The ferrite process is an established method for treating wastewaters containing dissolved toxic metals, using precipitation at temperatures above 65°C. Various ambient-temperature operation methodologies have also been proposed, but the effects of temperature reduction on product stability, and on the extent of isomorphous substitution (in terms of x in Me x Fe 3−x O 4 , Me representing a non-iron metal), have not been adequately quantified. At ambient temperature precipitation, maximal x of Zn 2+ , Co 2+ , Ni 2+ and Cd 2+ was found in the current study to be approximately 0.73, 0.67, 0.39 and 0.17, respectively. These values are 73% to 50% of the corresponding values attained by precipitation at 90°C. The chemical stability of the ferrites produced under ambient temperatures was found to deteriorate upon high Me 2+ incorporation levels, in stark contrast with the trend observed in ferrites precipitated at 90°C. Both observations were ascribed to the increased importance of Fe 2+ –Fe 3+ interaction under ambient conditions in driving spinel ordering. In the presence of high Me to Fe ratio in the initial solution, this interaction is weaker, resulting in impeded dehydration.