نوع مقاله : مقاله پژوهشی
نویسندگان
1 دانشکده مهندسی معدن و متالورژی، دانشگاه صنعتی امیرکبیر
2 دانشکده مهندسی معدن، دانشگاه کاشان
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Summary
Thickeners are the critical units in the hydrometallurgical processing operations and are used to separate solids from liquids. In the present study, the mixing pattern of pulp and clear water phases in the mixing duct known as E-DUC was calculated through computational fluid dynamics (CFD) and the effect of flow rate changes and solids content of the input feed on dilution before entering the feed well in Midouk copper thickener was studied. The flow rate and solids content of the feed under the operational conditions were 605.45 m3/h and 25%, respectively. Under these operational conditions, dilution of the feed flowing into the feed well was calculated 19.51 using simulations, which was an acceptable estimate of the actual dilution. Then, by changing the flow rate of the feed, the effect of this parameter on dilution of the pulp input to the feed well was determined. By increasing the flow rate to 700 m3/h, dilution levels rose to 28.5, respectively.
Introduction
One of the main methods of dewatering in mineral processing units is to settle the materials in the thickeners. Since studies have shown that reducing the concentration of the inlet pulp to the thickener is effective in improving its performance, often a mechanism has been used to increase the dilution of the inlet pulp, including the self-dilution system of the pulp using the clear water section at the top of the thickener. Given the powerful processors and the many advances that have been made in computational fluid dynamics, it is possible to simulate the performance of these structures in a thickener numerically.
Methodology and Approaches
The dynamic behavior of fluid was studied by modeling the continuity and Navier-Stokes equations in Fluent version 14.5. The k-ε library function was used to apply turbulent flow conditions and the mixture model was used to study multiphase flows.
Results and Conclusions
The simulation of the plant operating conditions by the model showed that due to the pressure drop around the nozzle, water enters the E-DUC channel. The dilution of pulp increases as a result of mixing the two phases of the pulp and water before entering the feed well. The result is in excellent compliance with the conditions in the thickener, which may indicate the accuracy of the obtained model. The simulation showed that with increasing the inlet feed flow, the dilution of the inlet pulp raised more than the current situation.
کلیدواژه‌ها [English]
در دهه‌های اخیر سیستم‌های نوین متعددی برای آبگیری باطله‌های کارخانه‌های کانه‌آرایی معرفی و در مقیاس صنعتی پیاده‌سازی شده‌اند. اهمیت روز افزون بازیابی و مدیریت آب در کارخانه‌ها، روند استفاده از فناوری جدید را شتاب بیشتری بخشیده است. با توجه به محدودیت آب در اغلب کارخانه‌های فرآوری مواد معدنی ایران بدیهی است که شناخت این فناوری و استفاده از آن می‌تواند نقش بسیار مهمی در بهره‌برداری بهینه از منابع موجود ایفا نماید]1[. یکی از اصلی‌ترین روش‌های آبگیری در واحدهای فرآوری مواد معدنی، تهنشین کردن مواد در تیکنرها است. مکانیزم تیکنرها به این صورت است که دوغاب وارد یک چاهک خوراک مرکزی میشود. چاهک خوراک بدین منظور قرار داده شده است که انرژی جنبشی جریان ورودی را کاهش داده و جریان را به منطقه اصلی تیکنر هدایت میکند. جامدهای تهنشین شده تشکیل یک بستر میدهند و غلظت جامد در این بستر به سمت خروجی افزایش مییابد. مایع عاری از جامد در مخازن جانبی جمعآوری شده و از آنجا خارج میشوند.
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