Questions Flashcards
(1) What is the definition of “sustainable development”? Why is the term “sustainability” often preferred over the term “sustainable development”?
(2) What is biomimicry? What are the main principles on which biomimicry is based? Give three examples of how biomimicry can help to decrease the carbon footprint of our society.
(3) The 12 Principles of Green Chemistry and the 12 Principles of Green Engineering are well known guidelines for making the chemical industry more sustainable. So far no “12 Principles of Green Metallurgy” (or “12 Principles of Sustainable Metallurgy”) have been formulated. Make a suggestion for such a list of 12 principles.
(4) How can green engineering help to enable a circular economy in the electronics industry?
(5) It is a paradox that precisely those persons who are very environmentally conscious and strive for a rapid transition to a low-carbon economy may endanger the supply of the raw materials needed for this transition because of their protests against the opening of new mines. Discuss this paradox and provide a possible solution for this problem.
Chapter 2: 53-57
(6) The 1972 report of the Club of Rome (published in the book “ The Limits to growth: a global challenge “) was very negative about the future availability of raw materials. For example, it was predicted that by the year 2000 the copper resources would be largely depleted. However, the predictions about resource scarcity all proved to be wrong. Why were the authors of this report completely wrong with their predictions?
(7) Show that the criticality of raw materials has little to do with the availability of these raw materials in the earth’s crust. What are the disadvantages of using a list of critical raw materials as a policy instrument?
(8) Why does is make sense, from the point of view of sustainability, to convince materials engineers to develop new materials with an as low as possible content of by-product metals?
(9) Platinum-group metals (PGMs) and rare-earth elements (REEs) may be considered as “coupled elements”. (a) What does the term “coupled elements” mean? (b) What is the difference between coupled elements and by-product elements?
(10) One often reads in the popular press that metal recycling via urban mining can replace the primary mining of metal ores. Is this a realistic approach and why (not)?
(11) How can rare-earth elements help to reduce the reduction CO2 emission from burning of fossil fuels?
(12) What are the options for end-of-life product in (a) a linear economy and (b) a circular economy?
(13) What are the benefits and limitations of recycling?
(14) What are the different steps in a generic flow sheet for recycling of materials? What are the least and most efficient steps in this flow sheet? Why?
(15) (a) Why does it not make sense, from the point of view of energy consumption, to try get a recycling rate of 100% for metals from end-of-life products? (b) Why have iron, copper, aluminium, lead, platinum-group metals, gold and silver high recycling rates (>50%), whereas the recycling rates for the rare-earth elements are very low (<5%)?
(16) Why do have many metals very low recycling rates, although recycling is technologically feasible? How can legislative initiatives help to increase recycling rates?
(17) What are the differences between metal-centric recycling and product-centric recycling? Which of the two approaches is the preferred one and why?
(18) It is a general trend in the history of technology that materials are becoming more and more complex in terms of the total number of chemical elements used in materials. Is this a positive trend in terms of sustainability? Why (not)? Discuss this statement.
(19) The process flowsheet of steel-making from iron ores is quite different from that for recycling of steel scrap. Discuss the main differences. Why are different processes used for steel-making from iron ores and from steel scrap?
Today there are two major commercial processes for making steel, namely basic oxygen steelmaking, which has liquid pig-iron from the blast furnace and scrap steel as the main feed materials, and electric arc furnace (EAF) steelmaking, which uses scrap steel or direct reduced iron (DRI) as the main feed materials. Oxygen steelmaking is fueled predominantly by the exothermic nature of the reactions inside the vessel; in contrast, in EAF steelmaking, electrical energy is used to melt the solid scrap and/or DRI materials. In recent times, EAF steelmaking technology has evolved closer to oxygen steelmaking as more chemical energy is introduced into the process.[2]
(20) How can platinum-group metals (PGMs) be recycled from automobile catalysts?
(21) What rare-earth elements are present in fluorescent lamp phosphor waste and how can these be recycled?
(22) What is enhanced landfill mining (ELFM)? What are the differences between urban solid waste landfills and industrial residue monolandfills? Why is it so difficult to make an economic success story of ELFM?
- Industrial process residues are ubiquitous in EU
- A multitude of these residues has been historically stored in monolandfills and/or tailing ponds
- Large-scale ELFM (and recycling) of these landfilled (and fresh) residues is not happening yet
- Commercialisation dependent on 4 key parameters:
– Volume (substantial and guaranteed access)
– Performance (in product replacement terms)
– Cost (a strong economic case must exist)
– Risk (needs to be well understood and offer a lower risk than storage over the same time frame)
• Economics can be improved if zero-waste concept can be applied (avoidance of (re)landfill costs), incl. higher added-value applications: – Recovery of critical metals (e.g. Sc from bauxite residue)
– Recovery of base metals
– Recovery of mineral matrices for construction applications
• Major, concerted R&D efforts are required to:
– Develop new metallurgical systems for eco-friendly flow sheets
– Produce outputs with high quality standards at low cost
• Adequate policies that promote use of secondary resources (EC CE Action Plan – EC COM(2015)614/2)
(23) What different waste-to-energy technologies can be used in enhanced landfill mining (ELFM)?
(24) The process residues of the metallurgical industry could be a valuable source of critical metals and base metals. However, it is recommended to use a product-centric approach rather than a metal-centric approach for valorization of these residues. Why? What are the most interesting industrial residues for metal recovery? How are they formed and what metals are present at high concentrations in these residues?
(25) Compare the advantages and disadvantages of homogeneous and heterogeneous catalysts.
(26) What is fluid cracking catalysis (FCC) and what types of catalyst is used for this process?
(27) Which pollutants are emitted by incomplete combustion of hydrocarbon fuel? What are the health and environmental issues related to these pollutants?
(28) What is the function of a catalytic converter in cars? Describe a catalytic converter from a materials point of view (geometry, structure, chemical composition, function of materials).
(29) Describe the working principle of a three-way catalyst for exhaust after-treatment of spark-ignition engines operated under stoichiometric conditions.
(30) What is the role of oxygen storage by ceria in a three-way catalyst? Why is ceria able to store and release oxygen?
(31) What is the role of precious metals in three-way catalysis?
(32) Why is diesel catalytic exhaust after-treatment more complicated to gasoline engines? What catalysts are present in the exhaust after-treatment system of a diesel vehicle?
read SCR catalyst (last page)
(33) Discuss selective catalytic reduction (SCR) with ammonia in the exhaust after-treatment system of a diesel vehicle.
(34) Discuss the working principle of Li-ion batteries.
(35) What are the advantages and disadvantage of the different types of cathode materials presently used in these batteries?
(36) Discuss the working principle of redox flow batteries. Why could this type of batteries be of importance in the future to secure the electricity supply in Belgium?
(37) Discuss the advantages and disadvantages of the following types of solar cells: (1) monocrystalline silicon solar cells, (2) polycrystalline silicon solar cells, (3) thin-film solar cells.
(38) What are the most promising elements for the design of post-Li ion batteries? What are the advantages and disadvantages of these elements in possible battery application?
(40) Compare the application fields of different types of batteries: (a) lead-acid batteries, (b) nickel metal hydride batteries, (c) Li-ion batteries, (d) redox flow batteries.
