cobalt news · 2019-10-02 · including additive manufacturing, aerospace, automotive, batteries,...

Promoting the responsible use of cobalt in all forms

COBALT NEWS

Promoting the sustainable and responsible use of cobalt in all forms

Issue 4, October 2018

METALYSIS BEGINS PRODUCTION

WITH FIRST INDUSTRIAL-SCALE

METAL POWDER PLANT

CAN COBALT CHANGE THE

ENVIRONMENTAL IMPACT OF

MANUFACTURING?

MODERN ALCHEMISTS ARE

MAKING CHEMISTRY

GREENER

HISTORICAL SERIES: COBALT IN

ANCIENT GLASS

COMMENT

2 | www.cobaltinstitute.org

The year is almost at an end and cobalt contin-

ues to be in the market’s limelight as one of the

most sought after elements, primarily due, but

not only, to being an essential component of re-

chargeable batteries which have become a

burning topic both for industries and consumers

concerned about a wide range of goods from

digital and electronic devices (smartphones, lap-

tops and various types of appliances) to electric

vehicles.

Oddly enough, you will remember our editorial

from the same period last year where we

stressed the pressure that EU regulators were

applied on cobalt. Well, nothing has changed so

far and cobalt remains under heavy scrutiny with

different regulatory proposals being submitted

simultaneously (Metal CLH, cobalt salts Re-

striction, RoHs etc). There is a need for a more

balanced regulatory framework to provide the

planning security for industry to produce and

use cobalt substances in the EU. Hopefully it is

not too late to appreciate that cobalt is a tech-

nology enabling material currently irreplaceable

in most of the applications where it is used to-

day.

We are inaugurating a new section of the Cobalt

News in this issue, the Historical Series, in which

to find out articles from the Cobalt Institute ar-

chive that provide information about the curious

world of cobalt’s.


2 Comment

4 Metalysis begins production

with first industrial -scale

metal powder plant

6 Catalyst advance could lead

to economical fuel cells

8 Methane to syngas catalyst:

two for the price of one

10 Can cobalt change the envi-

ronmental impact of manu-

facturing?

16 Modern alchemists are

making chemistry greener

20 Historical Series: Cobalt in

ancient glass

CONTENTS


Metalysis’ Generation4 industrial plant (Courtesy Metalysis Ltd.)

Metalysis Ltd., Rotheram, South Yorkshire, UK,

has launched its first commercial metal alloy

powder production plant at its facility in Wath

upon Dearne, South Yorkshire, UK. The Gener-

ation 4 (Gen4) project was mechanically com-

pleted in Q4 2017 and has since undergone

hot commissioning, trial runs and optimisation.

The handover from testing to operation signi-

fies Metalysis’ transition into commercial pro-

duction, following more than a decade of

phased technology development.

Gen4 is the first facility to take Metalysis’ solid-

state, modular, electrochemical process to in-

dustrial scale is said to be able to produce tens

-to-hundreds of tonnes per annum of high

value, niche and master alloys. The facility cre-

ates a new source of supply for global end-

users in advanced manufacturing disciplines

including Additive Manufacturing, aerospace,

automotive, batteries, light-weighting, magnets

and mining.

One of the reported benefits of Metalysis’

technology is its multi-metal capability, which

enables the company to produce alloy ‘recipes’

that comparable processing routes cannot.

Where conventional technologies are unable to

combine elements with melting and density

differentials, this technology can because it is a

solid-state process. It is said to enable Metaly-

sis to commercially produce a demand-driven

product mix of titanium alloys, master alloys

including Scandium-Aluminide, compositionally

complex alloys including high entropy alloys,

magnet materials, high temperature materials

and platinum group alloys.

METALYSIS BEGINS PRODUCTION WITH FIRST INDUSTRIAL-SCALE METAL POWDER PLANT


The modularity of the technology is said to of-

fer further benefits, such as its ability to offer a

wide range of order quantities. Throughout

phased expansions, the technology has also

presented opportunities to reduce all-in costs

and environmental footprints compared to tra-

ditional

melting production routes.

“In powering up and operating our industrial

plant, Metalysis is poised to achieve its target to

generate significant profits from our new South

Yorkshire production facility,” stated Dr Dion

Vaughan, Chief Executive Officer, Metalysis.

