The Past, Present, and Future of Mineral Processing, Hydrometallurgy, and Pyrometallurgy

The Past, Present, and Future of

a) Mineral Processing,

b) Hydrometallurgy,

c) Pyrometallurgy.

Rather than asking you to do a team project at the end of this coming semester, as in Pre-COVID -19 times, we will instead continue with the successful individual essay, power-point presentations, that we changed to, during our remote delivery of MIME250. The headline topic “The past, present, and future, of mineral processing, hydrometallurgy, and pyrometallurgy”, from that time, will allow you to discuss and evaluate among yourselves the trends in Extractive Metallurgy from a local, and world point view. You should consider examples taken from various extractive processes that will have to be changed, given the future need to achieve neutral carbon by 2050 announced by the United Nations Council on global warming. Meanwhile, all peoples of this world are hoping to achieve the same standards of living as those in the G7/G20 countries! This will require future metal production to increase, and these include new metals (e.g. Li, Co, etc.), as well as “old” metals (Fe, Al, Cu, Zn, etc.). Evidently the two imperatives of CO2 reduction versus CO2 production from oxide reductions, etc., are on a collision course unless we make radical changes in our processing methods.

In choosing your essay topic from a list of proposed topics presented below, or an alternative we approve of, you can use the knowledge gained from our course work lectures, to learn of the way in which Extractive Metallurgy processes have developed over the years, and how they will have to be changed, and are changing, in the coming years. This is a global imperative, given our contributions to CO2 accumulations in the atmosphere, amount to about 12% of the total anthropomorphic contributions of CO2 deemed responsible for global warming. Unfortunately, given the problems of widely different methods of government, of wealth distribution, and national aspirations, the outcome will be very “dodgy” in achieving carbon neutrality, within the 2050AD time frame. This is definitely a challenging essay topic, but it should be fun, and you can dig your teeth into it. You should make use of the internet for your research needs, as well as our lecture notes.

So, you are asked to prepare individual essays, of about 1500 words, on some topic dealing with the anticipated changes in extractive metallurgy processes.

We suggest that you all try to devote 20% to Min.Pro., 40% to Hydro., and 40% to Pyro., if appropriate. Do a classic essay, but split into the three parts, concerning Mineral Processing, Hydrometallurgy, and Pyrometallurgy.

Background Information

As background information, you will learn that our mineral needs have grown rapidly over the last 150 years. Prof. Hassani, of our Mining Department, kindly agreed to set the scene, in our first lecture, re the world’s mining industry.  He was then followed in subsequent weeks by a series of lectures on Mineral Processing, and now on Extractive Metallurgy. This component has been broken down into two parts; hydrometallurgy, and pyrometallurgy.

Over the past sixty years, our world seems to have been experiencing increasingly severe climate events. Practically all good engineers and scientists believe that these events are anthropomorphic (i.e. man-made) in origin. These changes in climate, “global warming”, have been fueled by the burning of carbon containing materials to supply us with heating, or power, or by using these carbon-containing materials to chemically reduce metal oxides, down to their required metal elements.

Of course, we are very fortunate, in that we have built a series of hydro-electric dams, such as James Bay, that provides us with a wealth of hydro-electric power. After all, Canada enjoys about 40% of the total world’s fresh water supplies! This Hydro-power is available for our personal use, in heating our homes, or fueling our electric vehicles, or providing us with well-lit streets at night, air-conditioning in the summer, etc.. As such, Quebec should have no problem meeting the required emission standards in the future. However, over and above these applications, Quebec has enough electrical power being generated, at competitive prices, to allow many major metal companies to select Quebec for locating their energy-intensive factories. Here, they use “harmless” hydro-electricity, but still “have to use” carbon, in the carbothermic reduction of most metal oxides, to metals, even in Quebec.

