Heavy Medium Cyclone Research Articles

Computer Simulation of The Bullmoose Coal Preparation Plant

A customized computer simulation program was developed in Microsoft Excel for the Bullmoose coal preparation plant, which is a 450 t/h coal cleaning facility located in northeastern British Columbia, Canada. Upon specification of raw feed characteristics and plant operating parameters, the program predicts the overall plant performance, as well as the performances of individual cleaning circuits that comprise heavy media cyclone, spiral, and flotation. The program also includes an optimization module, which can be used to determine the necessary plant operating conditions to satisfy the "110 Model," an internal performance benchmark. The simulator has been tested against actual plant data and found to be reliable within the scope of investigations. Examples are provided to demonstrate the use of the simulator in investigating the effect of some of the important process variables, namely the frother concentration and heavy media slurry density.

Fine Coal Cleaning by Spiral and Water Washing Cyclone

The performance of three different types of spirals and a 200 mm diameter water washing cyclone have been assessed in open-circuit on-site testwork at the Norwich Park preparation plant on nominally 500 µ x 75 µm sized coal. The study is part of a program investigating alternative methods to heavy media cyclones and froth flotation for removing ash from fine coal from Central Queensland mines in the nominally 3 mm x 75 µm size range. The two spirals specifically developed for treating fine coal showed better cleaning efficiencies than the water washing cyclone on the +75 µm size fraction in the feed (essentially 1 mm top size). Their single start capacity was about half that of the water washing cyclone for the same clean coal ash content. The spirals readily produced a high ash reject (> 81%) in a single stage and, with the appropriate splitter configuration, a small middlings suitable for retreatment. Middlings splitter setting and vortex finder position (for the water washing cyclone) both provided reasonable control of clean ash at intermediate solids feed rates. For the spirals there was a strong correlation between solids feed rate and both clean coal ash content and yield at constant middlings splitter setting. For small cuts to middlings, separation efficiency remained relatively constant over the full range of feed rates. Relative density partition data indicated that less size classification took place in the spirals although the efficiency of both processes decreased sharply below about 125 µm. For a given clean coal ash the capacity and/or recovery of the spirals and water washing cyclone depended on tshe proportion of -75 µm high ash slimes in the feed.

Trace Element Removal During Physical and Chemical Coal Cleaning

Abstract Trace elements in coal are detrimental from both an environmental and a technological perspective. Since most trace elements in coal are associated primarily with the mineral phases, they are often amenable to removal by conventional physical coal beneficiation methods. However, these methods generally are not adequate for removing those trace elements which are associated with the organic matrix or which are very finely disseminated. Thus, chemical treatments may be necessary for removal of these trace components. Data from a variety of studies indicate that cleaning by concentrating tables, jigs, heavy-media cyclones, hydrocyclones, froth flotation, and oil agglomeration could effectively remove many trace elements from some coals. However, trace element removal efficiencies varied widely between coals. Because cleaning efficiencies are strongly coal-dependent, conclusions regarding the relative effectiveness of various cleaning techniques are difficult to draw since different coals were used a...

Recent advances in fine coal beneficiation

The quantum of coal fines below 6 mm in run-of-mine (ROM) coal has been increasing due to progressive mechanization of mining methods which has created a substantial incentive, worldwide, to develop suitable fine coal beneficiation techniques. The majority of the efforts have been directed toward reduction in ash/sulfur contents in clean coal. The beneficiation techniques may be broadly grouped as those based on specific gravity and surface property. The processes, which use heavy medium cyclone, water-only cyclone, concentrating tables, and spirals, belong to the former group while the latter group encompasses froth flotation, column flotation, oleoflotation, and oil agglomeration. In almost all the gravity based techniques, it has been noted that a classification step prior to beneficiation is essential for effective treatment. In general, the effect of design and process variables on the performance of these units and also the quantification of the processes have been the main areas of research and development. In froth flotation, efforts throughout the world have been mainly to understand the effect of variables and to optimize the process. Quantification of the process has been attempted through kinetic studies and mathematical modeling. The efforts have led to the development of new reagents, machine designs, and flowsheets for a specified objective. The attempts so far with the column flotation and oleoflotation processes have indicated a great potential. Extensive R&D efforts are in progress to understand as well as to commercialize the processes. The efforts in the oil agglomeration process have been toward substantiating the inherent merits of the process by developing cheaper bridging liquids and technology to recover and reuse the oil to make the process commercially viable. Modeling of the process has also been attempted to predict the yield and size distribution of the agglomerates. This paper reviews and summarizes the recent developments in the science and technology of fine coal beneficiation processes. The current trends in R&D efforts for these processes are also highlighted.

