Wash Ability Curves

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<p>Determination and use of washability curves</p> <p>SACPS Vryheid Golf Club 24 May 2006</p> <p>Washability curves1. Principles 2. Sampling 3. Float &amp; Sink 4. Analysis 5. Calculation 6. Plotting of washability curves 7. Use of washability curves</p> <p>Sampling Standard prescribes minimum of 1000 particles per size fraction and minimum 10 particles per relative density fraction</p> <p> Approximate formula: Sample mass ~ 5 x Average particle size</p> <p>Sampling: Minimum sample massNominal size (mm) - 125 + 63 - 63 + 31.5 - 31.5 + 16 -16 + 8 -8+4 -4+2 - 2 + 0.5 - 0.5AS 1661-1979 (Figures valid for raw coal)</p> <p>Minimum mass (kg) 400 100 25 7 3 1.5 1.0 0.5</p> <p>Float &amp; Sink analysisTypical heavy liquids used in laboratory: Zinc Chloride Bromoform TBE (Tetra Bromo Ethane)</p> <p>Float &amp; Sink tank</p> <p>Float &amp; Sink analysis : Procedure1. Make up correct densities in series of containers (test with hydrometer) 2. Place sample in container (start at lowest or highest rd depending on sample) 3. Remove floats, remove sinks 4. Remove dense liquids from floats and sinks filtering and/or washing 5. Dry samples 6. Weigh and analyse samples 7. Calculate washability and plot curves</p> <p>Washability curves: Uses1. Design of coal processing plants 2. Techno-economic evaluations 3. Reserve estimation 4. Plant efficiency testing 5. Day-to-day plant control</p> <p>Near-dense material% of material within +0,10 and -0,10 interval at any specific density</p> <p>Washability Analysis :</p> <p>No. 5 Seam</p> <p>Fractional Rel.Dens. Yield F@ F@ F@ F@ F@ F@ F@ F@ F@ F@ F@ F@ F@ F@ F@ S@ 1.30 1.35 1.40 1.45 1.50 1.55 1.60 1.65 1.70 1.75 1.80 1.85 1.90 1.95 2.00 2.00 16.4 15.5 3.9 3.3 1.1 1.0 0.8 1.0 1.2 1.0 1.0 0.4 0.4 1.0 0.9 51.1 Ash 4.1 7.0 13.1 19.3 23.2 31.2 34.9 40.1 42.9 47.8 49.7 51.6 51.8 61.1 69.7 76.9</p> <p>Cumulative Yield 16.4 31.9 35.8 39.1 40.2 41.2 42.0 43.0 44.2 45.2 46.2 46.6 47.0 48.0 48.9 100.0 Ash 4.1 5.5 6.3 7.4 7.9 8.4 8.9 9.7 10.6 11.4 12.2 12.6 12.9 13.9 14.9 46.6</p> <p>Washability Analysis :</p> <p>No. 2 Seam</p> <p>Fractional Rel.Dens. Yield F@ F@ F@ F@ F@ F@ F@ F@ F@ F@ F@ F@ F@ F@ F@ S@ 1.30 1.35 1.40 1.45 1.50 1.55 1.60 1.65 1.70 1.75 1.80 1.85 1.90 1.95 2.00 2.00 9.88 15.71 16.65 13.72 10.49 7.47 5.66 3.66 2.77 2.46 2.85 1.19 0.5 0.8 0.5 5.7 Ash 4.9 6.9 9.7 14.8 18.8 22.9 29.0 36.6 40.6 45.3 48.9 51.4 53.3 57.9 63.9 79.1</p> <p>Cumulative Yield 9.88 25.59 42.24 55.96 66.45 73.92 79.58 83.24 86.01 88.47 91.32 92.51 93.00 93.80 94.32 100.00 Ash 4.9 6.1 7.5 9.3 10.8 12.0 13.2 14.3 15.1 16.0 17.0 17.4 17.6 18.0 18.2 21.7</p> <p>False middling</p> <p>Coal</p> <p>Shale</p> <p>Liberation by crushing</p> <p>Coal Shale</p> <p>Washability data - Dolan Colliery100.0 90.0 80.0</p> <p>Cumulative Yield %</p> <p>70.0 60.0 50.0 40.0 30.0 20.0 10.0 0.0 0.0 5.0 10.0 15.0 20.0 25.0 30.0</p> <p>Cumulative Ash %Coarse Small</p> <p>Washability data - Dolan Colliery100.0 90.0 80.0</p> <p>Cumulative Yield %</p> <p>70.0 60.0 50.0 40.0 30.0 20.0 10.0 0.0 0.0 5.0 10.0 15.0 20.0 25.0 30.0</p> <p>Cumulative Ash %Coarse Small</p> <p>Washability data - Dolan Colliery100.0 90.0 80.0</p> <p>Cumulative Yield %</p> <p>70.0 60.0 50.0 40.0 30.0 20.0 10.0 0.0 0.0 5.0 10.0 15.0 20.0 25.0 30.0</p> <p>Cumulative Ash %Coarse Small</p> <p>Plant Efficiency Acceptance test Routine checks</p> <p>Plant Efficiency1. Test procedure &amp; sampling 2. Interpretation of results 1. Ash balance method to determine yield 2. Plotting of Tromp (Partition) curve 3. EPM,Organic Efficiency, Misplaced material</p> <p>Plant Efficiency1. Samples taken of feed, product (floats) and discards (sinks) 2. Sample mass as per standard (~ 5 x ave particle size) 3. Number of increments = 32 (raw coal feed), 16 washed coal (product &amp; discard) 4. Determine ash content of feed, washability analysis of product and discard</p> <p>Plant Efficiency TestingFeed</p> <p>Product</p> <p>Discard</p> <p>Plant Efficiency TestingFeed</p> <p>32 increments Ash content Product</p> <p>Discard</p> <p>Plant Efficiency TestingFeed</p> <p>16 increments</p> <p>Product Washability analysis</p> <p>Discard</p> <p>Plant Efficiency TestingFeed</p> <p>Product</p> <p>16 increments</p> <p>Discard</p> <p>Washability analysis</p> <p>Plant Efficiency(discard ash feed ash)</p> <p>Ash balance:</p> <p>% Yield = -----------------------------------</p> <p>x 100</p> <p>(discard ash product ash)</p> <p>Calculation of partition curve Plotting of curve</p> <p>Plant EfficiencyOrganic efficiency = actual yield at actual ash content /theoretical yield at actual ash content x 100</p> <p>Plant EfficiencyOrganic efficiency = actual yield at actual ash content /theoretical yield at actual ash content x 100 example: Actual yield = 61,44 % (from ash balance) Theoretical yield = 61,63 % (from reconstituted feed washability) -&gt; Organic efficiency = 61,44/61,63*100 = 99,7 %</p>