383-389This paper
reports the findings of an investigation of the breakage values of lignite to
relate the wettability properties. The breakage values, obtained from grinding,
are the specific rates of breakage (Si) and the γ of value
the primary breakage function (Bi,J), and the wettability
parameter, which is also easily obtained from contact angle measurements and
flotation tests, is the critical surface tension of wetting value of solid (γc).
The grindings were carried out as dry, wet and wet with kerosene aided tests in
a laboratory size porcelain ball mill. The products (-212 μm) of the feed sizes
of -600+425, -425+300 and -300+212 μm of lignite ground in the mill have been
tested to obtain the γc values by contact angle goniometer and our new designed
micro-flotation column cell. It is proposed that a relationship exists between
the Si and γc value of the lignite sample studied,
i.e .. higher the Si value from the breakage process, lower the γc value in
wetting processes, indicating less wettability in the physical-chemistry based
separation methods. There is also another relatio nship found between the γ
value of Bi,j (the fineness factor) and the γc value,
where γ value increases with increasing γc value, except in the kerosene
aided
grindings. This means, coarser
particles produced by grinding will behave more hydrophilic (i.e., water wets
the solid completely) in the wetting operations.</span