Metallurgical Processes

The substances that are capable of withstanding very high temperatures without melting or becoming soft are called refractory materials like- SiC (carborundum), Al₂O₃, SiO_2, etc. Blast furnace is used for the smelting of iron, copper and lead ores. Calamine (ZnCO₃) is the ore of zinc while casseterite (SnO₂) is the ore of Sn.

A. Mild steel contains 0.15% to 0.30% of carbon. Medium steel has 0.30% to 0.60% of carbon. B. Promoted iron is used as the catalyst in the Haber-Bosch process for the making of NH₃. C. Mild steel is malleable and can be bent or machined. This is hardened (tempered) by heating to red heat and quenched by plunging into water or oil.

P. The Parkes process, patented in 1850, uses zinc to form a material which the silver enters. This floats on the lead and can be skimmed off.
Q. The Pattison process was patented by its inventor, Hugh Lee Pattinson, in 1833. It depended on well-known material properties; essentially that lead and silver melt at different temperatures. The equipment consisted of a row of about 8-9 iron pots, which could be heated from below. Argentiferous lead was charged to the central pot and melted. This was then allowed to cool, as the lead solidified, it was skimmed off and moved to the next pot in one direction, and the remaining metal was then transferred to the next pot in the opposite direction. The process was repeated in the pots successively, and resulted in lead accumulating in the pot at one end and silver in that at the other. R. Fire process - The initial product of copper smelting was impure black copper, which was then repeatedly melted to purify it, alternately oxidizing and reducing it. In one of the melting stages, lead was added. Gold and silver preferentially dissolved in this, thereby providing a means of recovering these precious metals. To produce purer copper suitable for making copper plates or hollow-ware, further melting processes were undertaken, using charcoal as fuel. The repeated application of such fire-refining processes was capable of producing copper that was 99.25% pure.

In case of extraction of iron, in roasting step all taken pure haematite converted to FeO that combines with oxygen and form Fe₂O₃. So, the final product of the roasting step is FeO₃ in the extraction of iron and thus there is no need of roasting.

Stainless steel is an alloy (mixture) primarily composed of iron, carbon, and chromium (minimum 10.5%). The chromium forms a protective oxide layer that prevents rust and corrosion. It is not a pure element, nor a compound, nor a mixture of only non-metals.

Sodium is obtained by electrolysis of the mixture of sodium chloride and calcium chloride.This method is known as Down's process.

Copper turns green because of a process known as oxidation, which is the removal of electrons from the substance.

Cast iron is produced in a blast furnace and contains the highest percentage of carbon among common iron forms, typically ranging from 2 percent to 4 percent. Wrought iron has the lowest carbon content, while mild and stainless steels fall in between.

Galvanization is the process of applying a protective zinc coating to iron or steel to prevent rusting. Zinc acts as a sacrificial anode, corroding preferentially to protect the underlying metal even if the coating is scratched. Tin and aluminium provide barrier protection only, while gallium is not used for galvanization.

this option is correct because Ma comes higher than Boron and silicon in the electrochemical series hence can be used as a reducing agent in the metallurgy of boron and silicon.

This option is correct because silver obtained from argintiferous lead still contains lead impurities. Thus, the lead is removed by silver.

Electroplating is the process of using an electric current to deposit a thin layer of metal onto the surface of another object. This is commonly done to improve corrosion resistance, enhance appearance, or increase surface hardness.

Laterite soil is formed through the process of intense leaching, where heavy rainfall washes away silica and lime, leaving behind iron and aluminum oxides. This process occurs in tropical climates with alternating wet and dry seasons.

Due to very high melting point of tungsten it can withstand very high temperature inside the bulb without burning. So filament of the bulb is made of tungsten.