Reverberatory hearth

The earliest reverberatory hearths were introduced around 1720 in Silesia and England. Early types were the Corinthian furnace, the English or Hintshire furnace and the Silesian fiunace. Silesian furnaces used in Germany were up to 25 foot (7600 mm) long by 8 foot (2400 mm) wide, with five working doors in each side. Labour requirements were 15 to 20 man hours per tonne of lead produced, with coal consumption close to 0.8 tonnes per tonne of lead produced. 

At the Pontgibaud smelter in France, a reverberatory hearth was used for batch calcining, followed by elevation in furnace temperature to cause surface melting and sintering of the calcine into an agglomerated mass, rather than complete melting of the charge. This was withdrawn from the furnace, cooled and broken into lump for blast furnace feed. 

Use of coke for iron smelting 1720 Reverberatory hearth smelter for lead... 

Flash smelting is efficient because the fuel value of the sulfur and iron in the charge is fully used, and the productivity (8—12 t/d of charge processed per square meter of hearth) is higher than that of the reverberatory or electric furnace. 

In hquidation, tin is heated on the sloping hearth of a small reverberatory furnace to just above its melting point. The tin mns into a so-called poling ketde, and metals that melt sufficiently higher than tin remain in the dross. Most of the iron is removed in this manner. Lead and bismuth remain, but arsenic, antimony, and copper are partly removed as dross. 

Furnace types include cupolas, electric arc, induction, hearth or reverberatory, and crucible. Because of the different characteristics of metals, different inputs are required and different pollution is released from each type. Table 4.1 summarizes the types of furnaces depending on the type of metal being used. 

Smelting in Blast Furnaces.—The use of the blast furnace involves the necessity of a somewhat different treatment. The Scotch furnace or ore-hearth, described at page 465, may be taken as the type of this kind of furnace when adapted to the smelting of lead ores. Generally very rich ores are operated upon where the Scotch furnace is employed end these are subjected before smelting to a preliminary roasting in a furnace of the reverberatory class,... 

Reverberatory furnaces3 are particularly suitable for fines and flue-dust from the blast-furnaces. Their walls and roof are lined with silica bricks, and the hearth with silica sand. A typical charge consists of2 ... 

The hearth type furnace is also known as a reverberatory or bale-out furnace. It is a static furnace with direct heating. Hot air and combustion gases from oil or gas burners are blown over the metal (melt) and exhausted out of the furnace. The hearth t5q)e furnace finds its main application in non-ferrous metal melting. A typical furnace design is given in Figure 2.18. 

Hearth type (or reverberatory) furnaces exist in various sizes and shapes. Large hearth type furnaces allow rapid melting and can handle bulky charge material, but the direct contact between the flame and charge material may lead to high metal losses, gas pick-up and to considerable oxide contamination. Temperature control can also be difficult. This type of furnace is used less because of its relatively low thermal efficiency (around 1100 kWh/tonne). The hearth type furnace is also used for copper alloy melting (see Section 3.5.1). [175, Brown, 1999]... 

Hearth type furnace static furnace with direct heating, also called reverberatory furnace and bale-out furnace... 

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