Phos­pho­rites. Vari­eties, dis­tri­b­u­tion, char­ac­ter­is­tics.

Phos­pho­rites are an impor­tant min­er­al resource for the agri­cul­tur­al sec­tor and there­fore have sig­nif­i­cant poten­tial in Ukraine. They are found in the form of large deposits scat­tered across dif­fer­ent regions of the coun­try. How­ev­er, their extrac­tion and use are often accom­pa­nied by envi­ron­men­tal and socio-eco­nom­ic chal­lenges. Phos­pho­rites are includ­ed in the list of min­er­als of nation­al impor­tance approved by the Res­o­lu­tion of the Cab­i­net of Min­is­ters of Ukraine dat­ed Decem­ber 12, 1994, No. 827, as agro­chem­i­cal raw mate­ri­als.

Phos­pho­rites re round lay­ered for­ma­tions of apatite found among sed­i­men­ta­ry rocks. Rocks con­tain­ing phos­pho­rites include sands, clays, sandy-clay deposits, some­times marls, cal­care­ous sand­stones, sandy chalk, lime­stones, dolomites, opokas, flints, and oth­ers. Phos­pho­rites are rep­re­sent­ed by spher­i­cal shell-like aggre­gates of apatite with radi­al-fibrous struc­ture among sed­i­men­ta­ry rocks. They often form lay­ers con­sist­ing of sep­a­rate veins or accu­mu­la­tions of phos­phates. They are main­ly used for the pro­duc­tion of min­er­al fer­til­iz­ers. The low­er lim­it of P₂O₅ con­tent in phos­pho­rites is con­ven­tion­al­ly accept­ed at 12%. The con­tent of min­er­al impu­ri­ties is vari­able and can range from 1–5% (in high-qual­i­ty deposits) to 60% (in sandy deposits).

Phos­phate min­er­als can be rep­re­sent­ed by car­bon­ate-flu­o­ra­p­atite (fran­co­l­ite), car­bon­ate-hydrox­y­la­p­atite (dahllite), flu­o­ra­p­atite, chlo­rap­atite, and oth­ers. In addi­tion to cal­ci­um phos­phate, phos­pho­rites con­tain var­i­ous non-phos­pho­rus-con­tain­ing min­er­als, among which the most com­mon are quartz, chal­cedony, cal­cite, dolomite, and glau­conite. The sec­ond most com­mon accom­pa­ny­ing min­er­als in phos­pho­rites are clay min­er­als: kaoli­n­ite, dick­ite, mont­mo­ril­lonite, and oth­ers, alu­mi­nosil­i­cate, fer­rous, and organ­ic com­pounds. Con­cre­tionary phos­pho­rites (Volyn-Podil­lia), occur­ring in native Kalush argillites and in rede­posit­ed glau­conite-con­tain­ing lay­ers, are char­ac­ter­ized by polymin­er­al com­po­si­tion. In addi­tion to phos­phates, they con­tain car­bon­ates: cal­cite, cerus­site, mala­chite; sil­i­cates: kaolin, quartz, iron and man­ganese oxides; sul­fides: gale­na, spha­lerite, chal­copy­rite, cov­el­lite, chal­cocite, pyrite, cuprite; sul­fates: barite, angle­site. In the Donet­sk region, phos­pho­rus min­er­al­iza­tion is asso­ci­at­ed with alu­mi­nosil­i­cate rocks, name­ly cran­dal­lite (CaAl[(OH)₆(PO₄)₂]*H₂O).

The total explored reserves of phos­phate raw mate­ri­als in Ukraine as of 01.01.2020 amount to 475.028 mil­lion tons, P₂O₅–15.138 mil­lion tons. The state bal­ance includes 9 deposits. Prospects for phos­pho­rite min­ing are asso­ci­at­ed with phos­pho­rite-bear­ing deposits in north­west­ern Ukraine, Mid­dle Dni­ester region, Black Sea region, and the Dnipro-Donet­sk region. The dis­cov­ered phos­pho­rite deposits are main­ly asso­ci­at­ed with glau­conite-ter­rige­nous plat­form for­ma­tion of Cre­ta­ceous-Pale­o­gene age.

