Foundry sands (SiO2 content >96%) with a low content of alcalic pollutants which are characterize by a high sintering temperature, are the basic raw material for preparing moulds and cores masses (up to 90% of these masses) used in steel castings, iron castings and castings made of metals alloys. For making the steel castings the sands have to be characterized by the sintering temperature of 1,400°C, for the iron castings – 1,350°C, and for the non-ferrous metals castings - 1,200°C. Two types of foundry sands are differentiated on the basis of the cement and carbonates content: pure quartz sands and natural binder (cement) foundry sands. The raw material coming from some of foundry sands deposits can also be used in other applications. Pure quartz sands are used as glass sands or sometimes as sands for building and road industries.
Deposits of Polish foundry sands are situated mainly in the central and southern parts of the country and usually have the form of sand sheet deposits (map). The sand deposits are of the Quaternary, Miocene, Cretaceous and even Jurassic and Triassic age. In the vicinities of Częstochowa, foundry sands of a natural binder occur in infills of the karst forms developed in Upper Jurassic limestones, forming small natural sand deposits of a varying thickness. Foundry sand deposits located in the area between Gorzów Śląski and Żarki are represented by fine- to medium-grained sands and sandstones of the Lower Jurassic age. In turn, weakly cemented sandstones or locally loose sands of the Middle Jurassic age form foundry sand deposits found in the vicinities of Szydłowiec, Wąchock, Skarżysko-Kamienna and Jagodna as well as Opoczno and Iłża. Cretaceous sands are known mainly from the Tomaszów Basin (where they co-occur with those of glass sands) as well as from the Bolesławiec Basin and the vicinities of Krzeszówek in the Lower Silesian region. Tertiary foundry sands represented by deposits of a land environments origin occur in the Konin area, at the margin of the Holy Cross Mts. and in Pomerania, and those of a marine origin occur in the Lublin Upland. In northern Poland mainly the Quaternary age sands occur – these are sediments of dune fields or fluvioglacial terrace accumulations.
Anticipated economic resources of foundry sands decreased due to the output and losses by 1.13 million tonnes and amounted to 301.84 million tonnes in 2018. On the application of the Marshall of Dolnośląskie Voivodeship, Bolesław deposit with zero resources was crossed out from “The balance..” in 2018.
Anticipated economic resources of exploited deposits are covered by the detailed exploration (categories A, B and C1) and are equal 49.60 million tonnes accounting for 16.4% of total anticipated economic resources.
Table 1 shows resources and the state of development and exploration of foundry sands in Poland.
Economic resources of foundry sands increased by 4.12 million tonnes (22.7%) in comparison with 2017 – in spite of the exploitation and losses – due to the formal restoration of economic resources of Krzeszówek and Zawisna II deposits. For Krzeszówek deposit the exploitation concession was maintained in force, while for Zawisna II deposit in 2018 there was the exploitation concession issued for a new concession holder.
The output of foundry sands in Poland amounted to 1,046 thousand tonnes in 2018 and increased by 23.41 thousand tonnes in comparison with the previous year. It was the first year of the slight output growth after three consecutive years of its declining. The production volume dropped from: Grudzeń-Las deposit (by 19.82 thousand tonnes) and Ludwików Pole B-1 deposit (by 16.8 thousand tonnes), whereas the output increased from Szczakowa deposit (by 47.49 thousand tonnes) and the exploitation from Ludwików – Pole B restarted (12.54 thousand tonnes).
The figure given below shows changes in domestic resources and production of foundry sands in Poland in the years 1989-2018.
Prepared by: Agnieszka Malon