Effect of some operating variables on the performance of a 76 mm heavy medium cyclone

Tests were carried out on a 76 mm heavy medium cyclone-treating coal. The results show that the specific gravity of separation of coal is influenced not only by the specific gravity of the feed medium but also by the magnetite to coal ratio in the feed slurry.

Organic Pollutants in Wastes and Process Streams of Coal Cleaning Plants

Abstract Process waters and coal wastes from the physical cleaning of coals were collected at heavy media cyclone and water washing plants. The process wastewaters and leachates of the wastes were extracted and the organic compounds in these extracts were characterized by gas chromatography (GC) and combination gas chromotography/mass spectrometry (GC/ MS). Most of the identified compounds were aliphatic acids present at less than 1 mgL−1. Base/neutral compounds were present at less than 10μgL−1 in 22 different samples.

Studies on the Operational Characteristics of an Industrial Heavy Medium Cyclone

Abstract Tests were carried out on a 600 mm industrial heavy medium cyclone treating coal in the size range − 13.0 to +0.5 mm. The results indicate that the yield and ash content of the clean coal can be controlled by manipulating both the relative density of the feed and the spigot diameter. It has been shown that for the same proportion of heavier fraction in the clean coal, larger spigot openings accompanied with high relative density of the feed give more yield than smaller spigots operating with a low relative density of the feed medium. The misplaced heavier fraction in the clean coal has been found to be much finer than the misplaced lighter material in the discard. The specific gravity of separation of coal increases rapidly with increase in the relative density of the feed medium and for the geometry of the cyclone and the size range of the feed coal investigated under the conditions maintained, the relationship between the two has been found to be:- The generalised distribution curve for the operation has indicated that the lighter specific gravity fractions are separated more sharply than the heavier fractions in the feed. Mathematical relationships have been presented to estimate the relative density of the feed medium to be maintained for any desired yield or quality of the product.

Using Model Discrimination to Select a Mathematical Function for Generating Separation Curves

A statistical technique, known as model discrimination, is presented for selecting a mathematical function to fit separation data in order to estimate the characteristic parameters — the relative density of separation and the probable error. Some of the more commonly used functions are compared by their goodness of fit and their parameters evaluated statistically using a sensitivity analysis approach in order to determine the function with the best fit and the maximum parameter sensitivity. Application of this technique is demonstrated using sets of separation data from actual heavy media cyclone operations. For separator data exhibiting apparent bypassing, i.e., a fraction of feed apparently exiting with the clean coal and/or a fraction of feed apparently exiting with the refuse, a modelling technique is given whereby an existing function can be expanded to incorporate the bypass parameters.

Miner, A New Coal Stripping and Processing Simulator

To assist in reserve estimation and mine planning at its Oaky Creek coking coal property in Central Queensland/ Australia, Houston & Oil Minerals Australia, Inc., developed MINER. Using exploration and development drill-hole data, dragline specifications, preparation plant simulation data and a mining strip plan, MINER simulates overburden removal, coal extraction, and washing by heavy media cyclones (froth flotation for fines), to evolve the product specifications and materials handling statistics on a period by period basis for the mine plan. The history of the system from concept through implementation to its practical operation as a planning and development tool is discussed.

Resource recovery from solid wastes by water only cyclone process and heavy medium cyclone process

The water only cyclone processes and heavy medium cyclone processes, developed by Stamicarbon and applied for the separation of coal, ore and minerals for the last 25 years, were tested for resource recovery from automotive scrap, municipal solid waste, car batteries and incinerator residue. The first commercial plant for shredded automotive scrap has been in operation with success since January 1977. The results of this plant and of extensive test work have proven that the application of the cyclone technique can be very profitable for the resource recovery from all types of wastes, because of the high efficiency and the production of clean saleable products.