“Ours is a true British success story with inter-

national implications. Metalysis has grown from

the ‘lightbulb moment’ at Cambridge University

in the late-1990s, relocated to South Yorkshire

to benefit from regional excellence in opera-

tional skillsets in the early-2000s, and now on-

wards towards a bright commercial future.”

“In powering up and operating our

industrial plant, Metalysis is poised

to achieve its target to generate

significant profits from our new

South Yorkshire production facility”

“Ours is a true British success story with inter-

national implications. Metalysis has grown from

the ‘lightbulb moment’ at Cambridge University

in the late-1990s, relocated to South Yorkshire

to benefit from regional excellence in opera-

tional skillsets in the early-2000s, and now on-

wards towards a bright commercial future.”

In March 2018, the company announced that it

had raised £12 million to fund state-of-the-art

post-processing facilities, feedstock and pro-

vide working capital to support the roll-out of

Gen4.

Overall, approximately £25 million has been

raised to fund the project to completion.

(This article was posted on Metal Am on 6 September

2018)

SCALE

http://www.metal-am.com/metalysis-begins-production-with-first-industrial-scale-metal-powder-plant/


Researchers at Washington State University

have developed a new way to make low-cost,

single-atom catalysts for fuel cells -- an ad-

vance that could make important clean energy

technology more economically viable.

Hydrogen fuel cells are critical for the clean

energy economy as they are more than two

times as efficient at creating electricity than

polluting combustion engines. Their only

waste product is water.

However, the high price of the platinum-based

catalysts that are used for the chemical reac-

tion in fuel cells significantly hinders their

commercialization.

Instead of the rare platinum, researchers

would like to use nonprecious metals, such as

iron or cobalt. But reactions with these abun-

dantly available metals tend to stop working

after a short time.

CATALYST ADVANCE COULD LEAD TO ECONOMICAL FUEL CELLS


"Low-cost catalysts with high activity and stability are critical for the com-

mercialization of the fuel cells" said Qiurong Shi, postdoctoral researcher in

the School of Mechanical and Materials Engineering (MME) and a co-first

author on the paper.

Recently, researchers have developed single-atom catalysts that work as

well in the laboratory setting as using precious metals. The researchers

have been able to improve the stability and activity of the nonprecious

metals by working with them at the nanoscale as single-atom catalysts.

In this new work, the WSU research team, led by Yuehe Lin, an MME pro-

fessor, used iron or cobalt salts and the small molecule glucosamine as

precursors in a straightforward high temperature process to create the sin-

gle-atom catalysts. The process can significantly lower the cost of the cata-

lysts and could be easily scaled up for production.

The iron-carbon catalysts they developed were more stable than commer-

cial platinum

catalysts. They also maintained good activity and didn't become contami-

nated, which is often a problem with common metals.

"This process has many advantages," said Chengzhou Zhu, a first author on

the paper who developed the high temperature process. "It makes large-

scale production feasible, and it allows us to increase the number and

boost the reactivity of active sites on the catalyst."

Lin's group collaborated on the project with Scott Beckman, an MME associate professor at WSU, as

well as with researchers at Advanced Photon Source at Argonne National Laboratory and

Brookhaven National Laboratory for materials characterization.

"The advanced materials characterization user facility at the national laboratories revealed the single-

atom sites and active moieties of the catalysts, which led to the better design of the catalysts," said

Lin.

Original publication: Chengzhou Zhu et al.; "Hierarchically Porous M–N–C (M = Co and Fe) Single-

Atom Electrocatalysts with Robust MNx Active Moieties Enable Enhanced ORR Performance"; Ad-

vanced Energy Materials; 2018.

(This article was posted on CHEMEUROPE on 4 September 2018)

http://www.chemeurope.com/en/news/1157205/catalyst-advance-could-lead-to-economical-fuel-cells.html


METHANE TO SYNGAS

CATALYST:

TWO

FOR THE PRICE OF ONE


Hokkaido University researchers have created an improved catalyst for the conversion

of methane gas into syngas, a precursor for liquid fuels and fundamental chemicals.

Syngas, also known as synthesis gas, is a mixture made primarily of carbon monoxide

and hydrogen and is used to manufacture polymers, pharmaceuticals, and synthetic pe-

troleum. It is made by exposing methane to water vapor at 900 °C or higher, making

the process costly.

