| Autor: |
Vysotskiy, Sergiy, Varyvoda, Oleksiy |
| Zdroj: |
Eastern-European Journal of Enterprise Technologies; 2013, Vol. 6 Issue 6, p57-61, 5p |
| Abstrakt: |
The main form of deposits in the circulating water systems is the crystals of calcium carbonates and iron compounds. The crystals of calcium carbonate are formed as a result of transition of carbon dioxide to the gas phase. The studies of the crystallization of calcium carbonate from water solutions of calcium hydrogen carbonate with and without the addition of corresponding salts were carried out. To confirm the influence of the surface-active substances (SAS) OP-7 and OP-10 on the crystallization processes, a series of experiments at different dosages of SAS were performed. The increase in the heating temperature and solution concentration leads to the increase in the size of crystals, depositing on the glass plate. Small crystal formations are unstable and can be dissolved under the influence of fluctuations of hydrodynamic flows, as well as under the influence of physicochemical processes due to the shift of the calcium carbonate equilibrium under the influence of fluctuations of the concentration of carbon dioxide. Anti-scale additives of hexametaphosphate and tripolyphosphate type reduce the intensity of scale formation and change the conditions of calcium carbonate crystallization. In all experiments when using hexametaphosphate with the concentration of 10 mg/dm³ and tripolyphosphate from 1 to 500 mg/dm³ as the additives, very small calcite crystals of 1-2 microns in size are formed. All other things being equal, the reduction in the concentration of tripolyphosphate to 0.5 mg/dm³ leads to the formation of crystals in the form of "needles" and "flowers" with the size of 100-160 microns. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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