Pelletization


Also found in: Dictionary, Wikipedia.

pelletization

[pel·əd·ə′zā·shən]
(mining engineering)
Forming aggregates of about ½-inch (13-millimeter) diameter from finely divided ore or coal.

Pelletization

 

the process by which pellets are formed in drum, pan or conical granulators by the action of water on particles of ore or concentrate.

The surface tension of the thin film of water on the particles of ore produces the compressing effect, while the water that seeps by capillary action into the spaces between the particles binds the particles by negative capillary pressure. The strength of this binding effect depends primarily on the size and shape of the particles but also on the surface properties and wettability of the ore.

The consolidation of the particles into a pellet of the required size in the granulator is analogous to the formation of a snowball. The cohesive strength of the resulting pellets is proportional to the hydrophilicity and degree of dispersion of the particles. After pelletization, the pellets are hardened by roasting, during which ceramic bonds form between the particles or during which the particles are consolidated as a result of softening. Roasting is conducted in shaft furnaces, conveyer and ring roasting machines, and combined tube-grid furnaces. The annual output of roasting machines is from 0.5 to 5 million metric tons.

The pelletizing process was first proposed in the 1920’s. The first industrial pelletizers were constructed in the USA between 1945 and 1955. In 1973 the annual world capacity for the production of roasted pellets reached 150 million metric tons.

REFERENCE

Berezhnoi, N. N., G. V. Gubin, and L. A. Drozhilov. Okomkovanie tonkoizmel’chennykh kontsentratov zheleznykh rud. Moscow, 1971.

E. N. IARKHO

Mentioned in ?
References in periodicals archive ?
gasification, pelletization, and torrefaction) have been developed for biomass energy production, and most have fuel feedstock specifications (e.
Iran could also fabricate UO2 pellets for VVER fuel assemblies in advance of making assemblies and loading and irradiating the fuel in a power reactor, as the UO2 would be chemically stable after pelletization.
The company has set up three beneficiation plants near its mines at Goa to process the low grade ore to a high grade and also has Pelletization plant of 1.
After the pressure sensitive matrix and poly film waste streams are delivered they are chopped and mixed in preparation for pelletization.
The direct pelletization process called "CPS[TM]" is an advanced fluid bed rotor technology that allows many API's to be spheronized into matrix pellets having a remarkably uniform bead diameter and having a dense, smooth surface that is ideal for the application of functional coatings.
Various methods of disposal have been tried such as waste pelletization, composting, vermiculture, incineration with and without energy recovery, anaerobic digestion, and biogas generation from garbage, pyrolysis and sanitary landfills.
Corkins and VSHI developed a persuasive statewide plan to develop Vermont's 100,000 acres of underutilized land to grow prairie grass for a revolutionary grass pelletization fuel system.
The high costs of pelletization can be justified by better operability of the fuel (handling, transportation, storage, and feeding), resulting in improved boiler and combustion performance.