Resumen
Process for the production of magnetic cork particles, particles thus obtained and uses thereof. The present invention relates to a process for producing magnetic cork particles comprising the steps of providing a composition of an alkaline solution and cork particles, with a size comprised between 1 nm and 2 mm, and stirring; add an acid solution containing Fe3 + and Fe2 + cations to the composition to cause the magnetization of the cork particles and maintain agitation; filter the obtained solution to obtain a precipitate of magnetized cork particles and wash the precipitate with water until the washing solution reaches a pH comprised between 4 and 7, and allow to dry until obtaining stabilized magnetized cork particles, in which the magnetization of the cork particles is due to the formation of a magnetite coating on the particles, the magnetite adsorbing on the surface of the particle. It also refers to magnetized cork particles thus obtained and their uses. (Machine-translation by Google Translate, not legally binding)
Reivindicaciones
1. A method for producing magnetic cork particles, the method comprising the steps of: a) Providing a composition comprising an alkaline solution containing cork particles, said particles with a size comprised between 1 nm and 2 mm and stirring; b) Adding an acid solution containing Fe<3+> and Fe<2+> cations to the composition obtained in a) to cause the magnetization of the cork particles and maintaining the stirring; c) Filtering the solution obtained in b) to obtain a magnetized cork particles precipitate, and d) Washing the precipitate with water until the washed solution reaches a pH comprised between 4 and 7 and let dry until obtaining stabilized magnetized cork particles, wherein the magnetization of the cork particles in b) is due to the formation of a magnetite coating on the particles, being the magnetite adsorbed on the particle surface. 2. Method according to claim 1, wherein the alkaline solution of step a) is NaOH or NH<3>. 3. Method according to claims 1 or 2, wherein the acid solution has a pH between 1.5 and 2.5. 4. Method according to claim 3, wherein the acid solution of step b), containing Fe<3+> and Fe<2+> cations, is obtained from chloride salts or ferric or ferrous sulphates. 5. Method according to any of claims 1-4 wherein the Fe<3+>/Fe<2+> cations keep a ratio of 5/3 molar. 6. The method according to any of previous claims, wherein the cork particles are subjected to a surface pre-treatment prior to step a). 7. The method according to claim 6, wherein the pre-treatment is a cleaning or surface activation treatment. 8. The method according to claim 7, wherein the pre-treatment includes washing the cork particles with deionized water, acetone and ethanol, and let them dry. 9. The method according to claim 7, wherein the pre-treatment includes treating and cleaning cork particles in a low pressure plasma chamber with a gas. 10. Magnetised cork particles obtained by the method according to claims 1-9. 11. Use of magnetised cork particles, according to claim 10, in the manufacture of adhesive or paint compositions. 12. Use according to claim 11, wherein the magnetised cork particles are between 0,01 and 40% of the total composition volume. 13. Use of magnetised cork particles, according to claim 10, in the manufacture of polymer matrix composites. 14. Use according to claim 13, wherein the magnetised cork particles are between 0,01 and 70% of the total composition volume of the composite. 15. Use of magnetised cork particles, according to claim 10, in the manufacture of small magnetic particles. 16. Use according to claim 15 wherein the small magnetic particles are sensors, relays or electromagnets.
