The invention provides a process for the preparation an emulsion of elemental sulphur particles, said process comprising the steps of: (a) providing a first stream comprising a liquid fertilizer and/or a liquid fertilizer precursor; (b) providing a second stream comprising liquid elemental sulphur; and (c) mixing the first stream and the second stream in a mixing device in the presence of a multifunctional ionic surfactant to form an emulsion comprising elemental sulphur particles which are coated with a layer of the multifunctional ionic surfactant and dispersed in the fertilizer and/or the fertilizer precursor, whereby a temperature is applied which maintains the elemental sulphur substantially in the liquid form in the mixing device. The invention further provides an elemental sulphur-containing fertilizer obtainable by a process according to the invention.