Heat induration

Typical in (iron) ore industry any agglomeration method involving growth agglomeration with subsequent heat induration. 

Figure 351. Diagrams representing the three most common heat induration methods and schematic representations of complete pelletizing plants using the particular induration method.(a) Shaft furnace, (b) straight grate, (c) Grate-Kiln. (Courtesy of Boliden Allis, Milwaukee, Wis., USA.)...

Stage 1 Pressure sore is generally reversible, is limited to the epidermis, and resembles an abrasion. It is best described as an irregularly shaped area of soft-tissue swelling with induration and heat... 

The material shows clearly the difference of optical transparency of irradiated zones. It seems that the effect is limited to the range of the a-particles, which would tend to prove that the radioactivity is unable by itself to induce the entire induration of the asphalt. This does not exclude the effect of the released heat. 

Figure 4.1 Basic diagram of the quartz flow reactor (1 heating up zone 2 reaction zone and 3 induration zone).

Pelletizing (cf. tumbling agglomeration ) Green balls or pellets of ore or minerals are hardened by heat treatment with attendant loss of moisture and volatile matter. Pellet induration, pellet firing Travelling grate, rotary kiln, vertical shaft furnace... 

Solid bridges 1. Sintering, heat hardening 1. Induration of iron ore 31... 

Sunstone A stone composed of indurated naptha or bitumen, indurated by a terrene heat. It is a species of Gagates. 

LITHANTHRAX, PIT COAL, STONE COAL — A species of Gagates, and nothing but Bitumen indurated and excocted by heat under the surface of the earth. There are two species of this Coal, one of which is light and of little density, while the other is heavy. It is said that the former will sometimes float upon the surface of water, and it is referred to by Theophrastus as an earthy or stony pit coal. The second species was known to the Greeks, but it is not mentioned by Pliny, and was in all probability unknown to him. It seems to have been described by Theophrastus as a sort of Bituminous Stone, and has therefore an affinity with the fissile slate, which has also a bituminous nature. 

Native mined — Sinopian and Lemnian Earth. German Rubrica. Native in Mines, produced by the heat of the Sun, or of the Earth. Native in Rivers, produced by the heat of the Sun, or of the Earth. When burnt. Indurated Pnigitis is made from it. Ochre is not manufactured from Rubrica, as Pliny says, but Rubrica is obtained from Ochre ... 

See Binding mechanism (Section 2.2). Technique involving induration of green agglomerate by heat. Generally, bonding at a temperature below the melting point of the main constituent by application of heat. 

The use of sintering for the induration of ceramic products (bricks, pots, vases, etc., see also Chapters 2 and 3) is quite old but through the centuries, even though empirically improved, was exclusively carried out in batch kilns. Continuous heat treatment of ceramic, powder metal, and other pre-agglomerated parts is less than 150 years old. 

Induration is a process of heating and agglomerating a clinker or pellet by grain growth and/or recrystallization. 

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