A reactive precipitation/crystallization reactor, comprising an outer tubular element and an inner tubular element, coaxial with respect to the outer tubular element along a longitudinal axis of the reactor to form, between an outer wall of the inner tubular element and an inner wall of the outer tubular element, an annular channel, wherein the outer tubular element comprises, at a first end, at least one inlet opening for a first reactive fluid and, at a second end, an outlet opening for a reaction mixture, and wherein the inner tubular element comprises an inlet opening for a second reactive fluid, wherein, the inner tubular element comprises, along the outer surface thereof, a plurality of dispensing openings for dispensing said second reactive fluid fed into the inner tubular element;
- wherein dispensing nozzles are associated with the dispensing openings;
- and
- wherein the dispensing nozzles comprise a channel having a first section with a first diameter and a second section with a second diameter smaller than the first diameter, wherein said second section comprises a fluid dispensing hole, in which said dispensing hole has a diameter between 0.1 and 5 mm.