A new concept in catalytic coal gasification has been developed. The use of crude vinegars (CVs) derived from different lignocellulosic biomass resources is described for the recovery and reuse of calcium in coal gasification. Calcium introduced by impregnation with a CV solution produced a higher catalytic activity than calcium loaded by impregnation with an aqueous acetic acid solution. Furthermore, CVs were found to be capable of reclaiming calcium from gasification residue and of improving the catalytic activity of the indigenous crystalline calcite in bituminous coal as in situ catalyst. (c) 2009 Elsevier Ltd. All rights reserved.