| 摘要 |
A process for the oxidation of powder materials containing starch, which comprises the successive steps of mixing a powder material comprising starch with an aqueous solution of hydrogen peroxide (H2O2) and adding to the mixture thus obtained an aqueous solution of ammonia and reacting it with said mixture; the process may also comprise a further step of drying the aforementioned mixture to obtain a powder material containing oxidized starch; the process may advantageously comprise the steps of: - feeding a continuous flow of powder material containing starch into a first reactor (R) comprising a cylindrical tubular body (1) and a rotor, arranged in the cylindrical tubular body, comprising a shaft (8) provided with elements (9) projecting radially therefrom and rotated at a speed greater than or equal to 50 rpm, - feeding into said reactor also a continuous flow of an aqueous solution of hydrogen peroxide - reacting the powder material containing starch and the hydrogen peroxide; - discharging from a discharge opening (7) of the first reactor a continuous flow of a wet powder and feeding this continuous flow into a second reactor (R') comprising a cylindrical tubular body (101) and a rotor, arranged in the cylindrical tubular body, comprising a shaft (108) provided with elements (109) projecting radially therefrom and rotated at a speed greater than or equal to 50 rpm; - feeding into the second reactor (R') also a continuous flow of an aqueous solution of ammonia, - discharging from a discharge opening (107) of the second reactor a continuous flow of a wet powder comprising oxidized starch; - drying the wet powder to a moisture content less than or equal to 20% by weight, thereby obtaining a powder material containing oxidized starch. |
