Zinc is a metal element with the symbol Zn and an atomic number of 30. It has a melting point of 419.8 °C and a boiling point of 907 °C. This metal is usually white or gray, which becomes dark due to the humidity of the air and when it burns, it produces a light green or blue flame. This element is insoluble in water but easily reacts with non-oxidizing acids.
This metal is offered in various commercial forms such as ingot, sheet, wire, rod, and balls. After iron, aluminum, and copper, zinc is the most widely used metal in the world and it has many industrial and biological usages. Between 100 °C and 150 °C, this metal is soft and malleable and can be hammered into thin sheets without breaking.
This feature has made zinc one of the most used metals in various fields such as:
– Galvanizing process, preventing steel and iron from rusting
– The automotive and shipbuilding industry
– The military industry
– The production of kitchen utensils
– Producing environmentally friendly batteries
– Food and pharmaceutical industry
– Agricultural industry, for making fertilizers
And much more…
You may also like to know that:
– over 12 million tons of zinc is produced yearly around the world
– about 75% of zinc consumed in the world is extracted and produced from mines and the remaining 25% is obtained from recycled zinc
– more than 60% of the zinc consumed per year is used in the process of electroplating and galvanizing
– this metal comprises an estimated 0.004% of the Earth’s crust
– this element is found everywhere in our daily life: in every cell of the human body, in the earth, in the food we eat, and in products we use (sunblock, automobiles, cosmetics, airplanes, appliances, surgical tools, zinc lozenges)
The Making of Zinc Ingot
Mining
It all starts with traces of zinc which can be found just about everywhere in the earth’s crust.
The zinc concentrate is gathered from mines and shipped to the factory.
From there, train loads that contain zinc concentrate are transported to the sites to undergo a four-stage process of roasting, leaching and purification, electrolysis, and casting.
Roasting
Zinc concentrate is fed into a roaster. This is the first step in the production process.
In the roaster, raw zinc materials are burned with air and are calcined. Calcined zinc looks like sand and has a temperature of 950 degrees Celsius.
The roasting process is fully automated and constantly monitored and controlled by operators from a control room.
Leaching and Purification
This step is pure chemistry. The produced calcine is dissolved in sulfuric acid during a process called leaching.
To produce a very pure zinc sulfate solution, a wide range of other metals are separated during this step such as lead, gold, silver, copper, cadmium, and cobalt. The zinc sulfate solution enters the next stage; Electrolysis.
Electrolysis
In the electrolysis department, the zinc contained in the solution is deposited onto aluminum cathodes in a process called “electrowinning”. This happens by passing an electric current through cathodes and anodes.
The cathodes are removed from the cells and the zinc sheets are stripped from the cathodes and sent to casting. In casting, cathode zinc is melted in furnaces and the molten zinc is made into blocks and ingots.
The electrolysis stage is a fascinating process that takes a little longer than 22 hours. With using large amounts of electricity, pure zinc is deposited on aluminum plates. These plates are lifted out of the cells and some machines strip off the zinc and the empty plates are returned to the cells where the process starts all over again.
Melting and casting
As the fourth and last step, zinc is re-melted and cast in various shapes and sizes.
Besides that, specific alloys are cast by adding a variety of alloying materials.
Finished zinc has many uses: construction, transport, industrial machinery, communications, electronics, consumer products,… and much more.
The main use of zinc around the world is in protecting steel from corrosion. Adding a thin layer of this metal is one of the most environmentally friendly ways to stretch the lifetime of a steel product by approximately 12 times.
