Wallid Guergour | Information on materials, zinc.
The third most important metal (after iron and copper), zinc is a shiny blue-grey metal that is brittle at room temperature. This metal is often chosen for its resistance to atmospheric corrosion and is therefore used mainly for galvanisation and as an additive in bronzes and brasses. With the industrialisation of the modern world, the consumption of zinc has increased (transport, infrastructure, building, industrial equipment), partly because of its chemical properties. Zinc is also used in health, as this trace element plays an indispensable role in growth, immune response and neurological functions.
The family of zinc alloys includes a plethora of compounds, zinc is commonly combined with copper (brass), aluminium (zicral), magnesium (zamak), copper and nickel (virenium) and even cadmium and titanium. The mechanical properties are modified by the chemical composition, but also by the thermo-mechanical treatments undergone (annealing, structural hardening, etc.). Thus, some alloys are designed for die-casting others are used in goldsmithing, or used for certain brazes, or for roofing and gutters. The most common process for casting zinc alloy parts is still die-casting.
In recent decades, as with copper and gold, the industrialisation of the modern world has greatly increased zinc consumption. Of the total zinc consumed in the world today, approximately 30% of production comes from recycling and 70% from mining. The zinc mining industry is relatively fragmented, with Asia becoming the main producer after the American continent, while activity in France has been halted.
Zinc ores are essentially sulphide ores (blende and würtzite) of varying degrees of complexity depending on their mineral associations, with some deposits of oxidised ores (zincite, hydrozincite and smithsonite). Today, the main processing method for zinc concentrates is sulphuric acid hydrometallurgy. First, the zinc ores are roasted to oxidise the zinc sulphides. This roasting, using the fluidised bed technique, results in the formation of sulphur dioxide, which is used for the production of sulphur or sulphuric acid.Here is an article about tungsten
In the field of anti-corrosion, particularly in the automotive sector, new coatings have been developed using zinc-based co-deposits that are comparable or even more effective than pure zinc coatings. These alloyed systems, mainly zinc-nickel, zinc-nickel-iron and zinc-cobalt, also allow the creation of finishes for specific purposes.
In terms of recycling, on average 45% of zinc-containing waste is recycled. Some products such as zinc sheet roofing have a rate of over 90%. Conversely, the rate is zero for zinc in pharmaceutical products.