Particle synthesis by means of the thermohydrolysis of mineral precursors

A method for continuously preparing mineral particles by thermolysis of mineral precursors in an aqueous medium comprising:

• (a) contacting a reactive flow with a heat transfer flow in a mixing chamber in a countercurrent manner so as to form a mixture flow, the reactive flow and the heat transfer flow being distinct flows, whereby the reactive flow includes mineral precursors selected from the group consisting of hydrosoluble metallic nitrate salts of transition metals, hydrosoluble metallic nitrate salts of lanthanides, hydrosoluble metallic sulfate salts of transition metals, hydrosoluble metallic sulfate salts of lanthanides, bis(ammoniolacto)dihydroxytitanium, hydroxides of transition metals and hydroxides of lanthanides, wherein the mineral precursors in the reactive flow are at a temperature lower than the conversion temperature of the mineral precursors into mineral particles, and the heat transfer flow contains water at a temperature that is sufficient to bring the mineral precursors to a temperature higher than the conversion temperature,
• (b) conveying the mixture flow of step (a) into a tubular reactor;
• and
• (c) forming particles from the mixture flow of step (b) by gradually converting the mineral precursors into particles,
• wherein the mixing chamber is fed by at least two supply pipes,
• wherein the reactive flow is injected into the mixing chamber by at least one of the at least two supply pipes in the mixing chamber and the heat transfer flow is injected into the mixing chamber, countercurrent to the reactive flow, by a third pipe, and
• wherein the mixing chamber has a maximum cross-section larger than the outlet cross-section of each of the at least two supply pipes and the third pipe.