The partial oxidation of methane for syngas synthesis is more economical than using

steam but there have been issues with the catalysts used for this process. Noble metal

catalysts, such as rhodium and platinum, are better and work at lower temperatures

than base metal catalysts, such as cobalt and nickel, but they are also more expensive.

The cheaper base metal catalysts require temperatures above 800 °C, exceeding the

temperature range for industrial stainless steel reactors. They are also deactivated dur-

ing the reaction by re-oxidation and the accumulation of coke, a by-product of the

process, making them costly in the long-term.

Assistant Professor Hirokazu Kobayashi, Professor Atsushi Fukuoka, and postdoctoral

fellow Yuhui Hou, working in Hokkaido University’s Institute for Catalysis, succeeded in

preparing a catalyst that combines the properties of both noble and base metals. Their

catalyst overcomes challenges faced by previous studies in adding a small enough

amount of noble metal to the base metal catalyst that it can still work at lower tempera-

tures.

In the study published in Communications Chemistry, the team successfully generated

tiny particles of the base metal cobalt by dispersing them onto a mineral deposit called

zeolite. They then added a minute amount of noble metal rhodium atoms onto the co-

balt particles.

The proposed mechanism in which the hydrogen atoms spill over onto zeolite support,

which then turns the cobalt oxide back into cobalt, keeping the catalyst active. (Yuhui

Hou et al., Communications Chemistry, August 1, 2018).

The new, combined catalyst successfully converted 86% of methane to syngas at 650°C

while maintaining its activity for at least 50 hours.

METHANE TO SYNGAS

FOR THE PRICE OF ONE


Relatively simple chemical processes take

place in our cells, every second. They occur

to help build new proteins, break down

foods for energy (or store the same energy

for later) and to signal between and within

cells. These events involve reactions such as

hydrogenation, which is the addition of H

atoms to molecules.

Industrial chemistry also finds these reactions

useful. While cells use abundant elements

such as carbon to complete these processes

easily and efficiently, chemists haven't been

so lucky!

The materials these groups need to use to

bind hydrogen to the desired molecules (e.g.,

catalysts) are much more unwieldy and al-

most jerry-rigged compared to natural bio-

chemical processes. This may be because

cells have had millions of years to perfect

their reactions, and humans have had only a

few hundred at best!

The reaction oxidizes cobalt to cobalt oxide, which

is nearly inactive. But because the rhodium is con-

tained, the noble metal generates hydrogen atoms

from methane or hydrogen molecules. The hydro-

gen atoms spill over onto the supporting material,

and the spillover hydrogen turns the cobalt oxide

back into cobalt. The cobalt can then continue to

act as a catalyst. The high dispersion of cobalt on

zeolite also prevented the formation of coke dur-

ing the reaction.

Methane has drawn attention as a source of clean

energy as it produces only a half amount of CO2

compared to petroleum when burned. Moreover,

increased shale gas mining has made methane a

more accessible resource. “Our catalyst can effi-

ciently convert methane to syngas at

650°C, a much lower temperature than in conven-

tional methods. This could lead to more efficient

use of methane and contribute to the develop-

ment of a low-carbon society,” says Hirokazu Ko-

bayashi.

Source: Hokkaido University, press release, 2018-

09-05.

Supplier Hokkaido University

(This article was posted on BIO-BASED NEWS on

11 September 2018)

Impact Of Manufacturing?


The Downsides of Traditional Industrial Ma-

terials

Industrial reactants come with disadvantages.

They are often sourced from rare or expensive

sources because they have needed to be very

stable under mass- or precision-manufacturing

conditions. Therefore, popular catalysts include

atoms of rare metals, as they are large and have

the right properties (e.g., electron flow). Howev-

er, finding and mining these materials are an

environmental disaster, especially as these met-

als, like rhodium or platinum, get even scarcer.

These factors may also drive their prices up over

time.

Nevertheless, metals such as these have been

the best option in the synthesis of complex

chemicals (most often drugs) as they can facili-

tate accurate and finely-detailed catalytic steps

in these processes. This kind of chemistry is

called single-electron chemistry, and it is neces-

sary to produce drugs of high-quality to use on

humans.

