Microwave Energy for Expanding Perlite Ore

 

J. A. Aguilar-Garib*^1,2, V. García-Onofre¹, U. Ortiz^1,2, Zarel Valdez-Nava¹

 

¹ Facultad de Ingeniería Mecánica y Eléctrica Universidad Autónoma de Nuevo León San Nicolás de los Garza, NL, México. *juan.aguilargb@uanl.edu.mx.

² Centro de Investigación, Innovación y Desarrollo en Ciencia y Tecnología Universidad Autónoma de Nuevo León, Apodaca, NL, México.

 

ABSTRACT

Perlite is an igneous mineral composed by silicon, aluminum, oxygen and water. It can be expanded by heating it up at temperatures above 870 °C, then it becomes plastic, and the steam formed inside pressures out of the mineral. Maximum expansion is possible if the particles are heated up quickly, since the expansion degree strongly depends on the remaining water in the particles at the time that they reach the temperature where they become plastic. The typical expansion process consist in pouring the particles in rotary kilns operated with natural gas, but it is proposed in this research that the particles can be heated quickly with microwaves at 2.45 GHz. Particles of 0.08 cm and 0.018 cm of average diameter were expanded 10 to 20 times.

Keywords: Microwaves, perlite, expansion, heating.

 

RESUMEN

La perlita es un mineral ígneo compuesto de silicio, aluminio, oxígeno y agua. Se puede expander si se le calienta a más de 870 °C, entonces se vuelve plástica, y el vapor que se forma en el interior de las partículas de perlita presiona al mineral hacia afuera causando su expansión. La expansión máxima es posible cuando las partículas de perlita se calientan rápidamente, dado que el grado de expansión depende fuertemente de la cantidad de agua que aun esté presente en las partículas al momento que éstas alcanzan la temperatura en que se vuelven plásticas. El proceso de expansión típico consiste en vaciar las partículas en hornos rotatorios que operan con gas natural, pero en esta investigación se propone que las partículas pueden ser calentadas rápidamente con microondas de 2.45 GHz. Las partículas de perlita de 0.08 cm y de 0.018 cm de diámetro promedio se expandieron 10 a 20 veces.

 

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