Mining Engineering Commons^™

Cavitation Nanobubble Enhanced Flotation Process For More Efficient Coal Recovery, Ahmed S. Sayed Ahmed

Theses and Dissertations--Mining Engineering

Froth flotation is a widely used, cost effective particle separation process. However, its high performance is limited to a narrow particle size range, e.g., between 50 µm and 600 µm for coal and between 10 µm and 100 µm for minerals. Outside this range, the efficiency of froth flotation decreases significantly, especially for difficult-to-float particles of weak hydrophobicity (e.g., oxidized coal).

Nanobubbles integrated into a specially designed column flotation expanded the particle size range for efficient froth flotation as a result of increased probabilities of particle- bubble collision and attachment and reduced probability of detachment.

The major advantages of nanobubble …

Froth Flotation Performance Enhancement By Feed Cavitation And Magnetic Plastic Particle Addition, Mehmet Saracoglu

Theses and Dissertations--Mining Engineering

Froth flotation is the most commonly used process to recover and upgrade the portion of the coal preparation plant feed that has a particle size smaller than 150 microns. Problems that occur when employing froth flotation in the coal industry include i) coal surfaces that are weakly-to-moderately hydrophobic, and ii) flotation systems that are overloaded and limited by insufficient retention time.

Research was performed to evaluate techniques that could be implemented to improve flotation performance under the aforementioned scenarios. Pre-aeration of flotation feed using a cavitation system was extensively evaluated in laboratory and full-scale test programs. The benefits of adding …

Enhanced Phosphate Flotation Using Novel Depressants, Lingyu Zhang

Theses and Dissertations--Mining Engineering

Froth flotation is the most efficient method for phosphate separation, which is a physic-chemical separation process based on the difference of surface properties between the valuable minerals and unwanted gangue minerals. However, the presence of clay slimes in the slurry after grinding consumes a large amount of reagents, decreases the collision probability between bubbles and minerals, prevents phosphate particle attachment to air bubbles, and thus considerably reduces flotation recovery and concentrate grade. Georgia Pacific Chemical, LLC has recently developed novel depressants, i.e., clay binders, which are a series of low molecular weight specialty polymers to help improve phosphate flotation performance …

Collectors For Enabling Flotation Of Oxidized Coal, Raghav M. Dube

Theses and Dissertations--Mining Engineering

The coalburg seam coal is an example of difficult to float bituminous coal. Laboratory tests conducted on coalburg flotation feed sample revealed recovery values around 28% with 15% product ash when using fuel oil as collector under natural pH conditions. A detailed study showed that increasing pH from natural value of 5.6 to 7.5 provided a significant improvement in recovery of approximately 32 absolute percentage points. The improvement is believed to be result of the release of humic acids from the surface and the dispersion of clay particles thereby leaving a more hydrophobic surface.

Based on the tests conducted with …

Development Of Strategies To Minimize The Release Of Trace Elements From Coal Waste Sources, Mohammad Rezaee

Theses and Dissertations--Mining Engineering

To assess strategies aimed at minimizing the release of trace elements and the impact of disposal of coal waste materials on the environment, two long-term leaching experiments of up to five months duration were performed using waste materials from two plants cleaning high and low sulfur bituminous coal. The tests evaluated the mobility of major trace elements under different disposal scenarios: (i) a static leaching test designed to simulate the quiescent conditions encountered by coal waste material stored under water in a stable impoundment, and (ii) a dynamic test to simulate waste materials exposed to the atmosphere, either in variable …