| 摘要 |
<p>A process for producing unsintered agglomerates from dust originating from a product stream of an industrial process involving thermal treatment of materials containing alumina such that the agglomerates are suitable for handling and return to the product stream or an industrial feed stream, and the agglomerates so formed. The process involves binding the dust particles together using rehydratable alumina and water as a binder. If the dust already contains rehydratable alumina (e.g. dust from alumina and bauxite calciners), further rehydratable alumina need not necessarily be added. If the dust contains little or no alumina, a source of rehydratable alumina sould be added to the dust. If the dust contains an alumina hydrate, some or all of the dust may be heated to form rehydratable alumina. The dust and/or added rehydratable alumina may be ground, if desired, to create fresh surfaces and a range of sizes suitable for compaction. In all cases, the resulting solids should have a ratio of dust to rehydratable alumina of 0.5 - 5 : 1 by weight. After mixing the solids with water (usually 2 to 40 parts, more preferably 10 to 35 parts, by weight per 100 parts by weight of solids), the resulting mixture is agglomerated and the agglomerates are preferably aged for up to 24 hours in an atmosphere of high relative humidity in order to strengthen the agglomerates. Optionally, drying and calcining (without sintering) may then be carried out. The resulting dust agglomerates can be handled without significant fracturing or dust generation and can, if desired, be returned to the product stream or to an industrial feed stream.</p> |