Phos­pho­rite ores are divid­ed by phos­phate sat­u­ra­tion and tex­tur­al fea­tures into:

• nodu­lar (con­cre­tionary);
• gran­u­lar;
• shell-like;
• mixed;
• mas­sive micro­crys­talline.

Nodu­lar phos­pho­rites (phos­pho­rite con­cre­tions) con­sist of frag­ments of quartz, glau­conite, cal­cite, and oth­er min­er­als cement­ed by micro­crys­talline or amor­phous phos­phate. The nodu­lar type of phos­pho­rite deposits is rep­re­sent­ed by the Ratne deposit in Volyn, the deep-lying Krolevets deposit in Sumy region, the Sere­dy­na-Buda area in Sumy region, prospec­tive for­ma­tions in Kaniv Dnieper region, Mid­dle Dni­ester region, and oth­er areas. The P₂O₅ resources of phos­pho­rites in these areas exceed 100 mil­lion tons.

The most stud­ied Ratne deposit of nodu­lar phos­pho­rites is locat­ed in the north of Volyn region. Here, in the deposits of the Kyiv suite of Pale­o­gene, 14 deposits with reserves of about 10 mil­lion tons of P₂O₅ have been eval­u­at­ed. With­in the deposit, deposits of rede­posit­ed phos­pho­rites of Qua­ter­nary age have been dis­cov­ered, cov­ered by a small thick­ness of over­bur­den rocks (up to 5 m).

Besides the Ratne deposit, sev­en prospec­tive areas with phos­pho­rites in the deposits of the Kyiv suite are iden­ti­fied: Poliska, Stakhoshyn­s­ka, Pivnevs­ka, Tanyushiv­s­ka, Novoburlut­ska, Ban­ty­shevs­ka, and Zaly­manivs­ka, with a total area of 4.6 thou­sand km² and fore­cast resources of over 300 mil­lion tons of P₂O₅. The north­ern and south­ern bor­ders of the Dnieper-Donets Basin, com­posed of deposits of the Kaniv and Kyiv suites, are also promis­ing. The high­est P₂O₅ con­tents in nod­ules and peb­bles and the largest aver­age lay­er thick­ness­es were found in the areas: Kony­atyn­s­ka, Laty­shevs­ka, and Myropil­s­ka.

Gran­u­lar phos­pho­rites are rocks con­tain­ing vary­ing amounts of small grains or lay­ers of phos­phates up to 2 mm in size, cement­ed by clay-fer­rous, siliceous, or car­bon­ate cement. The gran­u­lar type of phos­pho­rite deposits is dis­trib­uted with­in the Dnipro-Donet­sk phos­pho­rite basin. Phos­pho­rite accu­mu­la­tion occurred in con­di­tions of an epi­con­ti­nen­tal basin, with phos­pho­rus com­ing from weath­er­ing crust prod­ucts of coastal parts of the con­ti­nent. In the north­ern part of the basin, semi-arid cli­mate con­di­tions exist­ed (Unecha-Sumy, Shchor­sivs­ka, Novhorod-Siver­sky, and Semenivs­ka areas). Phos­pho­rite-bear­ing deposits belong to the upper San­ton­ian. They are rep­re­sent­ed by sands sat­u­rat­ed with phos­phate grains, oolites, and small nod­ules. The pro­duc­tive hori­zon is under­lain by light gray San­ton­ian silt­stones and over­lain by chalk-marl weak­ly phos­pho­rized rocks of the Cam­pan­ian, and some­times by Qua­ter­nary sandy-clay deposits. The aver­age thick­ness of the phos­phate-bear­ing hori­zon is 2.2 m, and the P₂O₅ con­tent varies from 4 to 14%. Besides phos­phates, the hori­zon con­tains ilmenite, zir­con, rutile, anatase. The depth of the phos­pho­rite hori­zon is usu­al­ly with­in 60–140 m.

