Melting pot furnace

Fig. 3.20. Large metal melting pot furnace. With large containers, tangential heating minimizes nonunitbrmity around the periphery. More small type E or type H burners usually help. (See also fig. 1.15.)...

An aluminum scrap fire developed near a melting furnace. Fire departments responded and sprayed water on the flames. Suddenly the pot furnace exploded. It is presumed that water from the fire hoses entered the furnace which contained about 900 kg of molten aluminum... 

Indirect-Fired Equipment (Fired Heaters) Indirect-fired combustion equipment (fired heaters) transfers heat across either a metallic or refractory wall separating the flame and products of combustion from the process stream. Examples are heat exchangers (discussed in Sec. 11), steam boilers, fired heaters, muffle furnaces, and melting pots. Steam boilers have been treated earlier in this section, and a subsequent subsection on industrial furnaces will include muffle furnaces. 

The melt used in this work was prepared from the residue of hydrogen-donor extraction of Colstrip coal with tetralin solvent in such a way as to simulate the composition of an actual spent melt. The extraction was conducted in the continuous bench-scale unit previously described (17) at 412°C and 50 min residence time. The residue used was the solvent-free underflow from continuous settling (17) of the extractor effluent. The residue was then precarbonized to 675°C in a muffle furnace. The melts were blended to simulate the composition of a spent melt from the direct hydrocracking of the Colstrip coal by blending together in a melt pot zinc chloride, zinc sulfide, and ammonium chloride, ammonia, and the carbonized residue in appropriate proportions. Analysis of the feed melt used in this work is given in Table I. 

The thermal efficiency of glass melting furnaces is relatively low, in particular that of pot furnaces. Values of 20—35% are reported for tank furnaces with classical heating (see below). Efforts to raise thermal efficiency led to experiments with shaft and rotary furnaces, with fluidized bed melting furnaces, etc. Only electric boosting and all electric glass furnaces have so far found wider practical application. 

Crystal glasses were traditionally melted in pot furnaces, but nowadays small continuous tank furnaces are used. Lead glasses are conveniently melted in Unit-Melter furnaces, lead-free glasses in all-electric furnaces with a daily output of several tons (cf. Fig. 102). Machine forming is being gradually introduced even for these types of glass. 

The reaction is carried out in pot furnaces (low brick-lined hearths with lids), continuous furnaces or rotary plate furnaces. The melt produced in the furnace is mashed with water, the undissolved material removed and the solution concentrated to 60 to 62% sodium sulfide by evaporation in cast iron vessels. This concentrated solution solidifies at ca. 90°C. 

Qouros was a god of Thera, today s Island of Santorini. " After the eruption of the volcano, the island was renamed Qera after this god. Qouros and Qera have the same meaning of cauldron, melting pot or furnace as the Canaanite kur. 

Boetius Furnace. A semi-direct coal-fired pot furnace for melting glass this was the first pot-fumace to use secondary air to increase the thermal efficiency. 

Hermansen Furnace. A recuperative pot-furnace for melting glass the first furnace of this type was built in Sweden in 1907 and was soon afterwards introduced into England and elsewhere. 

Pot Furnace. A furnace in which glass is melted and refined in pots (q.v.), or in which a frit is melted for use in a glaze or in a vitreous enamel. 

The five stages of the melting process as described in Sects. 3.1 and 3.2 occur in the melting equipment. These processes occur in chronological order in a discontinuously working pot furnace (Fig. 3.5), or parallel in different places in the continuous tank furnaces. Many types of melting furnaces are used. A specific example of a continuously working furnace is shown in Fig. 3.11. 

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