143 rd SME Annual Meeting 26 February 2014 Mike Albrecht, PE Teaching new employees about processing equipment What it is and how it works

143 rd SME Annual Meeting 26 February 2014 Mike Albrecht, PE What are these? Storage tanks, surge tanks, float cells, or leach tanks?

143 rd SME Annual Meeting 26 February 2014 Mike Albrecht, PE Some recent questions – How do you separate magnetite from beach sands? – How does a dense media system work? – What are the key parameters to control in cyclone separation of solids, for a SAG mill discharge? – Can somebody give me a good orientation of how a cyclone separation works? – Does anyone have any experience in Magnetic separation in the aqueous phase?

143 rd SME Annual Meeting 26 February 2014 Mike Albrecht, PE What it is and how it works We use some large and unusual equipment. Understanding it is important to good operations How do you teach a new employee. This presentation will be an introduction – in particular to gravity separating equipment.

143 rd SME Annual Meeting 26 February 2014 Mike Albrecht, PE Jigs Principles of particle motion under pulsed- flow hindered-settling conditions. Separating mechanisms are: – hindered settling, – differential acceleration, – and consolidation trickling.

143 rd SME Annual Meeting 26 February 2014 Mike Albrecht, PE Jigs The particles became rearranged in layers of increasing density from bottom to top. Jigging can be applied to a wide size-range of particles with top sizes up to 200 +mm.

143 rd SME Annual Meeting 26 February 2014 Mike Albrecht, PE Jigs

143 rd SME Annual Meeting 26 February 2014 Mike Albrecht, PE Dense Media Vessels Feed is slurried in a medium with a specific gravity close to that of the desired separation. – The lighter fraction floats – and the heavier fraction sinks. Heavy medium are suspensions of magnetite or ferrosilicon in water.

143 rd SME Annual Meeting 26 February 2014 Mike Albrecht, PE Dense Media Vessels

143 rd SME Annual Meeting 26 February 2014 Mike Albrecht, PE Dense Media Cyclone Similar to a vessel, a slurry of ore and medium (magnetite or ferrosilicon dispersed in water) is admitted at a tangent to the cyclone. The higher specific gravity moves along the wall of the cone and is discharged at the apex. The lighter particles of lower specific gravity move toward the longitu­dinal axis of the cyclone and through the vortex finder.

143 rd SME Annual Meeting 26 February 2014 Mike Albrecht, PE Dense Media Cyclone

143 rd SME Annual Meeting 26 February 2014 Mike Albrecht, PE Tables Separation is by flowing film. The feed fans out over the table deck by: – differential motion – and gravitational flow The particles become stratified in layers behind the riffles.

143 rd SME Annual Meeting 26 February 2014 Mike Albrecht, PE Tables This stratification is followed by the removal of successive layers from the top downward by cross-flowing water as the stratified bed travels toward the outer end of the table

143 rd SME Annual Meeting 26 February 2014 Mike Albrecht, PE Tables

143 rd SME Annual Meeting 26 February 2014 Mike Albrecht, PE Water-only Cyclone Similar in operation to Dense Media cyclones, but with no media, using only water and inertia, because of the wide angle or angles in its conical bottom. Predominately used in coal, and a few other applications.

143 rd SME Annual Meeting 26 February 2014 Mike Albrecht, PE Water-only Cyclone

143 rd SME Annual Meeting 26 February 2014 Mike Albrecht, PE Launders/Sluices Launders/Sluices have been used for mineral processing almost as long as jigs (or perhaps longer). They are simple to build and operate, but require a relatively large amount of space for processing anything more than a few pounds an hour of material.

143 rd SME Annual Meeting 26 February 2014 Mike Albrecht, PE Launders/Sluices

143 rd SME Annual Meeting 26 February 2014 Mike Albrecht, PE Spirals Spirals are a more recent development than launderers and date from the mid 20 th Century (CE). While essentially a spiral launder the force on the particles from the centripatel action enhances separation.

143 rd SME Annual Meeting 26 February 2014 Mike Albrecht, PE Spirals

143 rd SME Annual Meeting 26 February 2014 Mike Albrecht, PE Centrifugal Concentrators Particles >0.5 mm a water based gravity separation process is very efficient. 0.5 mm to 0.1 mm efficiency drops off, but the devices can still be effective. < 0.1 mm or with a small density difference, the speed with which the particles will move apart maybe less than the speed at which the water is flowing.

143 rd SME Annual Meeting 26 February 2014 Mike Albrecht, PE Centrifugal Concentrators One solution - increase the force on the particles by speeding up their movement. Centrifugal concentrators can increase the force to 50 to 150 times They can separate particles which previously where impossible to separate by other than flotation or chemical processes.

143 rd SME Annual Meeting 26 February 2014 Mike Albrecht, PE Centrifugal Concentrators

143 rd SME Annual Meeting 26 February 2014 Mike Albrecht, PE Flotation Flotation - a physicochemical method. It involves chemical treatment of a pulp to create conditions favorable for the attachment of particles to air bubbles. Some particles are not readily wetted by water (hydrophobic), While others are readily wetted by water (hydrophilic).

143 rd SME Annual Meeting 26 February 2014 Mike Albrecht, PE Flotation By the addition of chemicals these proper­ties can be enhanced. Air bubbles are created by the agitator mechanism which draws air down the shaft. The air bubbles carry the hydrophobic particles to the surface of the pulp Form a froth which is skimmed off The hydrophilic particles remain in the pulp.

143 rd SME Annual Meeting 26 February 2014 Mike Albrecht, PE Flotation

143 rd SME Annual Meeting 26 February 2014 Mike Albrecht, PE What are these? Float Cells

143 rd SME Annual Meeting 26 February 2014 Mike Albrecht, PE More Information Agricola, Georgius. (1556). “De re metallica.” Translated 1950 translated by: H. C. Hoover, L.H. Hoover. Dover, NY. Albrecht, M. C. (2013), “A Mining Engineers Notebook”, http://