Beryllium ores

BERYLLIUM ORES (EN: beryllium ores; DE: Beryllerze; FR: minerais de beryllium; ES: minerales de berilio; RU: бериллиевые руды) are the natural mineral formations, which are containing beryllium. Be is located within the ores mainly in the form of its own minerals, and also on the form of the isomorphic impurity (up to 1-2%) within the rock-forming minerals. The main minerals, which belong to the composition of the beryllium ore, are: beryl (14.1% of the BeO), phenakite (42-45%), bertrandite (40-42%), gel-bertrandite (32-35%), chrysoberyl (18-20%), helvite-genthelvite-danalite (10-12%), euclase (16-17%), and leucophanite (10-12%). The minerals, within the composition of which the Be may disperse in the form of the isomorphic impurities, are the idocrase (up to 1-4% of the BeO), and beryllium-margarite (up to 3%). Along the way, they extract from the beryllium ore the W, Mo, Sn, Ta, Li, Cs, Rb, and other elements, and after the beneficiation, the tailings of the beryllium ore are used as the raw materials for the ceramics and building industries.

The deposits of the beryllium ores have in most cases the endogenous postmagmatic origin, and are associated with the regions of distribution of the massifs of the leucocratic granites and sub-alkaline granitoids. There are known 7 main ore formations of the beryllium ore:

I - the beryllium-bearing granitic pegmatites (the average content of the BeO is 0.05-0.4%);

II - the phenakite-genthelvite feldspathic metasomatites within the near-fault zones among the ancient granites and gneisses (0.3-0.55%);

III - the helvite and chrysoberyl apo-skarnous greisens (0.1 - 0.3);

IV - the mica greisens and quartzous veins with beryl, rarely with bertrandite (0.1-0.15%, less often up to 1%);

V - the mica-fluorite greisens, the zones of the venules, and the mineralized zones of crushing with beryl, chrysoberyl, phenakite among the carbonatic strata, the sedimentary-metamorphic and magmatic rocks with increased basicity (0.1-0.15%);

VI - the fluorite metasomatites and feldspar-calcite venules with phenakite, bertrandite, eudidymite, and other beryllium minerals among the carbonatic rocks within the near-contact zones of the small domes of granosyenites (0.2-1.5%);

VII - the fluoritized rhyolitic tuffs with gel-bertrandite (0.4-0.7%).

The ore bodies of the beryllium ore are diverse according to their morphology: layered strata, ore stocks, columns, pipe-like depositions, steep and slightly inclined veins.

Within the USSR, there exist the deposits of the beryllium ore of almost all types. Abroad, the deposits of the beryllium ore are concentrated within the USA (Utah, Colorado, Nevada, South Dakota), Brazil (Minas Gerais), Argentina, Mexico, Republic of South Africa, Namibia, Mozambique, Zimbabwe, Uganda, Madagascar, India, Portugal. The total resources of beryllium (without the socialistic countries) are 932 thousand tonnes (1980). The share of pegmatites accounts for approximately 80% of the reserves, but there are extracted from them only 30-35% of the BeO, while there are extracted 65-70% from the fluoritized rhyolitic tuffs. The geographical distribution of the worldwide total reserves is uneven: 61% of the reserves belong to America (42% of them to Brazil, 8% to the USA and Argentina each), approximately 20% to Asia, 16% to Africa, 3% to Australia. The Western Europe is almost deprived of the beryllium ores. The extraction of the beryllium ore is concentrated mainly within the USA, Brazil, Argentina, and China. The consumption of the beryllium ore (without the socialistic countries) is estimated at 308 tonnes (1981) in terms of the extracted metal. The development is being performed prevalently by the underground method. In case of the availability within the ore of the substantial quantities of the easily flotating minerals (talc, mica), they isolate them preliminarily by flotation. For the prevention of the activation of the minerals of the waste rock, they conduct the flotation with the softened water.

It is economically feasible to process the complex beryllium ores, which are containing the minerals of Ta, Sn, W, Mo, Li. During the beneficiation of such ores, the scheme is complemented with the gravity or flotation operations. There is the cheap and effective method for the preliminary beneficiation of the beryllium ore the photoneutron separation of the ore in the form of the large lumps, which is based on the usage of the isotopic sources of the gamma-radiation; in this case, there is ensured the yield of the tailings within the limits of 25-45% of the original ore. They obtain from the quartz-feldspathic and mica-quartz-feldspathic ores the concentrates, which are containing 5-10% of the BeO with the extraction of 75-90%.

The most promising source for the obtainment of Be is the complex ores of the pneumatolytic-hydrothermal deposits, within which the beryllium minerals are represented by the bertrandite and phenakite in combination with fluorite. There have been proposed within the USA various schemes of beneficiation for the extraction of phenakite and bertrandite from such ores. There is most distributed the scheme with preliminary flotation of mica and feldspar, and with subsequent flotation of phenakite and bertrandite, the content of the BeO within the concentrate is 3-11%, the extraction is 75-90%. According to the thermal-flotation scheme, they obtain by flotation the concentrates with 18-22% of the BeO from the bertrandite ore, which is containing 1% of the BeO, after its desliming.