Patent ID: 7829598

Claim:
A synthesis method for producing a nano-sized material, said nano-sized material is produced in a semi-continuous or continuous mode, comprising the steps of: pressurising a first fluid, and heating said first fluid to a temperature above its critical temperature pressurising a second fluid, and heating said second fluid comprising at least one precursor and/or reactant to a second temperature below the first temperature and below the thermal decomposition temperature of said precursor(s) and/or reactant(s), and controlling the mixing of the first fluid and the second fluid in a first mixing zone so as to provide a fluid mixture at a temperature causing a conversion of said precursors and/or reactants into a nano-sized material with predefined characteristics, while the fluid is in the mixing zone maintaining said fluid mixture at said temperature in a predefined reaction time, cooling said fluid mixture to a temperature below 100° C., expanding said fluid mixture in one or more step/-s, wherein the zeta potential of said fluid mixture is controlled so that the zeta potential of said fluid mixture comprising said nano-material is in the range −20 mV to −65 mV or in the range of 20 mV to 65 mV so as to keep the produced material suspended in the fluid mixture, the controlling of the zeta potential of the mixed fluid is performed by controlling the pH value of said fluid mixture by addition of acid and/or base and/or is controlled by the controlling the concentration of electrolytes present in said fluid mixture, the ratio of the average velocity of the fluids upstream of said first mixing zone to the average velocity in said first mixing zone (v/v mix ) is at least 8.