| 摘要 |
<p>A process for producing particles of magnesium spinel (magnesium aluminate) suitable for reinforcing metal matrix composites. The process involves mixing a waste material containing alumina or a precursor, such as dross residue, ESP dust or offgrade or contaminated alumina from Bayer process plants or molten salt electrolysis factories, with magnesium oxide or a precursor to produce a mixture, calcining the mixture at a temperature suitable to produce magnesium spinel (usually between 1450 and 1650 °C), and collecting particles of the magnesium spinel having a size in the range of 5-50 νm, if necessary after comminuting larger particles to sizes in the desired range. Preferably, particle growth promoters may be added to the starting materials, examples being metal oxides and fluorides generally used in amounts of about 1-2 % by weight. The resulting inexpensive particles have a size suitable for metal matrix reinforcement and are substantially unreactive with molten aluminum and aluminum alloys.</p> |
