Iodine Gold Leaching
Over the last few years there has been an intense effort to identify lixiviants other than cyanide for gold and silver leaching. Bromide and iodide also exhibit the ability to form polyhalide complexes. This characteristic promotes the dissolution of Br2(s) and I(2)s in aqueous solution. Iodine reacts with iodide ion as follows: I(2)s = I2(aq)………………………………………………………..(1) I2(aq)+ […]
Improving Acid & Fluxed Pellet Metallurgical Properties
Production pellets from each Minnesota taconite operation were obtained for baseline metallurgical testing. Concentrate from several of the operations was obtained for more intensive studies. Bench scale pellets were produced using a balling tire and a mini-pot pelletizing furnace. The mini-pot has a .1 ft² area and fires approximately 2000 gms of green balls in […]
Determine Froth Flotation Kinetics
Froth flotation of minerals is one of the dominant concentration processes available today. By this process, finely divided mineral particles, within a pulp, separate according to the hydrophobicity of their chemically modified surfaces. Hydrophobic mineral particles are collected and transported from the pulp by air bubbles into the froth, along with some hydrophylic particles, which […]
Surfactants & Mine Dust Control & Effect on Flotation
Dust measurements in mines clearly indicated that the major mineral dust exposure is due to loading and transport of the ore from the mining areas. One approach to the solution of this dust problem is the application of water sprays to reduce dust dispersion. Wetting of broken rock is very effective in preventing fine dust […]
L / D Ratio in Overflow Ball Mill Design & Operation
Ball mill shape factors in the period prior to 1927 averaged 1.1/1 for 29 center discharge mills and 1.0/1 for 30 peripheral discharge mills. With the resumption of new plant construction after the 1930’s depression, the Morenci concentrator continued the 1/1 ratio with its 3.1 x 3.1 m (10 x 10 ft) mills. The ratio […]
Column Flotation Cell Residence Time Distribution RTD
We present the results obtained in a study of the residence time distributions of solids and liquids in two and three phase systems in a column flotation cell. The effects of various flotation parameters on these residence time distributions of the collection and cleaning zones are also reported. The data obtained was fitted to various […]
Factors Affecting Ball Mill Grinding Efficiency
The following are factors that have been investigated and applied in conventional ball milling in order to maximize grinding efficiency: a) Mill Geometry and Speed – Bond (1954) observed grinding efficiency to be a function of ball mill diameter, and established empirical relationships for recommended media size and mill speed that take this factor into […]
Recommended Ball Mill Speed & Liner Configuration
With particular reference to mill size, it is apparent that a change in diameter in a large mill is relatively far less significant than the same change in diameter for a small one. For example, using well established relationships between power draw and mill diameter and speed, 50 mm (2 inches) of liner wear results […]
Silver Refining
Precipitates mixed with diatomaceous earth from the precipitation filter unit are dried in a filter press and mixed with borax and soda ash. This mixture is then melted in a diesel-fired furnace and cast in a silver dore cone. This cone is then melted in another furnace into an anode 7 inches by 9 inches […]
Froth Washing in Mechanical Flotation Machines
Floatable and non-floatable particles follow different sequence for transport from the pulp to the froth and from the froth out of the cell. For floatable particles, the principal mechanism is true flotation (i.e. bubble attachment and levitatlon). Non-floatable particles arrive to the slurry-froth interface by hydraulic entrainment (i.e. wake carry over), mechanical entrainment (due to […]