General information

Cobalt (Co) is a chem­i­cal ele­ment of Group VIII of the peri­od­ic table with atom­ic num­ber 27. In nature, it occurs as a sin­gle sta­ble iso­tope, ⁵⁹Co. Pure cobalt is a sil­very met­al with a slight­ly pink­ish tint; it is refrac­to­ry, fer­ro­mag­net­ic, and resis­tant to atmos­pher­ic cor­ro­sion. Its melt­ing point is 1495 °C, and its Curie tem­per­a­ture is 1121 °C.

In nature, cobalt is main­ly found in sul­fide, arsenide, and oxide min­er­als formed under a wide range of geo­log­i­cal conditions—from deep mag­mat­ic process­es to weath­er­ing and oxi­da­tion zones. Its occur­rence is com­mon­ly asso­ci­at­ed with nick­el, iron, and cop­per, which explains the for­ma­tion of com­plex iso­mor­phic min­er­al struc­tures. The most com­mon cobalt-bear­ing min­er­als are list­ed below:

• Pent­landite — (Fe,Ni,Co)₉S₈
• Lin­naeite — Co₃S₄
• Cobaltite — CoAsS
• Glau­codot — (Co,Fe)As
• Skut­teru­dite — (Ni,Co)As₃
• Saf­florite — CoAs₂
• Asbolane — (Co,Ni)O₂·MnO₂·nH₂O (weath­er­ing zone min­er­al)
• Ery­thrite — Co₃(AsO₄)₂·8H₂O (oxi­dized zones)

Deposit types

In nature, cobalt most com­mon­ly occurs as an acces­so­ry com­po­nent in nick­el deposits; how­ev­er, under spe­cif­ic geo­log­i­cal con­di­tions it can also form inde­pen­dent com­mer­cial con­cen­tra­tions. The main genet­ic types of cobalt deposits include mag­mat­ic, hydrother­mal, exo­genic, and strat­i­form cop­per-sand­stone deposits.

Mag­mat­ic deposits

In sul­fide Cu–Ni deposits of liqua­tion ori­gin, cobalt is a con­sis­tent com­pan­ion of nick­el. It most often occurs with­in pent­landite, where it iso­mor­phi­cal­ly sub­sti­tutes for nick­el. In most cas­es, the Co/Ni ratio in such ores is approx­i­mate­ly 1:50–1:60, and less com­mon­ly up to 1:30. Cobalt is recov­ered togeth­er with nick­el dur­ing met­al­lur­gi­cal pro­cess­ing at smelt­ing plants.

In strat­i­form deposits, par­tic­u­lar­ly in Zam­bia and the Demo­c­ra­t­ic Repub­lic of the Con­go, cobalt occurs with­in cop­per ores, enrich­ing chal­copy­rite-bear­ing hori­zons. Upsec­tion, bor­nite zones typ­i­cal­ly con­tain low­er cobalt con­cen­tra­tions. Min­er­al­iza­tion is usu­al­ly host­ed in per­me­able rocks (sand­stones, and less com­mon­ly lime­stones) and is often asso­ci­at­ed with syn­cli­nal struc­tures with­out a direct con­nec­tion to igneous intru­sions. The main cobalt-bear­ing min­er­al is lin­naeite (Co₃S₄), from which cobalt is recov­ered as a by-prod­uct.

Glob­al­ly, the largest share of cobalt reserves is con­cen­trat­ed in lat­erite deposits (48.5%), fol­lowed by strat­i­form deposits (43.1%), and sul­fide mag­mat­ic deposits (7.2%). Despite their dif­fer­ent ori­gins, most ores are mined through inte­grat­ed pro­cess­ing, which high­lights the impor­tance of cobalt as a valu­able by-prod­uct met­al.

Modern uses

His­tor­i­cal­ly, cobalt has been known since antiq­ui­ty as a pig­ment for glass, ceram­ics, and enam­els. Its salts pro­duced an intense and sta­ble blue col­or, high­ly val­ued in Ancient Egypt, Mesopotamia, Chi­na, and lat­er in Europe. Although the tech­nol­o­gy was large­ly for­got­ten in the Mid­dle Ages, it was redis­cov­ered in the 16th cen­tu­ry, and by the 18th cen­tu­ry cobalt was rec­og­nized as a dis­tinct chem­i­cal ele­ment.

