Brick and tile raw mate­ri­als are the basis for the pro­duc­tion of build­ing bricks, tiles and oth­er types of rough ceram­ics. The main type of raw mate­r­i­al is low-melt­ing loams — plas­tic clay rocks, which are well formed, dry and fired with­out the for­ma­tion of cracks. They con­tain clay min­er­als, frag­ments of quartz, feldspars, mica, as well as car­bon­ates and oth­er impu­ri­ties.

Brick and tile raw mate­ri­als are includ­ed in the list of min­er­als of nation­al impor­tance, approved by by the res­o­lu­tion of the Cab­i­net of Min­is­ters of Ukraine dat­ed Decem­ber 12, 1994 № 827

Varieties of brick and tile raw materials

Brick and tile raw mate­ri­als are rep­re­sent­ed by a wide range of sed­i­men­ta­ry rocks that have the nec­es­sary prop­er­ties for the pro­duc­tion of ceram­ic build­ing mate­ri­als. The main types include les, clay, silt, silt­stone, argillite and shales.

Les — is a loose, yel­low­ish-gray rock with high poros­i­ty, formed by the aeo­lian (wind) path­way. Con­sists main­ly of dusty par­ti­cles (0.05–0.005 mm) cement­ed with cal­ci­um car­bon­ates. Loess loams are char­ac­ter­ized by a high­er pro­por­tion of clay frac­tions and often con­tain impu­ri­ties of gyp­sum or lime.

Clay — is the most com­mon type of raw mate­r­i­al, which is char­ac­ter­ized by high plas­tic­i­ty, the abil­i­ty to hold the shape after form­ing and form a strong shard after fir­ing. It is used both inde­pen­dent­ly and in a mix­ture with oth­er com­po­nents.

Aleu­rite — is a sed­i­men­ta­ry rock con­sist­ing of par­ti­cles mea­sur­ing 0.01–0.05 mm and inter­me­di­ate between sand and clay. It has good con­nec­tiv­i­ty and is suit­able for form­ing prod­ucts after appro­pri­ate pro­cess­ing.

Aleu­ro­lite — is a dense cement­ed vari­ety of silt­stone, often accom­pa­nied by clay rocks. After grind­ing, it can be used as an admix­ture to clay mix­tures to improve the mass struc­ture.

Argillite — is a com­pact­ed clay rock with high dry strength. It is often used as a com­po­nent of com­pos­ite mix­tures for brick pro­duc­tion, espe­cial­ly in weath­er­ing zones.

Slan­ets — thin-lay­ered meta­mor­phosed or sed­i­men­ta­ry rock, which dur­ing grind­ing can be used in mix­tures with clay to reg­u­late the plas­tic­i­ty and ther­mo­phys­i­cal prop­er­ties of future prod­ucts.

Quality characteristics of brick and tile raw materials

The qual­i­ty of bricks depends not only on the raw mate­ri­als, but also on the man­u­fac­tur­ing tech­nol­o­gy. The best results are giv­en by loams, which, after fir­ing at 900‑1000°C, form a strong, frost-resis­tant shard. If nec­es­sary, quartz sand, ham­mer bricks or slags are added to loams to reg­u­late plas­tic­i­ty and reduce shrink­age.

The most impor­tant prop­er­ty of plas­tic loams and most clays is their stick­i­ness —, the abil­i­ty to par­tial­ly melt at tem­per­a­tures below the refrac­to­ry tem­per­a­ture, and after cool­ing to form a dense mass (skull) with a poros­i­ty that ensures water absorp­tion of no more than 8 %.

Some clays, argillites and shales have an intu­mes­cence — abil­i­ty under the short-term action of a tem­per­a­ture of 1200–1250°С to increase in vol­ume and form par­ti­cles with a porous core and a vit­re­ous fused sur­face.

The smooth­ness of clay mass­es, rel­a­tive­ly low sin­ter­ing tem­per­a­tures of ceram­ic shards and swelling ensure the wide use of clay rocks in var­i­ous indus­tries. The most wide­ly fusible clays are used in the con­struc­tion indus­try for the pro­duc­tion of wall build­ing mate­ri­als (ceram­ic brick and stone), light ceram­ic fillers for con­crete, Port­land cement, ceram­ic pipes, tiles, tiles.

In addi­tion, the fol­low­ing prop­er­ties of loams are impor­tant for the pro­duc­tion of high-qual­i­ty prod­ucts: plas­tic­i­ty, stick­i­ness, fire resis­tance, gran­u­lo­met­ric com­po­si­tion, con­tent of dye oxides, mois­ture and shrink­a­bil­i­ty. Mod­er­ate plas­tic loams with a low con­tent of lime and iron oxides are con­sid­ered opti­mal for the pro­duc­tion of build­ing bricks. An exces­sive amount of car­bon­ates, in par­tic­u­lar in the form of lime­stone inclu­sions, dete­ri­o­rates the qual­i­ty of prod­ucts.

