| 摘要 |
<p>In briquetting specular hematite fines, they are heated under reducing conditions to raise their temperature into the range 850-1050 DEG F. and effect a partial reduction of the hematite such that 15% to 30% by weight of the original oxygen content is removed and then there is mixed with the heated and part reduced fines sufficient low temperature bituminous coal fines, which are at ambient temperature or at the temperature resulting from washing and drying such coal fines, to produce a uniformly dispersed mixture containing 5% to 15% by weight of coal and having an apparent temperature as measured before the mixture reaches thermal equilibrium of 600-800 DEG F., which mixture is formed into briquettes whilst at this temperature, the coal serving as a binder and being subsequently cooled, re-oxidation of the hematite being prevented. The reducing step is preferably performed in a fluidized bed, the fluidizing gas being H2, CO, or mixtures thereof at a temperature of 900-1000 DEG F. A fluxing material may be included with the fines in a quantity sufficient to produce a self-fluxing briquette. The briquettes may be cooled in a shaft by a stream of cool-reducing gas which is then used in heating and reducing the hematite. The preferred amount of partial reduction is 18-23% by weight.</p> |
