A coal gasification operation or similar conversion process is carried out in the presence of an alkali metal-containing catalyst producing char particles containing alkali metal residues. Alkali metal constituents are recovered from the particles by burning the particles to increase their size and density and then leaching the particles of increased size and density with water, to extract the water-soluble alkali metal constituents.

An auto-ranging ac resistance measuring instrument for remote measurement of the resistance of an electrical device or circuit connected to the instrument includes a signal generator which generates an ac excitation signal for application to a load, including the device and the transmission line, a monitoring circuit which provides a digitally encoded signal representing the voltage across the load, and a microprocessor which operates under program control to provide an auto-ranging function by which range resistance is connected in circuit with the load to limit the load voltage to an acceptable range for the instrument, and an auto-compensating function by which compensating capacitance is connected in shunt with the range resistance to compensate for the effects of line capacitance.