Laterite


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laterite

[′lad·ə‚rīt]
(geology)
Weathered material composed principally of the oxides of iron, aluminum, titanium, and manganese; laterite ranges from soft, earthy, porous soil to hard, dense rock.

Laterite

 

red ferruginous or ferruginous-aluminiferous eluvial formations typical of humid tropical and subtropical regions. The term “laterite” was first proposed by the English geologist F. Buchanan in 1807 to designate the red ferruginous rocks of the weathering mantle, used in India and other countries to make bricks used in construction. Later the term came to be used for a group of red rocks that differed in composition and origin. In soil science “laterite” is often used to denote ferruginous soil horizons of infiltrative origin. Climate is the chief factor in tropical weathering. Laterite forms only in tropical and subtropical regions with more than 1,300–2,000 mm of average annual precipitation and mean annual temperatures of 20°-30° C. The laterites overlie aluminosilicate rocks of various composition and form through laterization, during which up to 90 percent of the SiO2 and bases (of their total content in the parent rock) are removed.

In the tropical zone of the globe laterites cover vast plateaus and hilly areas. Their thickness ranges from a few meters to 50 m. Their age varies from Jurassic to Recent.

In the USSR residual and redeposited laterites of Mesozoic and Cenozoic age are found in the Ukraine, Kazakhstan, Siberia, the Urals, and in Middle Asia. Abroad the development of laterite of Recent (Anthropogene) age has been proved in the Democratic Republic of Vietnam and on Pacific islands (Hawaii, Samoa, Tahiti).

Various minerals are associated with laterites, including aluminum, iron, manganese, nickel, and other ores (Cuba, New Caledonia) and very large bauxite deposits (Guinea, Ghana). In India laterite is used to make bricks used in construction.

REFERENCES

Laterity: Sb. st. Moscow, 1964.
Glinka, K. D. Pochvovedenie, 6th ed. Moscow, 1935.
Fridland, V. M. Pochvy i kory vyvetrivaniia vlazhnykh tropikov. Moscow, 1964.
Bushinskii, G. I. Geologiia boksitov. Moscow, 1971.
Fox, C. S. Bauxite and Aluminous Laterite. London, 1932.

N. A. LISITSYNA and V. P. PETROV

References in periodicals archive ?
The laterite soil and pressmud were air-dried at room temperature in 2 weeks and then were pulverized to pass through 1 mm sieve once again.
Since the laterite was limonitic type the main iron mineral was goethite (FeOOH).
The mineralised laterite extends from surface to a depth of 55m and is underlain by weathered mafic/ultramafic rocks.
Australia has an abundance of nickel laterites, so it would provide a significant boost to our economy," Dr Robinson said.
Kaolinite clay group, including kaolinite, gibbsite, boehmite, dickite and nacrite, is abundantally present in laterite / bauxite facies of the study area.
Laterite or laterized concrete on the other hand has attracted the attention of many authors and researchers.
Laterite is a residual product of rock decay that is red in color and has high content in the oxides of iron and hydroxide of aluminum.
Presenters at technical conferences over the past few years have highlighted laterite ore processing challenges, which include high energy requirements involving both heat and pressure, high consumption of expensive reagents and sulphuric acid, and environmental risks, to name just a few.
The topics discussed include smelting laterite concentrates to sulfide matte, extracting nickel and cobalt from sulfide ores, the slow cooling and solidification of converter matte, extracting cobalt from nickel laterite and sulfide ores, and smelting and converting sulfide concentrates containing platinum-group metals.
7% in British nickel laterite developer ENK Plc (LON:ENK; ASX:ENK) under their joint takeover bid.
The Direct Nickel (DNi) Process is a hydrometallurgical process for nickel laterite deposits.
LN), a London-based mid-tier nickel laterite producer, has received an environmental permit for the Acoje joint venture project with Rusina Mining NL (RML.