The invention relates to a process for preparing lower olefins from an oxygenate, the process comprising: subjecting C4 hydrocarbons obtained in an oxygenate-to-olefins conversion step to extractive distillation to an etherification step to convert isobutene into an alkyl tertiary butyl ether to obtain an isobutene-depleted C4 hydrocarbon stream and alkyl tertiary-butyl ether; subjecting the isobutene-depleted C4 hydrocarbon stream to extractive distillation to obtain a stream enriched in unsaturated C4 hydrocarbons and a stream enriched in saturated C4 hydrocarbons; and recycling at least part of the stream enriched in unsaturated C4 hydrocarbons and/or at least part of the alkyl tertiary-butyl ether to the oxygenate-to-olefins conversion step.