Brick and tile raw mate­ri­als are the basis for the pro­duc­tion of build­ing bricks, tiles and oth­er types of rough ceram­ics. The main type of raw mate­r­i­al is low-melt­ing loams — plas­tic clay rocks, which are well formed, dry and fired with­out the for­ma­tion of cracks. They con­tain clay min­er­als, frag­ments of quartz, feldspars, mica, as well as car­bon­ates and oth­er impu­ri­ties.

The fol­low­ing prop­er­ties of loams are impor­tant for the pro­duc­tion of high-qual­i­ty prod­ucts: plas­tic­i­ty, stick­i­ness, fire resis­tance, gran­u­lo­met­ric com­po­si­tion, con­tent of dye oxides, mois­ture and shrink­a­bil­i­ty. Mod­er­ate plas­tic loams with a low con­tent of lime and iron oxides are con­sid­ered opti­mal for the pro­duc­tion of build­ing bricks. An exces­sive amount of car­bon­ates, in par­tic­u­lar in the form of lime­stone inclu­sions, wors­ens the qual­i­ty of prod­ucts.

Industrial stocks of brick and tile raw materials

In Ukraine, reserves of brick and tile raw mate­ri­als are con­cen­trat­ed in areas of wide dis­tri­b­u­tion of clay rocks and occu­py a sig­nif­i­cant place among the deposits of almost all geo­log­i­cal groups in almost all geostruc­tur­al regions: the Dnipro-Donet­sk depres­sion and the fold­ed region of Don­bas, on the Ukrain­ian shield and its slopes, the Volyn-Podil­s­ka plate, in the Lviv depres­sion, the Carpathi­an fold­ed region, the Black Sea depres­sion and the Crimean fold­ed region.

The state bal­ance of min­er­als of Ukraine takes into account 1,844 clay deposits, includ­ing 51 com­plex ones, the bal­ance reserves of which are 2,410 mil­lion m³, and off-bal­ance — 89 mil­lion m³ (table. 1). Their raw mate­ri­als are suit­able for the pro­duc­tion of bricks, tiles, pot­tery and majoli­ca, fac­ing tiles and ceram­ic drainage pipes. Most of the deposits are small with reserves of up to 1,000 thou­sand m³. Of the medi­um and large deposits, 865 are being devel­oped and 21 deposits are being pre­pared for devel­op­ment.

In Zhy­to­myr region, the Andrushiv­ske deposit is known, which con­tains loams with good form­ing prop­er­ties, which give high-qual­i­ty bricks with good strength and frost resis­tance. And in the Donet­sk region, mud­stones of the weath­er­ing zone are wide­ly used, and in the Carpathi­ans and Podil­la — var­ie­gat­ed clays of Neo­gene age.

There are 51 deposits of loams and clays suit­able for mak­ing bricks in the Rivne region; their indus­tri­al reserves amount to about 350 mil­lion m³. In the 1990s, 38 deposits were devel­oped, 36 brick fac­to­ries oper­at­ed, where 223 mil­lion bricks were pro­duced. Pro­vid­ed that brick fac­to­ries are used as much as pos­si­ble, tak­ing into account the recon­struc­tion of some of them and the intro­duc­tion of new capac­i­ties, they are pro­vid­ed with raw mate­ri­als for more than 30 years.

In the Kyiv region, the best raw mate­r­i­al for brick pro­duc­tion is marl clay of the Kyiv world and the silt­stone of the Pale­o­gene Obukhov world lying on it with a total thick­ness of about 30 m. In total, there are more than 74 deposits of brick and tile raw mate­ri­als of the pre-Qua­ter­nary age in the ter­ri­to­ry of the Kyiv region, 12 of which are being devel­oped. These are Mostyshchenske‑I,II, Zabuchske, Kreny­chske, Obukhivske‑I,II, Zarichanske and oth­ers.

So, brick and tile raw mate­ri­als — are nat­ur­al clay rocks that have long been used for the man­u­fac­ture of bricks, tiles and oth­er build­ing mate­ri­als. Its main advan­tage is plas­tic­i­ty in the raw state and the abil­i­ty to hard­en after fir­ing. Due to its min­er­al com­po­si­tion, in par­tic­u­lar the pres­ence of clay min­er­als and oxides, such raw mate­ri­als pro­vide the nec­es­sary strength, den­si­ty, resis­tance to frost and mois­ture. The prop­er­ties of the fin­ished prod­uct depend on the spe­cif­ic deposit, the fir­ing mode and the com­po­si­tion of the mix­ture, to which sands or man-made impu­ri­ties can be added. Ratio­nal use of local raw mate­ri­als in com­bi­na­tion with mod­ern tech­nolo­gies allows to pro­duce high-qual­i­ty mate­ri­als with min­i­mal envi­ron­men­tal impact.