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The purpose of the master's work
The purpose of this work is the research of the most accurate methods of the determination of coal-preparation factory technological scheme work expected operation factors by means of comparing calculation results and actual data received from work of the concrete preparation factory for further usage of these methods in practice to make the most profit.
The practical value
The practical value of this work consists of possibility of using work results at real preparation factory for the most accurate determination technological scheme work operation factors as a result that factory may make profit lost in waste production output.
Review of the existed works
Berd's method
The essence of the method is that decisive factor determined coal's suitability for preparation, is material quantity, contained in determined limits higher and lower of the accepted coal separation density for structure components. Deflection limits from separation density Berd accepted based on the experimental data are equal ±100 kg/m3. For example, if the separation density is equal 1500 kg/m3 then it's necessary to determine material quantity, contained in density limits 1400-1600 kg/m3. If one coal contains this fraction 5%, and other coal - 15%, then the first coal will be preparated easier than the second one. In this case free rock (with density more than 2000 kg/m3) Berd excluded from examination.
Figure 1 - Berd's curve built with graphic way:
1 - middle concentrate's densities curve β; 2 - elementary ashes curve λ; 3 - middle waste's densities curve θ; 4 - Berd's curve; 5 - densities curve δ.
Toporkov's method
For the estimation coal's suitability for preparation Toporkov proposed the next formula:
T = 100 γ/β B,
where γ - theoretical concentrate yield when the density is 1500 kg/m3 in percents from raw coal; β - theoretical concentrate ash when density is 1500 kg/m3; B - coal's fraction yield which the density is 1800 kg/m3 in percents from raw coal.
Toporkov gives the next scale of the estimation coal's suitability for preparation based on his formula:
| Preparation suitability index | Difficulty degree |
| More then 20 | High (easy) 1 |
| 20-16 | High (easy) 2 |
| 16-14 | Middle 1 |
| 14-12 | Middle 2 |
| 12-10 | Low (difficult) 1 |
| 10-8 | Low (difficult) 2 |
| 8-7 | Low (difficult) 3 |
| 7-6 | Very low 1 |
| 6-5 | Very low 2 |
| Less then 5 | Exceptionally low |
Fomenko's method
Suitability for preparation by Fomenko is characterized by elementary ashes curve of researching coal λ or the coefficient of suitability for preparation K; the coal density (curve λ) when separation is the most profitable; concentrate yield when in coal separation density is the most profitable.
The curve λ enough accurate is characterized by sag arrow f, i.e. by distance on normal from the most farther point of curve λ (curve's summit) to straight line which expresses ideal difficult coal's suitability for preparation. The sag arrow size relation to it maximum possible size (for curve which express ideal easy suitability for preparation) is named as the coefficient of suitability for preparation or the index of suitability for preparation K (Fig. 2):
K = f / F
Figure 2 - Diagram for determination the most profitable coals separation regime by Fomenko
Mayer's method
In 1950 Mayer proposed the curve which expresses middle value of coal's suitability for preparation. M-curve is obtained by summation area which is closed by the base Anry's curve λ (Fig. 3). On the abscissa axis is lain aside quantity of ash units (multiplication floated fraction yield to ash content in it), and on the ordinates axis yield of fractions.
By Mayer's curve is possible to come to the conclusion about the coal's suitability for preparation. When Mayer's curve curvature radius is lower then the coal's suitability for preparation is easier, and, on the contrary, with the increase curvature radius separation difficulty increases.
Figure 3 - Mayer's curve of suitability for preparation
Geraschenko's method
Based on the statistical treatment of the large quantity of fraction analysis's of the Donetsk coals results were obtained expressions for description curves λ and β. The design of these curves is realized on three parts corresponding to set fractions. Each curve's part is described expression itself.
Elementary ashes curve λ is described by equations system:
AI = Amin + a1γn;
AII = b0 + b1γ + b2γ k;
AIII = c0 + c1γ + c2γ2.
If light fractions are picked out by density 1500 kg/m3 we have:
Àmin = 0,7 + 0,29 À<1500
Parameters a1, b0, b1, b2, c0, c1, c2, n, k are determined from the limited conditions, i.e. from the equality final and initial ashes on parts.
Equations system describe the curve β:
where γ1 and γ2 - yield of light and intermediate fractions in raw coal.
Conclusion
In the result of our work it will be possible to give recommendations to enterprises about usage of the most accurate and acceptable method of the determination of expected operation factors of work for their calculation on the practice. As a usage result of this method a factory may make more profit than obtained before it. That is the most important result of this work.
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