In the south­ern and south­west­ern fram­ing of the Ukrain­ian Shield, the Ceno­man­ian deposits are phos­pho­rite-bear­ing. They extend in a rel­a­tive­ly nar­row (15–20 km) strip for 1000 km. In West­ern Ukraine, phos­pho­rites occur in glau­conite-quartz and glau­conite-quartz-car­bon­ate sands and sand­stones. Pro­duc­tive deposits up to 10 m thick form the upper part of the Low­er Ceno­man­ian sec­tion. In the Lviv-Volyn depres­sion, areas with P₂O₅ con­tent of 5–8% for a thick­ness of 2.5–4.0 m and small (10–20 m) depth have been dis­cov­ered. Sev­er­al promis­ing areas are iden­ti­fied (Manevy­chi-Kle­van, Zdol­buniv-Ternopil, etc.) with fore­cast resources of 600 mil­lion tons of P₂O₅ at 5% con­tent and lay­er thick­ness of 2 m.

In the Mid­dle Left Bank of the Dni­ester, sev­er­al promis­ing areas have been iden­ti­fied: Zozul­nyt­s­ka, Khmel­nyt­s­ka, Fashchi­ivs­ka, Dunaievet­s­ka. The thick­ness of the phos­pho­rite-bear­ing hori­zon decreas­es in the south­ern direc­tion to 1 m. In some hori­zons, the P₂O₅ con­tent reach­es 12.4% for a thick­ness of 3.4 m.

Mixed phos­pho­rites are found in Albian-Ceno­man­ian deposits and are rep­re­sent­ed by phos­pho­rite nod­ules of clas­to­genic and organogenic struc­ture, as well as shell, sponge, and phy­to­mor­phic for­ma­tions. The shell type of phos­pho­rite deposits is dis­trib­uted in the Mid­dle Left Bank of the Dni­ester region.

The most typ­i­cal rep­re­sen­ta­tives of such deposits are the Zhvan and Olkhovetske deposits in Vin­nyt­sia region. The pro­duc­tive lay­er of the Zhvan deposit is rep­re­sent­ed by loose or weak­ly cement­ed quartz-glau­conite sand­stone, rarely grav­el, con­tain­ing the afore­men­tioned types of phos­pho­rites. The low­er (basal) hori­zon with a thick­ness of 0.3–4.8 m (aver­age 1.4 m) con­tains 3–10% P₂O₅ and is dis­trib­uted over an area of 15 km². The pro­duc­tiv­i­ty of the phos­pho­rite lay­er with­in the Zhvan deposit varies from 160 to 470 kg/m². The deposit has been exploit­ed on a small scale since the ear­ly 19th cen­tu­ry. Until 1913, phos­pho­rites were export­ed to Poland and Eng­land, and lat­er processed in Vin­nyt­sia.

Mas­sive micro­crys­talline (or bed­ded) phos­pho­ritesare homo­ge­neous rocks con­tain­ing micro­grains and micro­con­cre­tions of phos­phate mat­ter 0.01–0.1 mm in size, cement­ed by phos­phate-car­bon­ate or phos­phate-siliceous cement. The micro­crys­talline type of phos­pho­rite deposits is found in the quar­ries of Dokuchaievsk and Starobe­sheve dis­tricts of Donet­sk region, in deposits direct­ly over­ly­ing flux lime­stones, with two lay­ers of micro­crys­talline phos­pho­rites with a total thick­ness of 6–8 m and P₂O₅ con­tent of 6.0–10.2%. The lay­ers have a com­plex struc­ture and are iden­ti­fied based on chem­i­cal analy­ses. Macro­scop­i­cal­ly, phos­pho­rites are pale or dark gray fine-grained rocks with semi-shell frac­ture, lens­es and lay­ers of black chal­cedony, prac­ti­cal­ly car­bon­ate-free, with imprints of corals and bra­chio­pod shells.

