Iron ore (Hematite) mining companies generally produce two Direct Shipping Ore (DSO) products: Lumps and Fines. Of the two products, lump product yields a 20% return premium per tonne compared to the fines product, due to better performance in upgrading the iron ore to steel in the steel mills. As a result the mining companies look to maximise their lump yield, thus increasing revenue and potential profitability of the operation. The tertiary crusher is the last stage of comminution before the product goes to the customer; therefore the tertiary stage has the largest influence on the particle size distribution of the product. Traditional tertiary crushing circuits comprise of a cone crusher with a vibrating screen in closed circuit to produce the -31.5mm products. However, cone crushers have a tendency to produce fines and as a result there has been extensive work done with screen apertures and gap settings to optimise the crushing stage to maximise lump product yield. In 2007, Sandvik released the ‘Hybrid’ double roll crusher, which is a combination of sizer technology and double roll crusher technology. Prior to the Hybrid, there was not a viable alternate solution to the cone crusher for tertiary stage crushing of competent and abrasive material. The Hybrid was promoted due to the fact: •It can be operated in open circuit •Anecdotally, would produce more lump product than the cone crusher circuit Both the Capital expenditure and the Operating expenditure calculations conducted as part of the study yielded similar totals Simulation testing of the comparative options revealed that; at optimum gap settings (i.e. gap settings that produce highest lump product yield) the Hybrid crusher produced an extra 2.8% lump product yield compared with the Cone crusher. The simulations results provided a case for further field testing. Testing revealed that in fact the Cone crusher circuit yield an additional 6.9% in lump product compared to the Hybrid crushing circuit based on ‘best’ gap setting conditions.
|Translated title of the contribution||Evaluation of a ‘Hybrid’ double roll crusher in DSO Iron Ore tertiary crushing application|
|Publication status||Published - 2016|