Single-handedness, or the production of mole-

cules with only one chiral center (e.g., one that

extends to the left or the right), is an important

aspect. Drug molecules of the wrong chirality

may cause severe side effects, which have re-

sulted in toxicity, defects at birth and deaths in

the past. This could be the reason why the phar-

maceutical industry is unwilling to move away

from conventional, rare metal-dependent syn-

thesis.

Cobalt Could be the Future of Industrial Cata-

lysts

Now, there is an emerging option that may rep-

resent a robust alternative to rare-metal use in

synthetic chemistry. Surprisingly, it revolves

around the common transition metal, cobalt.

Classically, cobalt cannot be used in industrial

processes without very specific conditions, such

as in super-dry environments. This is because

Can Cobalt Change The

Environmental

Impact Of Manufacturing?


researchers believed that the metal was a sen-

sitive and fragile catalyst, which could not func-

tion, in single-electron chemistry, in more vari-

able conditions.

However, recent discoveries and adaptations

have demonstrated that cobalt is effective in

certain solvents, more so, ones that rare earth

metals cannot tolerate.

The prime example of these solvents is metha-

nol, which is also an abundant industrial mate-

rial and, therefore, easy and inexpensive to

source.

A team from Princeton University,

led by Professor Paul Chirik, have

demonstrated that it is possible to

make cobalt act like a much more

expensive catalyst, under certain

conditions.

Their new process to make this possible also

involved the reduction of cobalt(2) atom to co-

balt(1) variant, by binding it to a custom-made

p h o s p h i n e ( 1 , 2 - b i s [ ( 2 R , 5 R ) - 2 , 5 -

diphenylphospholano]ethane}) in a reaction

facilitated by zinc in methanol. The resulting

catalyst was then capable of the precise asym-

metrical hydrogenation required to convert a

basic alkene into a real drug molecule.

The group of researchers claimed that the use

of their new Co-catalyst resulted in the pro-

duction of up to 200 grams of the epilepsy

drug, etiracetam.

The catalyst was also highly enantioselective, in

other words, produced only left-handed mole-

cules of the drug.

Other examples of single-electron Co chemis-

try include oxidation using cobalt(3) carbazole

complexes and reduction in the presence of

tetradentate Schiff bases. In addition, this oxi-

dation may be tunable, making it even more

applicable and versatile in relation to synthetic

chemistry.

Other recent studies have demonstrated that

Co is also useful in multi-electron chemistry

and that single-electron chemistry involving

other common elements (e.g., nickel) may be

useful in the treatment of contaminated water.

Can Cobalt Replace Rare Metals?

This new breakthrough - termed by some as

'green industrial chemistry’ - may sound like

excellent news for those involved in the manu-

facture of drugs and other complex molecules.

However, the reality may be more complicated.


Companies routinely put a lot of money into pa-

tenting (or buying the patents of) conventional

catalytic processes that use rare metals. There-

fore, any drive towards replacing them with

newer solutions may meet with some resistance

from these powerful bodies, as well as those

who profit from the supply of rare elements.

On the other hand, Chirik group’s work was

done in collaboration with chemists from the

Merck conglomerate. Therefore, some industry

leaders may be ready to accept a future without

production, resulting in profound environmental

impacts.

The results of this project have also been re-

ported in an article published in a recent issue of

Science.

These findings may open the door

to many other professionals who

are investigating the possibility of

transforming cobalt, or other similar

common transition elements, into

the industrial catalysts of the future.

It appears that the future will be one in which

large-scale chemical manufacturing will not

need to slow down in the face of dwindling re-

sources.

References

Modern alchemists are making chemistry green-

er, 2018, Princeton News, https://

www.princeton.edu/news/2018/06/14/modern-

alchemists-are-making-chemistry-greener ,

(accessed 19 Jun. 18)

M. R. Friedfeld, et al. (2018) Cobalt-catalyzed

asymmetric hydrogenation of enamides enabled

by single-electron reduction. Science. 360:

(6391). pp.888-893.

R. Matheu, et al. (2018) The Behavior of the Ru-

bda Water Oxidation Catalysts at Low Oxidation

States. Chemistry.

M. S. Bennington, et al. (2017) Tuneable reversi-

ble redox of cobalt(iii) carbazole complexes.

Dalton Trans. 46:(14). pp.4696-4710.

