Original scientific paper

Wettability of Coal Surface and its Surface Free Energy Components

Bronislaw Janczuk ; Department of Physical Chemistry, Institute of Chemistry, Maria Curie-Sklodowska University, 20-031 Lubin, Poland
Wieslaw Wojcik ; Department of Physical Chemistry, Institute of Chemistry, Maria Curie-Sklodowska University, 20-031 Lubin, Poland
Tomasz Bialopiotrowicz ; Department of Physical Chemistry, Institute of Chemistry, Maria Curie-Sklodowska University, 20-031 Lubin, Poland

Abstract

Contact angles were measured for various coal ranks - water
drop - n-hexane, n-dodecane and cis-decalin systems. Using the'
results obtained the values of the dispersion and nondispersion
comnonents of the surface free energy of Polish coal of various
ranks, from 31.1 to 35, were calculated. These values (Ysđ and YsP)
were compared with those calculated on the basis of measurements
of contact anzles conducted earlier for various coal ranks - air
bubble or hvdrocarbons dron - water systems. The results obtained
allowed us to conclude that, firstlv, the surface free energy
of coals results from both the dispersion and nondispersion intermolecular interactions and secondlv, that disnersion components
of this energy depend on the coal ranks. The value of nondispersion
components of the surf'ace free enegzv does not depend on the
coal ranks and should not exceed 10 mJ/m2. It was also found that taking into account the values of dispersion components of the studied coals surface free energy we can classify them into three grups: 1) coal rank 31, 2) coal rank32 and 3) coal rank 33, 34 and 35.

Keywords

Hrčak ID:

175870

URI

https://hrcak.srce.hr/175870

Publication date:

28.4.1988.

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