduce cost curing agents (catalysts), promoters, inhibitors, and accelerators, which affect thermosetting resin cure colorants release agents (qv) to facilitate removal from the mold and other additives which can impart a wide variety of properties to the finished part, such as fire resistance, electrical conductivity, static dissipation, and ultraviolet resistance. 

Interference with T4 absorption Cholestyramine, chromium picolinate, colestipol, ciprofloxacin, proton pump inhibitors, sucralfate, sodium polystyrene sulfonate, raloxifene, sevelamer hydrochloride, aluminum hydroxide, ferrous sulfate, calcium carbonate, bran, soy, coffee. 

These properties are still desired today in modem water treatment formulations. The phosphonates and newer organic polymers exhibit some or all of these effects, but modern inhibitors have considerably more hydrolytic stability, show a greater effectiveness in these properties, and have extended abilities, beyond that of controlling calcium carbonate crystalline scales. 

In practice, at the time, it was usual to destroy most or all of the alkalinity and reduce the pH to below 7.0 and often to as low as 6.0 because of the effectiveness of chromate inhibitor barrier films, it was not considered necessary to additionally practice a controlled calcium carbonate deposition program. 

PCA 16 is particularly effective for control of calcium sulfate deposition (and thus finds application, under different brand names and grades, as a calcium carbonate/sulfate scale inhibitor for RO systems treating brackish waters). This inhibitor is also useful for calcium phosphate control. It is stable against chlorine. 

AEC is a non-phosphonate calcium carbonate scale inhibitor, designed to be used under alkaline cooling water conditions (pH 7.8 to 9.0). It is halogen-stable, and is presumably positioned against PBTC, with the absence of phosphorus being promoted as an environmental benefit. 

In general, SS/MA and the other calcium phosphate inhibitors are not as good at inhibiting calcium carbonate scale as PMA or HEDP or as good at inhibiting calcium sulfate scale as PMA and 2000 MW PAA. 

A major portion of the studies on calcium carbonate reaction kinetics has been done in seawater because of the many significant geochemical problems related to this system. Morse and Berner (1979) summarized the work on carbonate dissolution kinetics in seawater and their application to the oceanic carbonate system. The only major seawater component in addition to Mg2+ that has been identified as a dissolution inhibitor is SO42- (Sjoberg, 1978 Mucci et al., 1989). Sjoberg s studies of other major and minor components (Sr2+, H3BO3, F-) showed no measurable influence on dissolution rates. Morse and Berner (1979) and Sjoberg (1978) found that for near-equilibrium dissolution in phosphate-free seawater, the dissolution rate could be described as ... 

The most complete study of the inhibition of calcium carbonate precipitation by organic matter was carried out by Berner et al. (1978), where primary concern was the lack of carbonate precipitation from supersaturated seawater. Both synthetic organic compounds and organic-rich pore waters from Long Island Sound were used to measure the inhibition of aragonite precipitation. Natural marine humic substances and certain aromatic acids were found to be the strongest inhibitors. The rate of precipitation in pore waters was also found to be strongly inhibited. 

Morse J.W. (1974) Dissolution kinetics of calcium carbonate in seawater. V Effects of natural inhibitors and the position of the chemical lysocline. Amer. J. Sci. 274, 638-647. 

Dextromethorphan-monoamine oxidase inhibitors Calcium carbonate-tetracycline... 

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