J. Andrez, et al. (2017) Ligand and Metal Based

Multielectron Redox Chemistry of Cobalt Sup-

ported by Tetradentate Schiff Bases. J Am Chem

Soc. 139:(25). pp.8628-8638.

Y. Yao, et al. (2018) Activation of persulfates by

catalytic nickel nanoparticles supported on N-

doped carbon nanofibers for degradation of or-

ganic pollutants in water. J Colloid InterfaceSci.

529: pp.100-110.

(This article was posted on EVOLVING-SCIENCE on 11

June 2018)

https://www.evolving-science.com/environment/cobalt-change-environmental-impact-manufacturing-00697

THE COBALT

CONFERENCE

2019 Hong Kong, 15-16 May

Discover more

about it: www.cobaltinstitute.org

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MODERN

ALCHEMISTS

ARE

MAKING

CHEMISTRY

GREENER

Ancient alchemists tried to turn lead and

other common metals into gold and plati-

num. Modern chemists in Paul Chirik's lab

at Princeton are transforming reactions

that have depended on environmentally

unfriendly precious metals, finding cheap-

er and greener alternatives to replace

platinum, rhodium and other precious

metals in drug production and other reac-

tions.

They have found a revolutionary approach

that uses cobalt and methanol to produce

an epilepsy drug that previously required

rhodium and dichloromethane, a toxic

solvent. Their new reaction works faster

and more cheaply, and it likely has a much

smaller environmental impact, said Chirik,

the Edwards S. Sanford Professor of

Chemistry. "This highlights an important

principle in green chemistry -- that the

more environmental solution can also be

the preferred one chemically," he said. The

research was published in the journal Sci-

ence on May 25.

The more environmental

solution can also be the

preferred one chemically

"Pharmaceutical discovery and process

involve all sorts of exotic elements," Chirik

said. "We started this program maybe 10

years ago, and it was really motivated by

cost. Metals like rhodium and platinum

are really expensive, but as the work has


evolved, we realized that there's a lot more to

it than simply pricing. ... There are huge envi-

ronmental concerns, if you think about dig-

ging up platinum out of the ground. Typical-

ly, you have to go about a mile deep and

move 10 tons of earth. That has a massive

carbon dioxide footprint."

Chirik and his research team partnered with

chemists from Merck & Co., Inc., to find more

environmentally friendly ways to create the

materials needed for modern drug chemistry.

The collaboration has been enabled by the

National Science Foundation's Grant Oppor-

tunities for Academic Liaison with Industry

(GOALI) program.

One tricky aspect is that many molecules

have right- and left-handed forms that react

differently, with sometimes dangerous con-

sequences. The Food and Drug Administra-

tion has strict requirements to make sure

medications have only one "hand" at a time,

known as single-enantiomer drugs.

"Chemists are challenged to discover me-

thods to synthesize only one hand of drug

molecules rather than synthesize both and

then separate," said Chirik. "Metal catalysts,

historically based on precious metals like

rhodium, have been tasked with solving this

challenge. Our paper demonstrates that a

more Earth-abundant metal, cobalt, can be

used to synthesize the epilepsy medication

Keppra as just one hand."

Five years ago, researchers in Chirik's lab

demonstrated that cobalt could make single-

enantiomer organic molecules, but only using

relatively simple and not medicinally active

compounds -- and using toxic solvents.

"We were inspired to push our demonstration

of principle into real-world examples and

demonstrate that cobalt could outperform

precious metals and work under more envi-

ronmentally compatible conditions," he said.

They found that their new cobalt-based

technique is faster and more selective than

the patented rhodium approach.

Cobalt could outperform pre-

cious metals and work under

more environmentally compati-

ble conditions

"Our paper demonstrates a rare case where

an Earth-abundant transition metal can sur-

pass the performance of a precious metal in

the synthesis of single-enantiomer drugs," he

said. "What we're starting to transition to is

that the Earth-abundant catalysts not only

replace the precious metal ones, but they of-

fer distinct advantages, whether it's new

chemistry that no one's ever seen before or

it's improved reactivity or reduced environ-

mental footprint."

Not only are base metals cheaper and much

environmentally friendlier than rare metals,

but the new technique operates in methanol,

which is much greener than the chlorinated

solvents that rhodium requires.


