Abstract:
The self-reducing technology for primary metals production presents great potential due to high reduction rate and high energy efficiency. The results should be high productivity and energy saving, contributing to the mitigation of CO2. Two processes are normally used to agglomerate the composite mixtures. One is the cold agglomeration, using cement as binder, which reacts with water forming a gel and after curing consolidates as a continuous phase covering the ore and carbonaceous particles conferring high mechanical strength. The main drawback is that needs a high content of cement, around 6 to 10%, increasing slag volume downstream, and at high temperatures, at 800 to 1000oC, the hydrates formed decomposes and strength goes down. Another process is “self-agglomeration, self-reducing”, that is, the coal of high fluidity is used as reductant and as binders. This type of metallurgical coal, by coking mechanism, consolidates as continuous coke phase after heating giving strength for agglomerates. There is no additional binder, therefore, results on less slag downstream, but it is not a cold agglomeration process. It needs to be heated before (ore and reductant) or after agglomeration to around 500oC or higher temperatures. The objective of this paper is to present the analysis, based on the literature, of possible alternatives of binder for self-reducing agglomerates and present preliminary experimental results.
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