Reverberatory Furnace

A reverberatory furnace is a metallurgical or process furnace that separates the material to be processed by contact with the fuel , but not by contact with the combustion gases . The term reverberation is used here in the general sense of rebounding or reflection , and not in the acoustic sense of resonance .

Reverberatory Furnace


Chemistry determines the optimal relationship between fuel and material, among other variables. Reverberatory furnaces can be contrasted with a blast furnace, on the one hand, in which fuel and material are mixed in the same chamber, and, on the other hand, with a crucible , muffling or retort furnace , in which the subject matter is separated. Fuel and all products of combustion including gases and fly ash. However, there are many furnace designs, and the metallurgy terminology is not very consistently defined, so it is difficult to explicitly refute other ideas.

Application and comparison with blast furnace

Applications of these equipment fall into two general categories, metallurgical melting furnaces, and low temperature processing furnaces commonly used for metal ores and other minerals.

A reverberatory furnace is at a disadvantage in terms of efficiency compared to a blast furnace due to the spatial separation of the burning fuel and subject material, and it can effectively utilize both the reflected radiant heat and the direct contact with the exhaust gases. is required for ( convection ) to maximize heat transfer . Historically these furnaces have used solid fuels, and bituminous coal has proven to be the best option. Brightly visible flames (due to a substantial volatile component) of anthracite coal or charcoal Gives more radiant heat transfer than Contact with the products of combustion, which may add undesirable ingredients to the subject material, is used to advantage in some processes. Control of the fuel/air balance can shift the exhaust gas chemistry towards an oxidizing or reducing mixture, and thus the chemistry of the material to be processed. For example, cast iron can be puddled in an oxidizing environment to convert it’s low carbon to mild steel or bar iron . There is also a reverberatory furnace in Siemens-Martin oven open heart steelmaking .

Reverberatory furnaces (in this context, commonly called air furnaces ) were also formerly used to melt brass, bronze and pig iron for foundry work. They were also the major smelting furnaces used in the production of copper, for the first 75 years of the 20th century, using either roasted calcined or crude copper sulfide concentrate. [1] While they have been replaced in this role earlier by flash furnaces and more recently by Osmelt [1] and ISASMELT furnaces, [2] as they are very effective in producing slag with low copper losses.


The first resonance furnaces were probably in medieval times, and were used to smelt bronze for the casting of bells . They were first applied to smelting metals in the late 17th century. Sir Clement Clerk and his son Talbot built the cupola or reverberatory furnace in the Avon Gorge below Bristol in about 1678 . In 1687, while the smelting of lead was hindered (by litigation), they switched to copper. In subsequent decades, reflective furnaces were widely adopted for smelting these metals and tin. They had the advantage over the older methods in that the fuel was mineral coal, not charcoal or ‘white coal’ (shredded dry wood).

In the 1690s, he (or associates) implemented a reverberatory furnace (known in this case as an air furnace) to melt pig iron for foundry purposes. It was used at Coalbrookdale and several other places, but became obsolete in the late 18th century with the introduction of the foundry cupola, a type of small blast furnace, and a significantly different species from the reverberatory furnace. The puddling furnace, introduced by Henri Cort in 1780 to replace the old decoration process, was also a variety of reverberatory furnace.

Aluminum melting

Today, reverberatory furnaces are widely used by die-casting industries to melt secondary aluminum scrap for end use. citation needed ]

The simplest reverberatory furnace is nothing more than a steel box lined with alumina refractory brick with a flue at one end and a vertical lifting door at the other. Conventional oil or gas burners are usually placed on either side of the furnace to heat the brick and the final bath of molten metal is poured into the casting machine to form the ingots.