An ash fusion temperature reducing agent comprising a comminuted ore mixture of the silicates of iron, calcium, magnesium and aluminum is mixed with an ash containing pumpable liquid hydrocarbonaceous material to produce Mixture A. Mixture A is reacted with a free-oxygen containing gas in a partial oxidation gas generator. A hot raw effluent gas stream comprising H.sub.2 +CO along with molten ash having a reduced ash fusion temperature are produced at a lower temperature. Alternatively, Mixture A may be first introduced into a coking zone and converted into petroleum coke in which the ash fusion temperature reducing agent is dispersed throughout. The petroleum coke is then introduced into the partial oxidation gas generator where the hot raw effluent gas stream comprising H.sub.2 +CO is produced along with molten petroleum coke ash having a reduced ash fusion temperature. The molten ash is readily separated from the effluent gas stream and the gas generator may be operated at a lower temperature thereby extending the life of the refractory lined reaction zone.