The invention is based on the discovery that the reason why big hydrocyclones which are positioned vertical need a comparatively high feed pressure is that, owing to their great length, these hydrocyclones contain such a tall liquid column that gravity becomes an important factor and influences the operation of the hydrocyclone. If however, the hydrocyclone … Read more
Hydrocyclones are currently the most commonly used classifiers in wet closed circuit grinding systems. Some recent papers, however, give evidence that high frequency vibrating screens can be a viable alternative to hydrocyclones for a wide variety of grinding applications. In principle, classifier selection for closed circuit grinding should be based on an evaluation of the … Read more
The industrial grinding process has undergone changes to better address the market and economic needs. Fine grinding of dry materials has developed to the point where classifying linings and fine ball charges improve mill efficiencies. Roller mills as well have wide acceptance due to their power efficiencies. The mill, by its nature, cannot provide the … Read more
Minerals beneficiation commonly requires initial crushing and grinding so that the mineral phase we seek to concentrate is adequately liberated to obtain a product of specified grade at optimum recovery. To some degree this also is true for coal preparation. In the comminution process we liberate not only the product but also the tailings phase. … Read more
The Island Copper concentrator was designed to process 30,000 t/d of copper ore containing 0.52% Cu and 0.017% Mo with payable gold, silver, and rhenium values. Separate copper and molybdenum flotation concentrates are produced and currently sold to customers in Asia, Europe and the North America. The comminution circuit as originally installed comprised single stage … Read more
A very important factor in froth flotation is the use of surface-active chemicals to form a froth in which minerals or coals are retained, thus allowing for valuable component enrichment. Despite the importance of frothers, surprisingly little systematic scientific work has been performed with the goal of quantifying frother mechanisms and the influence of particle … Read more
Pilot-scale tests indicate that effective concentration of fine gold from Colorado River sands can be achieved by flotation with the air-sparged hydrocyclone. The fine sands (55% minus 400 mesh and 0.01 opt) from gravity concentration were processed with a 5-cm air-sparged hydrocyclone (capacity -1.0 tph dry solids). Concentrate grades as high as 5.0 opt were … Read more
It is now well documented that trace amounts of silver, gold, and platinum group metals occur in certain geothermal brine deposits. A significant body of literature has been generated over the last twenty years which describes attempts to quantify the frequency and levels of these precious metals in the brines. There are numerous reports of … Read more
The SAG milling of ores with markedly variable grinding rates presents definite process control challenges. Decisions must be made regarding the selection of the most appropriate combination of mill volumetric load level, percent solids, and mill speed for the combination of ore types being processed at the moment. Circuit Description Chino’s concentrator is described in … Read more
The moisture content of coal has become more important in the product analysis. The high content surface area and corresponding high moisture of fine coal can contribute to most of the overall product moisture. As the preparation engineer exhausts his talents and capital budget to bring product moisture into compliance, alternate methods of fine coal … Read more