Quality Process Solutions
Coal Preparation and Mineral Processing Solutions
Fines Processing
Classifying
The size based classification of fine particulate material can impact the efficiency of a number of downstream processes. The accurate tracking of performance, identification of key performance indicators, adjustment of set points and sizing of equipment components all contribute to ensuring the efficiency of the classification process.
In plants which do not beneficiate ultra-fines, the performance of a classifying cyclone cluster directly impacts on plant yield. For example, for a 1000 t/h CPP with 20% reporting to the desliming screen underflow, 5% of material misplaced to the cyclone overflow can be 10 t/h. This material then directly reports to tailings. At an assumed fines yield of 60% and a sale price of $100/t, this translates to a nominal revenue loss of $4.26 million per year for a 7100 h/annum CPP.
Fines Beneficiation
Fines beneficiation processes are relatively minor components of CPPs compared with dense medium processes; however the inherently lower separation efficiencies and improved liberation of the fines fraction mean that significant variation of revenue results from inconsistencies in the operation of this equipment. The performance of equipment such as spirals, Reflux Classifiers (RC) and Teetered Bed Separators (TBS) can be tracked by sampling and analysis of feed and product streams, in the same manner as dense medium cyclones or baths. This data can be analysed and used to identify and assess the impact of problems as they occur.
Assessing the impact of yield losses on a 1000 t/h plant (with 10% reporting to the fines beneficiation circuit) shows that 5% misplaced material to reject gives a 5 t/h loss of product and a subsequent $3.55 million revenue loss per year for a 7100 h/annum CPP assuming a coal price of $100/tonne.
In addition to yield loss due to inefficient fines separation, beneficiation processes are susceptible to increases in product ash due to inappropriate set points or worn and damaged equipment. Increased fines product ash typically requires a commensurate decrease in coarse product ash with a resulting overall plant yield loss.
QPS Services
QPS can analyse and interpret sample data consequently identifying problems through review of data and site visits QPS can then formulate solutions to improve yield and selectivity.
QPS staff have experience in the operation, optimisation and troubleshooting of cyclones, spirals and teetered bed separators and so can suggest any required equipment replacements, changes in set points or circuit modifications to would improve the operation of a fines processing circuit.