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Date of Award

2019

Document Type

Campus Access Dissertation

Degree Name

Doctor of Philosophy in Chemical Engineering (PhD)

Administrative Home Department

Department of Chemical Engineering

Advisor 1

Timothy C. Eisele

Committee Member 1

Lei Pan

Committee Member 2

Caryn Heldt

Committee Member 3

Bowen Li

Abstract

With the depletion of high-grade and low phosphorus iron ore reserves, the extensive goethite ores containing high phosphorus become more attractive. However, there is a lack of effective and economic technologies for removing phosphorus from goethite ore. The current utilization of goethite ore to date has been to, first reducing the phosphorus to low of a level as practical by mineral processing, and blend it with other low-P iron ores along with other feed material (e.g. coke and fluxes) to balance out the overall phosphorus level in blast furnace. Therefore, the market share of goethite is largely limited owing to lack of effective and economical technology for phosphorus removal. Roasting at ≥ 900 °C followed by dilute acid leaching route has been reported to be very effective in removing phosphorus from goethite ore by various researchers in the past. However, the main flaws of this process were the need for high temperature roasting, the consumption of un-recyclable acids, and lime requirement for neutralization of the leach solution afterwards. The main objective of this dissertation was to find a more technically efficient and cost - effective way to remove phosphorus from goethite ore. We focused on studying of the dephosphorization of goethite ore through low-temperature (85 - 300°C) alkaline leaching or roasting approaches. As an alternative, the possibility of phosphorus extraction by bio-leaching method was also investigated. It has shown that temperature and the concentration of hydroxyl ions play the major roles in the alkaline approaches in terms of phosphorus removal. By incorporating a liquor regeneration process, it was shown that the low-temperature alkaline process can be satisfactory in both dephosphorization and cost-effectiveness making a potentially viable process in the industrial application. Bio-leaching, on the other hand, did show some phosphorus extraction, and more importantly, it would extend the knowledge of bio-dephosphorization and therefore build a basic foundation for future study.

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