The phos­pho­rite lay­ers are very het­ero­ge­neous, con­sist­ing of sev­er­al pack­ages of phos­phate-bear­ing rocks (0.1–0.6 m) and inter­lay­ers of car­bon­ate-siliceous and clay-siliceous shales (0.05–0.2 m). Micro­scop­i­cal­ly, two vari­eties of micro­crys­talline phos­pho­rites are dis­tin­guished:

• 1) fine-grained quartz and phos­phate form thin (up to 1 mm) alter­na­tions, with phos­phate form­ing brown grains 0.02–0.1 mm in size;
• 2) fine-grained chal­cedony, impreg­nat­ed with fine-aggre­gate phos­phate mat­ter of brown col­or.

The pres­ence of high con­tent of assim­i­l­able phos­pho­rus allows their use with­out chem­i­cal pro­cess­ing. The obtained data indi­cate prospects for dis­cov­er­ing rich fran­co­l­ite ores in the South­ern Don­bas. Deposits of the phos­phate-bear­ing zone extend along the shield slope for 120 km, lying at shal­low depths. The Stylske occur­rence of cran­dal­lite has been dis­cov­ered in their devel­op­ment zone. The prac­ti­cal val­ue of cran­dal­lite lies in the fact that it serves as a com­plex raw mate­r­i­al for phos­pho­rus and alu­minum, and cran­dal­lite ores can be processed into pure alu­mi­na and nor­mal super­phos­phate. The cran­dal­lite min­er­al­iza­tion of the Dokuchaievsk ore dis­trict, where the Stylske occur­rence is locat­ed, is sim­i­lar to for­eign indus­tri­al ana­logues.

Addi­tion­al­ly, phos­pho­rus-bear­ing rocks have been dis­cov­ered among brown iron ores rep­re­sent­ed by deposits of the Kerch Penin­su­la (AR Crimea). The deposits are local­ized in marine deposits of the Kim­mer­ian stage of the Miocene and form the Kerch iron ore basin. The ore hori­zon is con­fined to muldes, reach­ing a thick­ness of 180 m in their cen­tral parts. The ores are com­posed of hydro­fer­richlo­rite, fer­ri­mont­mo­ril­lonite, hydro­goethite (“brown” ores) or lep­tochlo­rite (“tobac­co” ores). Vivian­ite is present, caus­ing their increased phos­pho­rus con­tent. Eleven deposits are dis­tin­guished, of which the most promis­ing are Komysh-Burun, Elti­gen-Ortel, and Kyz-Aul.

The Komysh-Burun deposit is char­ac­ter­ized by reserves of about 4 mil­lion tons of P₂O₅ with an aver­age con­tent in ores of 2.09%. The Elti­gen-Ortel deposit has sim­i­lar P₂O₅ reserves with an aver­age con­tent in ores of 2.45%. These two deposits were devel­oped until 1992 by the Komysh-Burun Iron Ore Plant (annu­al ore capac­i­ty 5.7 mil­lion tons), which sup­plied fluxed agglom­er­ate.

Thus, phos­pho­rite deposits in Ukraine are an impor­tant resource that deter­mines the coun­try’s eco­nom­ic and social devel­op­ment. Their effec­tive use requires a bal­anced approach that takes into account both eco­nom­ic and envi­ron­men­tal fac­tors. The devel­op­ment of inno­v­a­tive tech­nolo­gies and a social­ly respon­si­ble approach to man­ag­ing phos­pho­rite deposits will allow Ukraine to max­i­mize their poten­tial, ensur­ing sus­tain­able growth and pros­per­i­ty for soci­ety.