Dolomites. Prop­er­ties, ori­gin, and uses

Dolomite is a wide­ly dis­trib­uted min­er­al rock that is an impor­tant resource in var­i­ous indus­tries. The min­er­al is named after French geol­o­gist Déo­dat Gratet de Dolomieu, who first described it in the 18th cen­tu­ry.

General Characteristics

Dolomite is a car­bon­ate min­er­al with the chem­i­cal for­mu­la CaMg(CO₃)₂, con­sist­ing of cal­ci­um, mag­ne­sium, and car­bon­ate ions. It can be con­sid­ered an ana­logue of lime­stone, but with a high­er mag­ne­sium con­tent. It is usu­al­ly white, gray, and some­times slight­ly pink or yel­low­ish. Dolomites occur as mas­sive rocks pri­mar­i­ly com­posed of the dolomite min­er­al.

Dolomites are list­ed as min­er­als of nation­al sig­nif­i­cance by the res­o­lu­tion of the Cab­i­net of Min­is­ters of Ukraine from Decem­ber 12, 1994, No. 827, clas­si­fied as refrac­to­ry raw mate­ri­als, flux raw mate­ri­als, and stone for con­struc­tion pur­pos­es.

Dolomites are formed in sev­er­al ways. Pri­ma­ry dolomites are deposit­ed under marine con­di­tions, where mag­ne­sium-rich sea­wa­ter replaces cal­ci­um in lime­stone deposits with mag­ne­sium. This process is called dolomi­ti­za­tion. Sec­ondary dolomites form through the replace­ment of cal­cite with mag­ne­sium at lat­er stages of the geo­log­i­cal cycle. Sec­ondary dolomites form under high-tem­per­a­ture and pres­sure con­di­tions, where lime­stone can trans­form into dolomite rock enriched with mag­ne­sium.

Physical and Chemical Properties

Dolomite has a hard­ness of 3.5 to 4 on the Mohs scale, mak­ing it soft­er than quartz but slight­ly hard­er than lime­stone. The den­si­ty of dolomite ranges from 2.8 to 2.9 g/cm³, which is sim­i­lar to oth­er car­bon­ate rocks. Dolomite is less sol­u­ble in water than cal­cite and less prone to chem­i­cal weath­er­ing, mak­ing it more resis­tant under cer­tain con­di­tions. Dolomite has char­ac­ter­is­tic bire­frin­gence, which can be used for its iden­ti­fi­ca­tion under a micro­scope.

Uses of Dolomite

Dolomite is a min­er­al with a wide range of uses, from con­struc­tion and agri­cul­ture to envi­ron­men­tal con­trol and glass pro­duc­tion. Its unique phys­i­cal and chem­i­cal prop­er­ties and diverse appli­ca­tions make it a valu­able nat­ur­al resource. The devel­op­ment of tech­nolo­gies allows for the expan­sion of dolomite’s uses each year, increas­ing its sig­nif­i­cance in indus­try and the econ­o­my.

Dolomite is used as a con­struc­tion mate­r­i­al in the form of crushed stone for road con­struc­tion, rail­way foun­da­tions, and in the pro­duc­tion of con­crete mix­tures. It is also used as raw mate­r­i­al for cement and lime pro­duc­tion. The pres­ence of mag­ne­sium pro­vides addi­tion­al strength to build­ing mate­ri­als. Dolomite is used as a flux in glass­mak­ing to low­er the melt­ing point and improve the qual­i­ty of the glass. The mag­ne­sium in dolomite enhances the ther­mal resis­tance of fin­ished glass. Dolomite flour is a min­er­al fer­til­iz­er used to reduce soil acid­i­ty and increase fer­til­i­ty. It also improves soil struc­ture and pro­vides mag­ne­sium, which is essen­tial for pho­to­syn­the­sis in plants. Dolomite is used as a flux in iron and steel smelt­ing to remove impu­ri­ties and improve the qual­i­ty of the met­al. It is also used in the pro­duc­tion of mag­ne­sia, a refrac­to­ry mate­r­i­al for blast fur­naces. It is also used as a raw mate­r­i­al for pro­duc­ing var­i­ous chem­i­cal com­pounds, such as mag­ne­sium oxide (MgO) and cal­ci­um oxide (CaO), which are used in the pro­duc­tion of fer­til­iz­ers, paints, cos­met­ics, and med­i­cines. Dolomite slabs are used for build­ing facades, dec­o­ra­tive ele­ments, and in land­scape design. Dolomite is used to neu­tral­ize acidic waste in indus­tri­al process­es. It is also used in water purifi­ca­tion as it can absorb harm­ful sub­stances and reg­u­late pH lev­els.

