The mechanisms of crystallization and transformation of calcium carbonates
نویسنده
چکیده
: The mechanisms of the formation and transformation of calcium carbonates and the inhibition by the phosphorus containing compounds were studied. Supersaturated solutions form the unstable polymorph, amorphous calcium carbonate, at first, followed by the transformation to the metastable polymorph which finally transforms to stable form, calcite. Transformation proceeds by a mechanism of recrystallization. The growth and transformation is strongly inhibited by a phosphorus containing compounds. Details of the adsorption mechanism were reported. The zeta potentials of calcium carbonates were determined at various solution conditions.
منابع مشابه
Dehydration and crystallization of amorphous calcium carbonate in solution and in air
The mechanisms by which amorphous intermediates transform into crystalline materials are poorly understood. Currently, attracting enormous interest is the crystallization of amorphous calcium carbonate, a key intermediary in synthetic, biological and environmental systems. Here we attempt to unify many contrasting and apparently contradictory studies by investigating this process in detail. We ...
متن کاملMolecular mechanisms of crystallization impacting calcium phosphate cements.
The biomineral calcium hydrogen phosphate dihydrate (CaHPO(4).2H(2)O), known as brushite, is a malleable material that both grows and dissolves faster than most other calcium minerals, including other calcium phosphate phases, calcium carbonates and calcium oxalates. Within the body, this ready formation and dissolution can play a role in certain diseases, such as kidney stone and plaque format...
متن کاملProto-calcite and proto-vaterite in amorphous calcium carbonates.
Crystallization of calcium carbonate, typically, progresses sequentially via metastabIc phases. Amorphous CaC03 (ACC) generally forms initially, both in vitro and in vivo, and is the precursor of the predominant anhydrous polymorphs (calcite, aragonite, and vaterite). [I-I3] A new picture of the crystallization of calcium carbonate is emerging, which involves transformations of clusters to ACC ...
متن کاملDistinguishing Anhydrate and Gypsum Scale in Mixing Incompatible Surface and Ground Waters During Water Injection Process
Determination of the type of precipitated calcium sulfate in mixing two incompatible injection and formation waters was studied experimentally in this work at two temperatures of 26oC and 80oC. Here the SEM, EDX and XRD techniques have been used to inspect the temperature effects on the morphology, type, and size of the precipitated calcium sulfate crystals. The result...
متن کاملThe role of amorphous precursors in the crystallization of La and Nd carbonates.
Crystalline La and Nd carbonates can be formed from poorly-ordered nanoparticulate precursors, termed amorphous lanthanum carbonate (ALC) and amorphous neodymium carbonate (ANC). When reacted in air or in aqueous solutions these precursors show highly variable lifetimes and crystallization pathways. We have characterized these precursors and the crystallization pathways and products with solid-...
متن کامل