Crystallisation of minerals from concentrated saline dairy effluent
| Autor: | Sally L. Gras, Sandra E. Kentish, Bogdan Zisu, George Q. Chen, Judy Lee, M. Weeks, Kezia Kezia |
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| Rok vydání: | 2016 |
| Předmět: |
Environmental Engineering
Sodium chemistry.chemical_element 02 engineering and technology Sodium Chloride 010402 general chemistry 01 natural sciences 7. Clean energy law.invention chemistry.chemical_compound law Mass transfer Crystallization Waste Management and Disposal Effluent Water Science and Technology Civil and Structural Engineering Minerals Ecological Modeling Temperature 021001 nanoscience & nanotechnology Total dissolved solids Phosphate Pollution 6. Clean water 0104 chemical sciences Solutions Crystallography Brine Calcium carbonate chemistry Chemical engineering 0210 nano-technology |
| Zdroj: | Water Research. 101:300-308 |
| ISSN: | 0043-1354 |
| DOI: | 10.1016/j.watres.2016.05.074 |
| Popis: | An understanding of crystallisation within saline effluents is important for the design of both brine crystallisers and brine disposal ponds. In this work, crystallisation of a saline effluent concentrate from the Australian dairy industry has been examined at 22 wt% and 30 wt% total solids and at temperatures between 10 and 70 °C. The precipitation occurs more rapidly at higher temperatures. This trend is dictated by precipitation of calcium phosphate salts, albeit the major constituents of the mixture are NaCl and lactose. The crystallisation induction time can be shortened by introducing cavitation induced by ultrasound. In particular, the use of two short acoustic pulses between 3.7 J/g and 16 J/g at 20 kHz spaced ten minutes apart has maximum impact upon both induction time and crystal size. It is believed that the first ultrasound pulse either generates new nuclei or enhances the mass transfer of solute toward the surface of sub-micron growing crystals. Conversely, the second pulse disrupts the growing crystals and forms secondary nuclei. The ultrasound cannot shift the solution equilibrium and so is not able to improve the low crystal yield. To increase this total yield, further evaporation is necessary. The work provides direction to personnel in the dairy industry of the feasibility of brine crystallisation with respect to energy demand and solid recovery. |
| Databáze: | OpenAIRE |
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