RARE -- CHAPTER 1 -- MAN AND METAL

CHAPTER 1 – MAN AND METAL

In this first chapter, the author gives an overview of humans’ relationship with metals and what is to come in the rest of the book. He first briefly describes some commonly used metals, their relative amounts and extraction methods to contrast it with the much lower amounts of these rare metals, down to ppb quantities in terms of atom count.  He gives a brief list of the uses of rare metals such as tantalum, rhodium, europium, erbium, etc.   He asks, are these metals rare because there is not a lot of them or is it because they are hard to extract?  He points out humans have only explored the earth’s crust superficially and has discovered a metals distribution that is unequal, favoring one region in high concentrations over another.  This led him to ask the question of whether the limited supply and high demand will eventually lead to more conflicts between nations and between regions within nations.

·         Aluminum, copper, and iron are some of the more well-known, ubiquitously used metals.

·         Another class of metals whose industrial use has steadily increased in the last three decades but has remained fairly lesser known has been used in consumer electronics, health care, communications, and the defense industry.

·         The word metal derives from the Greek word metallon, meaning mine or quarry.

·         The author describes the well-known physical and chemical properties of metals as follows:

o   Have the ability to transmit electricity and heat (very useful in electronics)

o   Most can be bent and molded into intricate shapes

o   Most are resistant to all but the most extreme chemical reactions in the outside environment (rusting of iron is an exception)

·         Quantifying the amount or concentration of metals in the earth’s crust:  Most metals exist in the ppm or even ppb range (atom count) in the earth’s crust (see below).  Its distribution is such that it can be quite concentrated in one geographical region but not found in others.  Many metals are siderophiles, “iron-loving” and thus found whenever there is a considerable deposit of iron.

o   Pt = 4 ppb atoms

o   Ag = 20 ppb atoms

o   Os (osmium), Re (rhenium), Ir (iridium), Ru (ruthenium), Au << 1 ppb atoms

o   Pm (promethium, named after the Greek god Titan Prometheus) is at the extreme end of the scarcity spectrum.  It was first isolated in 1963 and only a little over a pound (latest estimate is 586 g) is expected to exist in the earth’s crust.  If available in sufficient amount, it is useful for powering decades-long effective atomic batteries, the book claims.

·         Siderophiles:  osmium, gold, platinum, and palladium are four of the 12 metals.  Their siderophilic nature might be the reason these metals don’t exist in large amounts in the earth’s crust.  The earth’s core is estimated to be 90% iron [by mass or volume?].  Theoretically, there should be more of these metals but they are simply hard to find and extract.

·         The earth’s mass is approximately 6 x 10²⁴kg. 

o   Hydrogen, oxygen, aluminum, and iron make up about 90% of the earth’s crust. 

o   Silicon, nickel, magnesium, sulfur, and calcium about 95 of the earth’s crust. 

o   The rest of the elements make up the last 1%.

·         Deposits of gold and other rare metals are often found conjugated to sulfur near hydrothermal vents.

·         Kola Superdeep Borehole:  This Russian project began in 1970 and continued for the next two decades.  A total depth of 12 km was reached before the project was abandoned; machinery was breaking down as the temperature increased about 15 F every 1.5 km reaching 200 F at the farthest depth reached by the digging instrument.  This depth represents only about a third of the crust’s estimated thickness.  The goal of the project was to see how deep humans can dig below the surface and to study the make-up of the outer layer of the earth’s crust.

·         Current technologies make aluminum fairly easy to find, extract, and recycle.  Copper, on the other hand, is abundant but not easy to extract from the crust in pure form.  The author points out that, for our ancestors, bronze (alloy of tin and copper) had sufficient properties to make weapons and tools out of but our current industrial uses of copper require a more pure form.

·         Extraction process for copper: 

o   Copper is found bound in the mineral chalcopyrite. 

o   Chalcopyrite is crushed and smelted.

o    The sulfur (a gaseous infusion) is removed.

o   The resulting solution is subjected to electrolysis to extract 99% pure, usable copper.

·         Aluminum used to undergo a similar process until a less work-intensive method was developed by Charles Martin Hall in 1886.  This caused the price of aluminum to drop significantly.  Hall became president of one of the largest aluminum producers in the world.

·         Extraction of gold:  The process to extract pure gold is actually relatively simpler, “Bronze Age technology” according to the author.  Gold is already relatively pure [chemically stable element] when found and requiring little processing.  The first step is to melt samples at a temperature just below 2000 C in container resistant at these high temperatures (e.g. ceramic or charcoal-based).  Boric acid is added to keep everything else solid while the gold melts.  The pure liquid can then be poured after the solid contaminants are skimmed off the surface.

·         Tantalum replaced aluminum as a capacitor “in order to keep up with processor demands”.  It is also found in almost every smartphone.  Tantalum used be the conducting filaments in light bulbs but now has been replaced by tungsten.

·         Rhodium, ruthenium, palladium, tellurium, rhenium, osmium, and iridium are rare metals that have found uses in the medical industry.

·         Platinum (Pt), palladium (Pd), and rhodium (Rh) are used in catalytic converters.

·         Europium (Eu) is used to provide the red color in liquid crystal displays.

·         Erbium (Er) is used for coating fiber optic cable to “increase the efficiency and speed of information transfer”.

·         Neodymium (Nd) has permanent magnetic properties useful in headphones, speakers, microphones, hard drives, and electric batteries.

·         In this section titled WILL SUPPLY + DEMAND = CONFLICT, the author brings up some of the complex issues arising from control of limited supply, high-demand materials like these rare metals.  He sums it up in this way: “These relatively unknown but now essential metals are gathered from concentrated deposits in remote areas.  Since the use of metal combines the principles of finite resources with the necessity of costly expeditions and retrieval processes, an immediate upsurge in demand often leads to the upheaval of lives across the world.”