Reverberatory Furnace: Working, Applications, Construction, Sample Questions

A Reverberatory Furnace is a furnace that isolates the material being treated, from contact with the fuel but not with combustion gases. A reverberatory furnace is primarily used in the extraction of metals such as copper, tin, nickel and aluminium, as well as to manufacture certain types of cement and concrete. The processes of refining and smelting are carried out in a reverberatory furnace only. 

Keyterms: Reverberatory Furnace, Copper, Tin, Nickel, Aluminium, Gas, Fuel, Metal, Charcoal, Coal, Wood, Mineral coal

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History

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The first reverberatory furnaces were probably used to melt bronze for casting bells during the medieval period. In the late 17th century, they were initially used to smelt metals. Such furnaces were then commonly used to smelt metals, as well as tin, in the decades that followed. They had an advantage over prior systems since they used mineral coal rather than charcoal or 'white coal' (chopped dried wood). Henry Cort then invented the puddling furnace in the 1780s to replace the earlier finery process. It was a type of reverberatory furnace.

Reverberatory Furnaces

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Construction

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The reverberatory furnace is made up of two single-chimney dome-shaped furnaces with fire and heat generated by charcoal reverberating against the furnace walls and ceilings, melting the iron within. Today's reverberatory furnaces are generally made out of a rectangular steel box lined with castables or refractory bricks with non-wetting qualities. At one end, there is a vertically rising door, and the burners are normally on the opposite side of the furnace. A pouring spout and the exhaust gas duct are located opposite the burners. Roofs are also formed of refractory bricks, which are robust and aid in the generation of higher temperatures.

Construction

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Working

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In terms of functioning, heat is generally transferred across the hearth which contains the ore combination in a reverberatory furnace. Radiation from the refractory bricks used in the walls and roof is the primary method of heat transfer. The ore receives additional heating from the burner. The furnace's ceiling is also slightly arched and sloped toward the flue bridge, which deflects the flame for reverberation. The mixture is continuously heated until it melts.

Meanwhile, the molten impure metal is gathered in the thick hearth, which is built of a robust substance that can withstand slag disintegration. In the furnace, this procedure is continued until the ore concentrate is drained at regular intervals. After that, the substance is transferred to a converter for further processing.

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Advantages and Disadvantages

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The advantages of reverberatory furnace are:

1. The reverberatory furnace has a high volume processing rate.
2. It has low operating and maintenance costs.

The disadvantages of reverberatory furnace are:

1. The reverberatory furnace has the high metal oxidation rates
2. It has low efficiency.
3. It has large floor space requirements.

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Difference between Blast Furnace and Reverberatory Furnace

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Blast Furnace:

• To make iron from iron ore, a blast furnace is commonly used. This is a vertical shaft furnace that is loaded with coke, iron ore, and limestone, and a powerful ‘blast' of air is pumped at the bottom to burn the coke and produce carbon monoxide, which combines with the iron ore to remove oxygen, releasing the molten iron metal. 
• The limestone creates a slag with a lower melting point, which cleans the iron by eliminating impurities. The iron is then taken to the next step, which is often oxygen blowing, which burns out much of the carbon and other impurities to produce steel, which is essentially simply iron with a small amount of carbon and traces of other elements that increase its performance.

Blast Furnace

Reverberatory Furnace:

• A reverberatory furnace is essentially a flat open hearth with a firebrick roof atop it. It's an older sort of furnace that's primarily used for copper extraction.
• Copper oxide concentrate is mixed with coke and silica sand (to make slag) and placed on the furnace's floor or hearth, where it is melted by a tremendous flame.
• The radiant heat is reflected from the roof (thus the furnace's name) to heat the ore combination, and the carbon removes the oxygen from the copper, generating carbon monoxide and carbon dioxide and thus releasing the copper metal, which is periodically tapped from the furnace.

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Things to Remember

• A metallurgical or process furnace that isolates the material being treated from contact with the fuel but not with combustion gases is known as a reverberatory furnace.
• The first reverberatory furnaces were probably used to melt bronze for casting bells during the mediaeval period.
• Sir Clement Clerke and his son Talbot built cupolas or reverberatory furnaces around 1678.
• The reverberatory furnace is made up of two single-chimney dome-shaped furnaces, with fire and heat generated by charcoal reverberating against the furnace walls and ceilings, melting the iron within.

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