In the 20th and 21st cen­turies, the impor­tance of cobalt has grown rapid­ly. It has become a key ele­ment in the pro­duc­tion of super­hard alloys (stel­lites), used for cut­ting tools, bear­ings, engine com­po­nents, and tur­bine parts. Due to its fer­ro­mag­net­ic prop­er­ties, cobalt-based alloys with nick­el, iron, and cop­per are wide­ly used in the pro­duc­tion of per­ma­nent mag­nets with high rema­nence.

Cobalt also plays a cru­cial role in elec­tro­chem­istry. Its oxides are impor­tant com­po­nents of cath­ode mate­ri­als in mod­ern lithi­um-ion bat­ter­ies used in elec­tric vehi­cles, portable elec­tron­ics, and ener­gy stor­age sys­tems. The radioac­tive iso­tope ⁶⁰Co is wide­ly applied in med­i­cine for radio­ther­a­py, as well as for ster­il­iza­tion of med­ical instru­ments and food prod­ucts.

Sig­nif­i­cant amounts of cobalt com­pounds are also used in the paint and coat­ings indus­try, ceram­ics, glass man­u­fac­tur­ing, instru­men­ta­tion engi­neer­ing, met­al­lur­gy, and catal­y­sis. For exam­ple, cobalt-based pig­ments and enam­els are high­ly val­ued for their sta­bil­i­ty and dec­o­ra­tive prop­er­ties.

On an indus­tri­al scale, cobalt is main­ly recov­ered as a by-prod­uct from copper–nickel ores. The extrac­tion process depends on the ore type. In the case of sul­fide raw mate­ri­als, flota­tion is fol­lowed by leach­ing, where­as lat­erite ores require high-tem­per­a­ture treat­ment, often under pres­sure in auto­claves.

The result­ing leach solu­tions con­tain cobalt in the form of chlo­rides or sul­fates. These solu­tions are puri­fied from impu­ri­ties such as cop­per, lead, and bis­muth through chem­i­cal pre­cip­i­ta­tion. Cobalt is then recov­ered by pre­cip­i­ta­tion or elec­trol­y­sis, pro­duc­ing crude or refined met­al with impu­ri­ty lev­els below 1–2%.

Geography of cobalt production

The glob­al geog­ra­phy of cobalt pro­duc­tion includes sev­er­al key regions that dif­fer in deposit genet­ic types, resource vol­umes, and tech­no­log­i­cal acces­si­bil­i­ty. The largest share of cobalt resources is asso­ci­at­ed with lat­erite deposits, main­ly locat­ed in the trop­i­cal belt—in Aus­tralia, Cuba, the Philip­pines, New Cale­do­nia, and Indone­sia. These deposits con­tain sub­stan­tial reserves but are char­ac­ter­ized by low cobalt grades (typ­i­cal­ly 0.05–0.1%) and require com­plex met­al­lur­gi­cal pro­cess­ing for met­al extrac­tion.

High cobalt con­cen­tra­tions are found in strat­i­form copper–cobalt deposits of Cen­tral Africa, pri­mar­i­ly in the Demo­c­ra­t­ic Repub­lic of the Con­go and Zam­bia. Here, the aver­age cobalt con­tent in ores may reach 0.3%, mak­ing these deposits high­ly com­pet­i­tive on the glob­al mar­ket. Their exploita­tion is close­ly linked to cop­per min­ing and is car­ried out main­ly through open-pit oper­a­tions.

In Cana­da, Rus­sia, Chi­na, Fin­land, and sev­er­al oth­er coun­tries, cobalt is pro­duced from mag­mat­ic sul­fide ores. In these regions, cobalt is recov­ered as a by-prod­uct of nick­el or cop­per smelt­ing. Although mag­mat­ic deposits account for less than 7% of glob­al reserves, they con­tribute up to one-third of glob­al pro­duc­tion due to high­ly effi­cient pro­cess­ing tech­nolo­gies.

In addi­tion, the role of techno­genic sources is increas­ing, includ­ing mine tail­ings, waste dumps, and slags left after long-term min­ing oper­a­tions. Such sources are active­ly exploit­ed in coun­tries with a long min­ing his­to­ry, par­tic­u­lar­ly in Europe, the Unit­ed States, and South Africa. This con­tributes to envi­ron­men­tal reme­di­a­tion of dis­turbed areas and reduces the over­all pro­duc­tion cost of cobalt.

