Plotting washability curve of coal based on origin7.5

Washability curve is a basis on which coal quality analysis and design of coal preparation plant can be well performed, therefore, it is quite important to plot washability curve correctly with simple method.

Description is done by way of actual exsamples, of the method in which the EXCEL function is used to plot raw coal washability curve.

Based on the fundamental forms of HR washability curves,plot steps of coal slime flotability curves introduced;according to the results of coal slime regressive release flotation test,separately plotted the curve of:concentrate β,tailing θ,ash characteristics λ,yield γ,concentrate ash ±0.

Present coal washability evaluation method and its weakness are introduced in this paper And the knowledge and character of coal washability based on coal petrography are also summarized The expert system can be used as coal washability evaluation and research method

In addition,different equations denoting the selectivity curves are summarized,including normal,log normal,skew normal,gamma and bimodal distribution.

According to the theory of maximum likelihood method of gillnet selectivity that rose in resent years, this paper uses the Normal,Gamma and Lognormal selectivity models, which are commonly used to describe gillnet selectivity curve, to analyze the catch data of Nemipterus virgatus from simultaneous fishing with 45,50,55 and 60 mm mesh sizes of gillnets in 1992.