The synthesis of an effective composite fuel from industrial wastes almost always requires mixing several components with different properties. Features of certain components can effectively compensate for the limitations of others, eventually improving the fuel as whole. We propose the optimization of the waste-derived coal-water slurry (CWS) by doping it with a small amount (2-5 wt%) of non-hydrocarbon dopants (metal-bearing powders with aluminium, iron, copper and chalk). It allows the stabilization of the combustion temperature (or even its increase), while keeping the ignition delays at the reasonable level (similar to 2 s at 1000 K). Doping the CWS by 2-5 wt% of chalk powder allows a radical decrease in the production of harmful exhausts (up to an order of magnitude regarding the SO2 and 2-5 times regarding NOx). A strong ecological effect was observed when the fuel is doped by iron powder, too. Therefore, the usage of non-organic dopants is a very promising way to prepare environmentally friendly fuel compositions with high power efficiency. (C) 2018 The Combustion Institute. Published by Elsevier Inc. All rights reserved.