Characterizing the Materials Composition and Recovery Potential from Waste Mobile Phones
Last edited Mon Oct 8, 2018, 01:31 PM - Edit history (1)
The paper from the primary scientific literature that I will discuss today, is represented, in part, by the title of this post. The full title is:
Characterizing the Materials Composition and Recovery Potential from Waste Mobile Phones: A Comparative Evaluation of Cellular and Smart Phones (Singh et al ACS Sustainable Chem. Eng., 2018, 6 (10), pp 13016–13024.
Recently I drove up to my son's university - which is not far - to bring him the replacement cell phone his mother bought him in case the one he had finally failed; he jumped in a swimming pool with it just weeks after his brother jumped in the ocean with his. We were able to actually get the swimming pool version to work, by putting it under high vacuum after soaking it in deionized water. The same procedure did not work for the ocean water exposed cell phone.
The technicians at the store cheerfully switched the phones over.
Since I have an acute awareness of what's in their phone - I often get myself in a "peak oil tizzy" over indium, even if "peak oilism" has entirely lost credibility because it didn't happen fast enough to make sense in our party hearty and screw tomorrow world. (I personally can't wait for "peak oil," since I'm not so concerned that the oil will run out but that the place to dump oil waste - the planetary atmosphere and hydrosphere - has run out of space to safely contain it.
I asked the technician who was working on my phone if he could "recycle it" and he just laughed, since, he said he has no idea how to do that, and when he has a customer who insists he try, he usually ends up putting the phone in the trash.
Recycling is energy intensive, and depending on how its done, can have huge environmental, health and moral problems. Toxicology literature examining China is rife with these consequences.
However, with vast quantities of cheap, clean energy I believe it's possible and desirable.
The paper cited at the beginning here does a wonderful job telling us what's in cell phones.
First it's always good to begin with scale; too often our lies to ourselves begin with representing some lab scale thing as if it were an industrial solution. The scale of cell phones, according to the part I've put in bold from the introductory text is mind boggling.
A mobile phone is a portable hand-held device that can make and receive calls over a radio frequency link within a telephone service area. A mobile phone that contains a fixed set of functions such as voice calling, text messaging, and web browsing is generally referred to as a feature or cellular phone; a mobile phone that contains a number of distinguishing features and offers greatly advanced computing capabilities is referred to as a smart phone.(5) The volume of waste mobile phones is growing rapidly all over the world, while the collection and recycling rates of these waste devices are insignificant compared to other waste electrical appliances.(3,6?8) Waste mobile phones typically consist of many materials such as plastic, printed circuit boards (PCBs, which contain most of the precious and toxic metals), screens, magnets, vibrators, LED back lights, steel, and batteries, with a complex chemical composition.(9) In the past few years, various researchers and research institutions have published numerous research studies, white papers, and reports on the metal composition of mobile phones.(6,10?14) However, no comprehensive evaluation of the precise components of these devices, nor any comparative study of the various models of cellular and smart phones and their metal compositions, is readily available.
The authors note that a lot of precious materials go into making these devices, reporting data indicating that the world's electronics industry consumes more than 850 metric tons of gold, 6500 tons of silver and almost 30 tons of palladium annually.
Gold mining, in particular, is a very noxious business: think mercury, or cyanide or both.
Anyway, the authors provide us with a wonderful graphic showing where the stuff in portable phones are located:
Not all of these materials are found in "green" solar cells, by the way, but many are, which is why - speaking only for myself - I have a jaundiced view of the words "green" and "renewable" attached to solar cells. They require far more mass than cell phones and for that matter computers, meaning that their scale will dwarf the already intractable electronic waste scale.
By the way PCB here does not refer to the highly toxic polychlorinated biphenyls, but rather to "printed circuit boards" (Many electronic devices do contain PBDE's - polybrominated diphenylethers - as flame retardants. Measurements have been made showing huge concentrations of this stuff in Chinese children; China's banning imported "green" electronic components to be recycled.
This graphic, similar to the first, adds metal content to the components.
The caption:
The grind the cell phones up to analyze them:
Here's where he finds the metals are:
The caption:
The mass of precious metals in cell phones.
The caption:
Figure 5. Precious metal content in waste cellular and smart phones’ PCBs, manufactured between 2001 and 2015. (a) Precious metal content in waste cell phones. (b) Precious metal content in waste smart phones.
While these gold mg/phone concentrations seem low, keep in mind that ores from which gold is mine - again using very dirty processes - are also at a similar level of concentration.
The authors comment:
The demand for precious metals such as gold, silver, and palladium has been increasing rapidly with the increasing consumption in the electronics industry around the world. Figure 6(a) and (b) show the precious metal consumption trends in waste cellular and smart phones from 2001 to 2015. These results reveal that the consumption of precious metals has been constantly increasing in smart phones, while in cellular phones the contents of gold and palladium have remained almost unchanged while the silver content has shown a rapidly increasing trend. The average price trends of the precious metals from 2000 to 2017 are shown in Figure 6(c) (data attached in Supporting Information Table S2). This figure shows that the prices of all the precious metals are increasing, although gold and silver reached their peaks in 2012 and then resumed normal trends in 2013, possibly because of the global economic recession or the gold mining restrictions in some countries. Nevertheless, overall price trends are increasing along with the increasing demand for precious metals in metal-consuming industries. For example, approximately 861 tonnes of gold, 6619 tonnes of silver, and 29 tonnes of palladium are being consumed by the electronic industries annually.(18) However, these amounts of precious metals represent only 10 to 15% of total global production, while the recovery rate for these precious metals from all end-of-life electronic devices is less than 10%, and in the case of mobile phones, it is around 2 to 5%, and sometimes even less. Most of the precious metals in waste mobile phones are still encased somewhere in individual households or storage yards
They produce another graphic relevant to their discussion:
The caption:
The authors conclude in part:
It is high time for waste mobile phones to get proper attention from government and the public, to increase awareness about their recycling value and the hazardous toxins they create when improperly managed. Not only are there serious environmental and human health effects from improper management waste mobile phones, but recycling the phones also has real economic value.(48,49)
What they say here probably goes for other electronic waste, but note it is more expensive, and energy intensive, to do this safely as opposed to declaring ourselves "green" because "we" "recycle" without regard to the conditions and health of the impoverished people who make us "green."
I have to go.
Have a pleasant work week.