"The manufacture of drug molecules, because of their complexity, is one of the most wasteful pro-

cesses in the chemical industry," said Chirik. "The majority of the waste generated is from the solvent

used to conduct the reaction. The patented route to the drug relies on dichloromethane, one of the

least environmentally friendly organic solvents. Our work demonstrates that Earth-abundant catalysts

not only operate in methanol, a green solvent, but also perform optimally in this medium.

"This is a transformative breakthrough for Earth-abundant metal catalysts, as these historically have

not been as robust as precious metals. Our work demonstrates that both the metal and the solvent

medium can be more environmentally compatible."

Methanol is a common solvent for one-handed chemistry using precious metals, but this is the first

time it has been shown to be useful in a cobalt system, noted Max Friedfeld, the first author on the

paper and a former graduate student in Chirik's lab.

Cobalt's affinity for green solvents came as a surprise, said Chirik. "For a decade, catalysts based on

Earth-abundant metals like iron and cobalt required very dry and pure conditions, meaning the cata-

lysts themselves were very fragile. By operating in methanol, not only is the environmental profile of

the reaction improved, but the catalysts are much easier to use and handle. This means that cobalt

should be able to compete or even outperform precious metals in many applications that extend be-

yond hydrogenation."

The collaboration with Merck was key to making these discoveries, noted the researchers.

Chirik said: "This is a great example of an academic-industrial collaboration and highlights how the

very fundamental -- how do electrons flow differently in cobalt versus rhodium? -- can inform the

applied -- how to make an important medicine in a more sustainable way. I think it is safe to say that

we would not have discovered this breakthrough had the two groups at Merck and Princeton acted

on their own."

Chirik's lab focuses on "homogenous catalysis," the term for reactions using materials that have been

dissolved in industrial solvents.

Cobalt should be able to compete or

even outperform precious metals in many

applications that extend beyond

hydrogenation

https://www.rdmag.com/news/2018/06/modern-alchemists-are-making-chemistry-greener


"Homogenous catalysis is usually the realm of these precious metals, the ones at the bottom of the

periodic table," Chirik said. "Because of their position on the periodic table, they tend to go by very

predictable electron changes -- two at a time -- and that's why you can make jewelry out of these

elements, because they don't oxidize, they don't interact with oxygen. So when you go to the Earth-

abundant elements, usually the ones on the first row of the periodic table, the electronic structure --

how the electrons move in the element -- changes, and so you start getting one-electron chemistry,

and that's why you see things like rust for these elements.

Chirik's approach proposes a radical shift for the whole field, said Vy Dong, a chemistry professor at

the University of California-Irvine who was not involved in the research. "Traditional chemistry hap-

pens through what they call two-electron oxidations, and Paul's happens through one-electron oxi-

dation," she said. "That doesn't sound like a big difference, but that's a dramatic difference for a

bottom of the periodic table," Chirik said. "Because of their position on the periodic table, they tend

to go by very predictable electron changes -- two at a time -- and that's why you can make jewelry

out of these elements, because they don't oxidize, they don't interact with oxygen. So when you go

to the Earth-abundant elements, usually the ones on the first row of the periodic table, the electronic

structure -- how the electrons move in the element -- changes, and so you start getting one-

electron chemistry, and that's why you see things like rust for these elements.

Chirik's approach proposes a radical shift for the whole field, said Vy Dong, a chemistry professor at

the University of California-Irvine who was not involved in the research. "Traditional chemistry hap-

pens through what they call two-electron oxidations, and Paul's happens through one-electron oxi-

dation," she said. "That doesn't sound like a big difference, but that's a dramatic difference for a

chemist. That's what we care about -- how things work at the level of electrons and atoms. When

you're talking about a pathway that happens via half of the electrons that you'd normally expect, it's

a big deal. ... That's why this work is really exciting. You can imagine, once we break free from that

mould, you can start to apply it to other things, too."

"We're working in an area of the periodic table where people haven't, for a long time, so there's a

huge wealth of new fundamental chemistry," said Chirik. "By learning how to control this electron

flow, the world is open to us."

