کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
233049 465320 2015 5 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Modelling of residence time distribution of liquid and solid in mechanical flotation cells
ترجمه فارسی عنوان
مدل سازی توزیع زمان ماندن مایع و جامد در سلولهای فلوتاسیون مکانیکی
کلمات کلیدی
توزیع زمان اقامت، سلول های مکانیکی، شناور مخلوط کردن رژیم
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی مهندسی شیمی (عمومی)
چکیده انگلیسی


• Industrial RTD data recorded in mechanical flotation cells were modelled.
• It was concluded the mixing regimes cannot be described by a unique model structure.
• Three conditions were observed with significant channeling in single cells.
• The arrangement of cells in series was effective in reducing by-pass.
• By-pass propagation was observed in some operations.

This paper presents the results of modelling the residence time distribution (RTD) in mechanical flotation cells, measured in several plants, using the radioactive tracer technique. Results include mechanical cells of 100–300 m3 operated with effective residence times from 2 to 7 min. Data were obtained in forced air and self-aerated cells for liquid and non-floatable solids (per size classes). Different RTD model structures including perfect mixing, Large and Small Tanks in Series (LSTS) and by-pass flow plus perfect mixing were evaluated and compared for single cells. The actual mixing regimes were related to the effective residence times and cell designs based on the model fitting. By-pass flow percentages were typically lower than 10%, therefore the perfect mixing model plus a dead time was a suitable model structure in most cases.On the other hand, the arrangement of cells in series was in most cases effective in reducing the bypass flow observed in single cells. In addition, the N mixed tanks-in-series model was used to represent the mixing regime along flotation banks, which were operated with mean residence times in the range of 18–53 min. Results showed that the N equivalent tanks-in-series values were closer to the actual values in most cases. In some applications, slight by-pass propagation was observed because of circuit layout, problems with the level control system, solid settling and/or high flowrates.

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ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Minerals Engineering - Volume 78, July 2015, Pages 69–73
نویسندگان
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