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    INSPIRATION AND CHAT

MOLYBDENUM

Posted November 24th 2015

Discovered in 1778 by Carl Wilhelm Scheele, Molybdenum is a chemical element with symbol Mo and atomic number 42. Its name is derived from the Neo-Latin molybdaenum, and Ancient Greek molybdos, both meaning lead, as the element was originally found in a mineral known as molybdenite which had been confused for a lead compound. It is not a naturally occurring free metal, but rather materialises in various oxidation states in minerals. It is the 42nd most abundant element in the Universe and the 54th most abundant element in the Earth’s crust.

For about a century after its isolation, Molybdenum had no industrial use owing to the difficulty of extracting it. It was not until 1913 that Frank E. Elmore developed a froth flotation process to recover molybdenite from ores, which is still the primary isolation process today.

Molybdenum has the sixth highest melting point of any element and is used to make the electrodes for electrically heated glass furnaces, as well as some electrical filaments. This property makes it incredibly versatile. Its ability to withstand temperatures without significantly expanding makes it useful in the manufacture of armour, aircraft parts and industrial motors too. Some steels which have additions of molybdenum can withstand pressures of up to 300,000 pounds per square inch.

The primary metallurgical use of Molybdenum is as an alloying agent in steel. It has many properties and is used to make steels for a wide range of applications for example construction, earth moving, automotive and marine. The HSLA.grades have perhaps the lowest levels of molybdenum often less than 1% however additions of up to 9% are found in the “M” series range of high speed steels. It is often alloyed with Nickel and chromium to form heat and corrosion resistant materials used in the chemical industry. Molybdenum is also present in cutlery grades like 440C and in tool steels where it helps improve wear resistance and hardness.

In addition to its commercial uses, Molybdenum is also an essential trace element and crucial to the survival of lifeforms. It functions as a cofactor for a number of enzymes that catalyse important chemical transformations in the global carbon, nitrogen and sulphur cycles. The human body contains 0.07 mg of Molybdenum per kilogram of weight and it is also present in tooth enamel, helping to prevent decay.

William Rowland is the UK appointed sales agent and distributor for the Kennecott Molybdenum Company.

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CHROMIUM

Posted November 20th 2015

Derived from the Greek word for colour, Chroma, Chromium is a chemical element with the symbol Cr and atomic number 24. It is the first of the elements in Group 6 of the Periodic Table, which contains transition metals. Chromium has a long history and was used by the Chinese in the Qin Dynasty over 2000 years ago to coat the weapons that can be found with the Terracotta Army.

Chromium is a steely-grey, hard and brittle metal. It can be polished to a high standard and resists tarnishing so it is often plated to other metals to form a protective and aesthetically pleasing covering. It also has an extremely high melting point at 1860°C and is often added to steel to harden it and form stainless steel – an alloy containing at least 10% chromium. Other chromium-steel alloys can be used to make armour plate, safes, ball bearings and cutting tools.

Perhaps it is not a surprise given the origins of its name, but Chromium can also be used to form several colourful compounds with industrial uses. Lead chromate can be used as a yellow pigment in paints whilst chromic oxide is used as a green pigment. Chromium compounds are also responsible for the colour in rubies and emeralds. Chromium salts, in particular chrome alum and chromium (III) sulfate, are used in the tanning of leather and chromium tanned leather can contain between 4-5% chromium.

Approximately 28.8 million metric tons of marketable chromium ore were produced in 2013. The largest producers have been South Africa, Kazakhstan, Turkey and India, although other countries are also involved in the production of chromium ore.

William Rowland is the UK distributor for DCX Chrome (formerly Delachaux), who produce aluminothermic grades 99.4% min for air melting and 99.6% Cr min. for vacuum melt applications. DCX Chrome also produces a unique double degassed briquette (DDB) 99.8% Cr min. which is equivalent to the highest quality electrolytic grades.

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THE PERIODIC TABLE

Posted November 10th 2015

The periodic table organises the chemical elements by their atomic number (number of protons in the nucleus), electron configurations and recurring chemical properties, in rows and columns. The rows are called periods and the columns groups, and generally within a period, the left side shows metals whilst the right shows non-metals. But how did we end up with the modern periodic table?

The earliest attempt to classify the elements was made by Antoine Lavoisier when he grouped the elements into gases, non-metals, metals and earths, based on their different properties. Whilst several other attempts were made to classify the elemts it was not until the 1860s that real progress began to be made as more accurate lists of atomic mass became available.

In 1869 a Russian chemist named Dmitri Mendeleev published what he called the Periodic System, the precursor to what we know as the Periodic Table. Although previous attempts had been made to categorise the elements, Mendeleev was the first to successfully find order and create the basis of the modern Periodic Table still in use today. Mendeleev’s approach was to write the properties of the elements on pieces of card and arrange them into different orders. By doing this he realised that if he put them in order of increasing atomic weight, certain types of elements regularly occurred.

When Mendeleev arranged the table, it also enabled him to predict the discovery of new elements, for which he left blank spaces. For instance, Gallium, was not discovered until after Mendeleev published the table but he had already predicted its properties and left a space for what he called ‘eka-aluminium’ – the element following aluminium in the table. The further discoveries of Scandium and Germanium helped cement the reputation of Mendeleev’s periodic table as everyone agreed that he had found a working system.

Scientists use the periodic table to understand why elements react in the way they do. They are able to form understandings and even discover new elements. Today we are still adding elements to the table, with the most recent addition being 117 in 2014, named Ununseptium. Our understanding is constantly evolving and developing, but the periodic table that Mendeleev posited in 1869 forms the basis of our understanding today.

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