(This article was posted on RDMAG on 15 June 2018)

https://www.rdmag.com/news/2018/06/modern-alchemists-are-making-chemistry-greener


COBALT IN ANCIENT

GLASS Cobalt's use in coloring is still a

large market and as our article on

anodizing shows, one which is still

being enhanced by modern elec-

tronic technology. Here, Dr. Clark

examines a somewhat older, but

none the less original, cobalt tech-

nology

The identity of the first glass makers is lost in

the mists of time. It may have been the an-

cient Sumerians, or the prehistoric Egyptians

who cast the first glass beads, but the art of

glass making soon spread throughout the

world of the ancient Near East.

Although they learned the art of making true

glass relativity late, once they were thor-

oughly familiar with the techniques, the

Egyptians' unrivalled natural resources


COBALT INSTITUTE HISTORICAL SERIES

Dr. S.J. Clark, City University, Northampton Square, London

(unlimited sand, plentiful alkali and access to

wide range of coloring minerals) made them

the world's preeminent glassworkers until the

Moslem conquest enabled that mantle to be

passed on to the Venetians.

Until Greek times, most glass was opaque

rather than transparent or even translucent.

Indeed, most of the glass produced in the

ancient Near East was not true glass but ra-

ther the material archaeologists call faience,

i.e. a partly vitreous core of granular silica

which is fused with alkali and coated with al-

kali glaze. Once the basic skills of glassmak-

ing was mastered, the ancient craftsmen

searched for the ways to produce new col-

ours and it was soon discovered that some of

the most intense materials for colouring

glass contain the element known as cobalt.


The colour of a glass or glaze depends on

the relative populations of the two coordi-

nation spheres and of the possible oxida-

tion states. While under suitable condi-

tions colours as diverse as pink, purple,

green and blue may be obtained with co-

balt, the Egyptians and other peoples of

antiquity used it almost exclusively for the

production of shades of blue, violet and

indigo, and occasionally, black. Such in-

tense blue colouration is produced by

003+ in a tetrahedral environment. The

final shade is modified by the other ele-

ments almost always present in the glass:

copper is almost always found in blue

glasses and manganese is frequently pre-

sent, especially in purple glass. Even so,

cobalt is such an intense chromophore

that a cobalt concentration of 0.05% is suf-

ficient to define a glass as a cobalt glass. In

concentrations greater than 0.2%, COO

tends to give indigo or violet glazes rather

than blue.

Very often, it was these darker shades

which were obtained with cobalt, since the

lighter shades such as turquoise could be

made from the more readily obtainable

copper ores. In general, indigo differs from

blue by the higher concentration of co-

balt, just as purple differs from violet by

the degree of redness. Indigo-violet cobalt

glazes reddened with manganese and

nickel, were very popular during the Am-

arna and Ramesside periods in Egypt

(1380-1280 BC).


Much later, in Ptolemaic times, there is evi-

dence of the intentional use of cobalt to

darken the greyish-black colour of reduced

iron to give black glazes.

The earliest deliberate use of COO in an-

cient Egypt occurred during the reign of

Thuthmosis Ill (ca. 1450 BC), but cobalt re-

mained rare for many years. Its use was

greatest in the late 18th Dynasty and con-

tinued for some 200 years before falling in-

to disuse after the collapse of the Egyptian

empire during the 20th Dynasty. Cobalt

pigments were rarely used again until Ptol-

emaic times (4th century BC).

At about the same time as the cobalt col-

ours were introduced, the Egyptians devel-

oped true poly. chrome faience and could

produce examples containing up to six in-

terlocking colours. Because cobalt shows

little tendency to migrate, designs in indigo

or violet on green or pale blue, or in green

on cobalt blue remain sharp after firing.

Tubes and dishes with green or turquoise

inscriptions set in cobalt-coloured indigo or

violet blue grounds, date from the late 18th

Dynasty, together with examples with the

inverse colouring. A fluted indigo-blue ves-

sel found in Amarna has an inner surface

decorated in a four colour mosaic separated

by a dotted blue ground.

COBALT SOURCES

Even at the height of its use, in the late 18th

Dynasty, cobalt was only used in about half

the blue (as opposed to indigo or violet)

glazes. In addition, whether in faience, true

glass, and/or painted on pottery, it is almost

unknown outside the royal residences of

Thebes and Tell el Amarna. This localised

distribution of finds shows that cobalt must

have been quite a rare commodity which

was only available to those with access to

the royal workshops or the largest temples.