For instance, near the town of Contrecoeur, just down river from Montreal, an ArcelorMittal Long products Plant (formerly a Stelco steelplant), re-melts steel scrap in circular Electric Arc Furnaces. Similarly, a little further downstream, at Trois Rivieres, RTIT-QIT uses electricity to reduce ilmenite (FeO.TiO2) to a titania rich slag (TiO2) in ten large rectangular Electric Arc Furnaces with anthracitic coal. It then reduces the unreduced, but now carbon-saturated, molten iron, in two Electric Arc Furnaces, to produce steel billets and blooms, for further processing. Also close to Trois-Rivieres, in Becancour, three huge Electric Furnaces (2x 24MW, and 1x 32MW) heat and reduce pure silica ore, also with anthracitic coal and wood chips, to produce liquid ferro-silicon, or silicon. Formerly an SKW plant, it is now owned by Dow-Corning (49%). Again, adjacent to this, is an Alcoa Aluminium manufacturing plant, Aluminiere Becancour, producing liquid aluminium at the cathode, and CO2 at the anode, in a highly electrically demanding fashion, using pre-baked, carbon anodes! A little further along the St Lawrence, on the left side of the estuary, we reach the Sagueney river, which empties its fresh waters into the tidal region of the St Lawrence. If we travel up the Sagueney river, it leads us up to Arvida and Chicoutimi, where ALCAN (now Rio Tinto Aluminum) has many such aluminum plant operations. Again, these use hydroelectric power from their hydro-dam at the end of Lac St Jean, producing liquid aluminum by the energy-intensive Hall-Heroult Process.

Extractive Metallurgy Processes

Unfortunately, all these operations rely on carbon, to strip the oxygen from the metal oxides, thereby creating GHG’s (Greenhouse Gases), which lead to global warming. So, with respect to the past and present of metals production, we have all been firmly entrenched in using carbon to reduce oxygen from many of the metal oxides, one way, or another. Similarly, pyrometallurgy involves the use of high temperatures, often using heat sources that are carbon based. For the future, we must seek processes that do not contribute to creating Greenhouse Gases. We see that burning carbon containing materials such as coal, coke, charcoal, natural gas, with air, while creating heat and steam(energy) to power electric turbines, is also creating carbon dioxide! As such, they are increasing the anthropomorphic outputs of GHG’s, leading to global increases in average temperatures, since the CO2 takes a very much longer time frame, to be re-absorbed into rocks. So, even Quebec, a major user of green hydroelectricity, is not out of the woods, given its choice to sell its excess hydroelectricity cheaply to metal producers and polluters!

So, in closing, extractive metallurgists need to develop alternate ways to those that lead to GHG emissions, in extracting our metals from the various ore bodies where they are combined with other elements in the earth’s crust. So, enjoy researching possible ways forward, for humanity!

Examples of possible topics you may like to consider/choose. The list is by no means exclusive. Check with the Profs, re your selections, if you need any advice.

1. Alternative methods for producing steel, using electricity
2. Alternative methods for producing steel, using hydrogen
3. The hydrogen car for clean commuting. An alternative to EV’s?
4. The pros and cons of light-weighting cars; past, present, and future.
5. The development of the Lithium battery, vs the Lead Acid Battery, for transportation. 
6. The future for molten metal batteries for energy storage and release at household/village/city level requirements.
7. Environmental considerations regarding of existing Hydrometallurgical Processes.
8. Implications and the Recycling of materials for a circular economy.
9. The possible development of Electric powered aircraft vs currently fueled jet engines.
10. Ironmaking Blast Furnace technologies, using carbon sequestration to eliminate CO2 emissions to the atmosphere? Costs and Reliability issues.
11. Hydrogen reduction of iron oxides, producing water vapor
12. An all-molten metal battery system for variable electrical energy storage when using variable inputs from Solar and Wind Farm sources.
13. The revision of the Hall-Heroult Process for producing molten aluminium, using inert anodes, vs Carbon anodes; advantages and implications for the environment.
14. The panning for gold? Nature’s example of a mineral processing operation?
15. The production of gold at CCR (Canadian Copper Refineries) Its input source and economic benefits?
16. Plasma Technologies for extractive metallurgy (pyro-metallurgy) processes.
17. The possibility of a hydrogen-based energy economy for metal extraction systems
18. Nuclear fusion for extractive metallurgists.
19. The elimination of the cabon
20. Mining asteroids for Fe and Ni?
21. Examples of water contamination from Hydrometallurgical plants, and methods to mitigate these.