Over­all, the cur­rent trend in the geog­ra­phy of cobalt pro­duc­tion is a shift away from high-grade but increas­ing­ly deplet­ed African deposits toward large-scale but low­er-grade lat­erite resources, as well as the devel­op­ment of tech­nolo­gies for sec­ondary recov­ery from indus­tri­al waste.

Cobalt potential of Ukraine

In Ukraine, cobalt does not form inde­pen­dent ore deposits; instead, it occurs main­ly as an asso­ci­at­ed ele­ment in nick­el ores rep­re­sent­ed by both sil­i­cate and sul­fide for­ma­tions. The main zones of such min­er­al­iza­tion are linked to the weath­er­ing crusts of hyper­b­a­sites (the Mid­dle Bug area and the Mid­dle Dnipro region) as well as endoge­nous mafic–ultramafic intru­sions (the Volyn and Azov megablocks).

Sil­i­cate ores of weath­er­ing crusts are con­cen­trat­ed in the Mid­dle Bug region (Kirovohrad region) and the Mid­dle Dnipro region (Dnipropetro­vsk region). These ores are of rel­a­tive­ly low qual­i­ty, with nick­el con­tents of 0.38–1.24%, cobalt 0.04–0.14%, and iron up to 30%. They are suit­able only for fer­ronick­el pro­duc­tion. A nick­el plant once oper­at­ed in the Bug region, pro­duc­ing over 28,000 tons of fer­ronick­el in 1995. In 1997, pro­duc­tion was halt­ed due to eco­nom­ic fac­tors. The Dnipro deposit remains unde­vel­oped due to low prof­itabil­i­ty and land-use restric­tions.

The most promis­ing endoge­nous occur­rence is the Pru­tiv­ka prospect, locat­ed with­in the Volyn block of the Ukrain­ian Shield, in the Krasnohorivka–Zhytomyr zone. The ore body is asso­ci­at­ed with a sill-like intru­sion of gab­broids, inter­sect­ed by bore­holes at depths of 150–180 m. The intru­sion has a thick­ness of 130–160 m and extends for up to 3 km. The crys­tal­liza­tion of the rocks was accom­pa­nied by frac­tion­al dif­fer­en­ti­a­tion and autometa­so­ma­tism.

The sul­fide min­er­al­iza­tion is con­cen­trat­ed in both endo- and exo­con­tact zones, with nick­el con­tents of 0.58%, cop­per 0.26%, and cobalt 0.022%. The pres­ence of plat­inum-group met­als, gold, and sil­ver has also been record­ed. The ores are char­ac­ter­ized by three par­a­ge­net­ic asso­ci­a­tions: chalcopyrite–pentlandite–pyrrhotite, pentlandite–cubanitе–chalcopyrite, and pyrite–violarite–mackinawite. The Ni/Co ratio in the ores varies from 10 to 35, which makes them com­pa­ra­ble to known deposits of the peridotite–pyroxenite–gabbronorite for­ma­tion.

In the north­ern part of the Volyn block, the Kamyanske mas­sif hosts a zone of dis­sem­i­nat­ed and vein­let min­er­al­iza­tion with cobalt con­tents up to 0.145%. The pro­ject­ed strike length of the body exceeds 6 km. Promis­ing ore occur­rences have also been iden­ti­fied in the Mid­dle Dnipro region, includ­ing the Var­varivske, Vil­nokhutirske, and Hranivske occur­rences, with cobalt con­tents up to 0.1%.

With­in the Holo­vanivsk zone (Mid­dle Bug region), the Demov’iarivske occur­rence has been stud­ied, while in the Azov region the Myko­laivske and Novotroitske occur­rences are known. Most of these are asso­ci­at­ed with ultra­ba­sic rocks or struc­tures formed dur­ing ear­ly Pro­tero­zoic tectono-mag­mat­ic acti­va­tion.

Fur­ther study of cobalt-bear­ing intru­sions of the Ukrain­ian Shield is of strate­gic impor­tance. The most promis­ing areas are those asso­ci­at­ed with mafic–ultramafic mas­sifs with­in the Volyn, Inhul, and Azov megablocks. Their for­ma­tion is linked to Pro­tero­zoic tectono-mag­mat­ic activ­i­ty (2.10–1.96 bil­lion years ago), which cre­at­ed favor­able con­di­tions for the devel­op­ment of com­plex copper–nickel–cobalt min­er­al­iza­tion.