Main Dolomite Deposits in Ukraine

In the Donet­sk region, three deposits and two account­ing objects have been devel­oped. Most of the reserves and the entire pro­duc­tion of dolomite for met­al­lur­gy are con­cen­trat­ed in the South­ern Don­bass. Dolomites are part of the Low­er Car­bonif­er­ous car­bon­ate for­ma­tion 300–450 m thick, extend­ing in a sub-lat­i­tu­di­nal direc­tion for about 50 km par­al­lel to the junc­tion of the Don­bass and the Azov part of the Ukrain­ian Shield. In the Vol­no­vakha zone are locat­ed the Novotroitske, Olenivske, Stilske, Karakub­ske, Pivnich­no­shevchenkivske deposits, as well as promis­ing objects (Per­shotravnevyi, Rod­nykivskyi). Here, car­bon­ate and sandy-clayey rocks alter­nate, with the Tour­naisian for­ma­tion being almost entire­ly car­bon­ate. Car­bon­ate rocks include flux lime­stones, dolomi­tized lime­stones, and dolomites. Due to the devel­op­ment of karst process­es at deep­er hori­zons, the qual­i­ty of raw mate­ri­als wors­ens. As of 1999, the bal­ance reserves of dolomite in Don­bass in cat­e­gories A+B+C were 247.2 mil­lion tons.

In the Zakarpat­tia region, the Kuzynske deposit has been thor­ough­ly explored and is locat­ed near the vil­lage of Dilove. The use­ful min­er­al here is con­fined to the Kuzyn­s­ka suite, form­ing a lens-like deposit stretch­ing 2.5 km, with max­i­mum thick­ness­es of 260–320 m.

In Dnipropetro­vsk, the Dovhyntsivske dolomite deposit is well-known. It is one of the deposits where dolomite with a high mag­ne­sium con­tent is mined. Dolomite from this deposit is main­ly used in met­al­lur­gy and con­struc­tion due to its good flux prop­er­ties.

In Ternopil, near the vil­lage of Zavadi­v­ka, high-qual­i­ty Mid­dle Devon­ian dolomite deposits (Zavadi­vske deposit) are found. The chem­i­cal com­po­si­tion and phys­i­cal prop­er­ties of these dolomites allow them to be used in many indus­tries, par­tic­u­lar­ly glass and met­al­lur­gy, but the sig­nif­i­cant dis­tance from rail­roads and con­sumers hin­ders their devel­op­ment, and they are main­ly used for road con­struc­tion and par­tial­ly for the pro­duc­tion of fac­ing tiles.

In Zhy­to­myr, the Negre­bivske com­plex deposit of dolomites, gran­ites, gneiss­es, peg­matites, and amphi­bo­lites is being devel­oped. The dolomites extract­ed here are suit­able for the glass indus­try, the pro­duc­tion of fac­ing blocks and slabs, and the accom­pa­ny­ing pro­duc­tion of dec­o­ra­tive grav­el, sand, and flour for lim­ing acidic soils. The dolomite reserves are esti­mat­ed at 12,467 thou­sand cubic meters.

In con­clu­sion, dolomite is a car­bon­ate min­er­al wide­ly used in indus­try due to its unique phys­i­cal and chem­i­cal prop­er­ties. It is used in con­struc­tion, met­al­lur­gy, agri­cul­ture, the glass indus­try, and the chem­i­cal indus­try. Ukraine has sig­nif­i­cant deposits of dolomite, par­tic­u­lar­ly in the Donet­sk, Zakarpat­tia, Dnipropetro­vsk, and Ternopil regions. Its high qual­i­ty makes dolomite a valu­able resource for the pro­duc­tion of build­ing mate­ri­als, fer­til­iz­ers, and glass.