Magnesium scales from seawater distillation
| Autor: | Jacob Block, Bruce M. Watson |
|---|---|
| Rok vydání: | 1976 |
| Předmět: |
Chemistry
Brucite Magnesium Mechanical Engineering General Chemical Engineering Aragonite Analytical chemistry Alkalinity Mineralogy chemistry.chemical_element General Chemistry engineering.material law.invention Brining law engineering General Materials Science Seawater Hydromagnesite Distillation Water Science and Technology |
| Zdroj: | Desalination. 19:359-368 |
| ISSN: | 0011-9164 |
| DOI: | 10.1016/s0011-9164(00)88044-3 |
| Popis: | Seawater evaporation tests were run in the presence of typical distillation plant corrosion products, such as Fe, Ca and Ni. It was assumed that scales formed in this environment are more typical of the “real world” than scales formed under conditions with little or no corrosion taking place. Two types of tests were run, beaker tests using seawater and metal coupons, and flow tests using seawater and Cu-Ni tubing. By reducing the total alkalinity to less than 80 ppm, we were able to eliminate the formation of aragonite, and concentrate on the identification of the lesser known magnesium scales. Using X-ray diffraction spectroscopy, two different magnesium scales were identified. One, as expected, was brucite [Mg(OH)2], which was obtained under conditions of high temperature (110–120°C) and little or no residual CO2 in the brine. The other scale identified was iowaite [4Mg(OH)2·FeOCl·H2O], which was obtained at lower temperatures (100–110°C) and at higher residual CO2 in the brine. No evidence was found for the formation of hydromagnesite [3Mg(OH)2·MgCO3·3H2o], a scale previously proposed by other investigators. Tests with commercially available, threshold agent, Darex 41, tend to confirm the existence of two distinct Mg scales, since no threshold effect was observed for Mg(OH)2 formation, but a threshold effect was observed for the Mg scale formed at lower temperatures, i.e., iowaite. |
| Databáze: | OpenAIRE |
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