The source of this Egyptian cobalt was a

mystery until comparatively recently when

systematic X-ray fluorescence analysis of a

large number of samples showed clear cor-

relations between the concentrations of

certain elements (zinc, magnesium and alu-

minium) in glazes and their cobalt content.

The presence of these elements shows that

the Egyptian cobalt could not have come

from the ores of the Caucasus and Iran but

from the alum deposits of the Great West-

ern Oases.

A simple process in which the alum is dis-

solved in water and an alkali (such as na-

tron) used to precipitate out the metals,

yields a solid which could be dried and used

as a pigment. This cobalt


Embedded in the

alums of the Dakhla

and Kharga oases,

are pink and laven-

der veins containing

up to 3.5% cobalt,

which contained the

mineral known to

the Ancient Egyp-

tians as weshebet

Embedded in the alums of the Dakhla and Khar-

ga oases, are pink and lavender veins containing

up to 3.5% cobalt, which contained the mineral

known to the Ancient Egyptians as weshebet.

pigment was not only used in Egypt but was

certainly exported to Mycenae Greece. It was

also probably used in Crete, although no cobalt

has yet been found in any Minoan glasses.

After the loss of the Egyptian Empire, cobalt

rapidly felt into disuse and is virtually unknown

for some 500 years.

When cobalt was again used (after the 7th cen-

tury BC), it was much purer than before and

must have been imported. Under the Ptolemies,

cobalt was frequently used lavishly (often at lev-

els over 1 % CoO) ,and an indigo-violet paste

with a very high cobalt concentration was intro-

duced to fill incised designs on dark blue

grounds, and cobalt-containing iron glazes were

often used to provided black. Unlike the earlier

period, cobalt glazes were produced along the

whole length of Egypt, and was obviously much

cheaper. The high purity and the presence of

traces of arsenic identify the new sources of co-

balt as the mines of Iran.

True glass vessels were very rare in ancient

Egypt until the reign of Amenophis Il, son of

Thuthmosis Ill, when the first major workshops

were set up. Within a short time the Egyptians

far surpassed the work of their Asiatic neigh-

bours. No less than four glassworks, the oldest


known, have been excavated at el Amarna,

where glass making reached heights unsur-

passed until the invention of glass blowing.

Over half the blue glass objects found in Egypt

from this time were coloured by cobalt rather

than copper. After the collapse of the New

Kingdom, glassmaking was at a low ebb until

the 4th century BC when Greek techniques were

introduced. Alexandria became one the great

glass manufacturing centres of Roman times,

producing some of the finest examples of

opaque cobalt glass ever made, the Portland

Vase being the best known example..

THE OLDEST COBALT

The oldest known example of true cobalt glass

is cullet found beneath a pavement at ancient

Eridu (in Iraq) and is dated to the 21st century

BC. This piece, and all the cobalt glasses and

faience manufactured in ancient Mesopotamia

and Syria, used Iranian cobalt. This Iranian co-

balt, the manganese-free cobaltite, was later

exported even as far as China where it was used

in the production of the "Mohammedan blue"

porcelain pigment. Soon after 1400 A.D., how-

ever, this ore was replaced by native Chinese

ore of the absolan type. Manganese-free Irani-

an cobalt continued to be used for native Per-

sian blue-and-white ceramics even into the

20th century.

The oldest known

example of true

cobalt glass is cullet

found beneath a

pavement at ancient

Eridu (in Iraq) and is

dated to the 21st

century BC


COBALT INSTITUTE

www.cobaltinstitute.org

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GU1 4AP Guildford

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For further information:

[email protected]

COBALT INSTITUTE

CHAIRMAN

G. Ethier (Umicore)

VICE CHAIR

T. Litzinger (New Providence Metals)

DIRECTORS

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D. Elliott (CMOC International)

G. Jones (ICoNiChem)

J. Lowe (Dynatec)

A. McCarthy (Albemarle)

V. Mittenzwei (Kennametal, Inc.)

M. Oehlers (Shu Powders)

M. Ohyama (Sumitomo MM)

H. Pihlaja (Freeport Cobalt)

M. Shumba (Borchers Americas )

P. Ringeisen (Sandvik)

F. Schulders (Glencore International)

M. Shepherd (Vale)

E. Taarland (Chambishi Metals)

THE COBALT INSTITUTE

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