Mária Tóth

Reduction of Metallurgical Wastes in an RF Thermal Plasma Reactor

Recovery of metals from iron and zinc oxides, as well as from zinc-containing metallurgical wastes, such as flue dust from the Siemens–Martin process and sludge from hot galvanizing, has been studied in an rf thermal plasma reactor under reducing conditions. The product composition was estimated by thermodynamic calculations based on the minimization of the Gibbs free enthalpy. Effects of the plate power of rf generator and the feed rate of powder on the chemical and phase composition of products have been investigated in detail. It has been proved that the rf thermal plasma treatment makes possible to produce unstable species in thermodynamic terms: metallic zinc was gained in the reaction of ZnO and hydrogen. The gradient cooling along the plasma reactor led to the segregation of the iron and zinc compounds. Valuable products were made from the particular wastes by a single step thermal plasma processing.

The provenance of “red marble” monuments from the 12th-18th centuries in Hungary

“Red marble” (Liassic-Dogger nodular limestone, ammonitico rosso ) which was mined as a decorative stone, played an important role in the art of Central Europe and especially in Hungary in the past centuries. Quarries are known from the Gerecse-Mts. (Hungary), Adnet, (Austria), Menyhaza (Romania) and Verona (Italy). Determination of the provenance of the “red marble” monuments is not feasible on the basis of petrographical methods only, because the two most typical and important Central European “red marble” occurrences (the Gerecse-Mountains, Hungary and Adnet, Austria) have the same geological age and had formed in similar environments. It is possible, on the basis of stable isotope analysis, to separate the raw material from the Hungarian and Austrian quarries; it enabled us to conduct provenance studies of archaeological objects from Hungary, Upper Hungary (present Slovakia) and Transylvania (present Romania). The results are in accordance with several historical theories, but also provide additional information on the distribution of this important artistic material.

Chemical durability of lead-bearing glazes in sulphuric acid solutions — Laboratory experiments performed on Zsolnay architectural ceramics from Budapest (Hungary)

ABSTRACT This study aims to simulate the long-term deterioration of architectural glazes exposed to open air in a highly polluted urban environment. A laboratory experiment—a 14-day long accelerated weathering test—on glazed roof tiles has been performed to reveal the damaging influence of contacting acid solutions originating from dissolved gaseous pollutants, mainly SO2. The studied tiles are made by the Hungarian Zsolnay factory and applied on two buildings in Budapest in the 19th and 20th century. The ceramics were covered mainly by lead glazes in the construction and lead-bearing alkali glazes in the renovation periods. The solution of pH2 induced a greater dissolution, especially of alkali and alkaline earth metals (up to 2886 ppm), but less lead (up to 21 ppm) from the lead glazes of the construction periods. Newly formed lead sulphate (anglesite) on the corroded glaze parts precipitated on some lead-bearing alkali glazes, with moderate dissolution of alkali and alkaline earth metals (up to 396 ppm) accompanied by higher amount of lead (28–39 ppm). Based on the results, the main determining factor in the durability of glazes is mostly their chemical composition and less their preliminary degradation state.

Scythian Age settlement near Nagytarcsa

This paper deals with the archaeological material of a Scythian Age settlement excavated near Nagytarcsa in 2007. Located on the higher terrace of a stream, the site represents a characteristic lowland, hamlet-like settlement of the Vekerzug culture, where animal husbandry played an important role in subsistence. Based on diagnostic ceramic finds and radiocarbon dating the settlement can be assigned to the Ha D2 period. The archaeological description, as well as the evaluation of settlement features and finds, is supplemented with a detailed petrographic analysis with an emphasis on wheel-thrown and Hallstatt type ceramics. The petrographic and geochemical analysis of the sherds and sediments collected on the site aim to confirm archaeological interpretations in order to determine the provenance of the ceramics and to assess whether their technological characteristics suggest specialization in production.

Characterization of particulate matter in attic and settled dusts collected from two buildings in Budapest, Hungary

Abstract We have investigated two buildings covered with Zsolnay glazed architectural ceramics in Budapest (Hungary), one located in the densely built-up area of the city centre with a high traffic rate and one in a city quarter with moderate traffic and more open space. A black crust layer, containing a large amount of artificial particulate matter with different size and chemical composition, was observed on the ceramic material of both buildings, whereas weathered glaze was detected only on the ceramics of the building situated in the city centre. In this paper, our goal is to reveal the role of the particulate matter in the degradation of architectural ceramics. For this reason the attic dust and settled dust from the roofs of the studied buildings were collected. In the attic dust, besides the natural particles of geological origin, three types of artificial particles typically with spherical shape (spherules) were also distinguished: aluminosilicate (two subtypes), carbonaceous, and iron-rich fly-ash. The appearance of gypsum crystallites around the particulate matter in association with all spherule types suggests that the particulate matter greatly contributes to the degradation process.

The tin content of the blue-glazed hutterite and haban ceramics-implications for the production technology based on results of the handheld XRF and electron microprobe analyses

The Hutterites and Habans produced coloured-glazed, mostly blue- and yellow-coloured vessels alongside their white-glazed faience ware. However, the production technology of the coloured-glazed vessels, specifically the nature of the glaze, is a matter of debate among scholars. Both coloured tin glaze and coloured engobe covered with a transparent lead glaze were thought to have been applied on the ceramics. Around 140 objects of blue-glazed Hutterite and Haban museum objects and archaeological artefacts were analysed using a handheld XRF spectrometer. In addition, small fragments of selected ceramics were studied by electron microprobe analysis (EMPA). According to the XRF measurements the blue glaze of all except one of the studied Hutterite and Haban ceramics contains tin in variable amounts (from about 0.015 wt% up to 13 wt%). The EMPA technique showed that tin in the form of tin oxide opacifier was deliberately added to the single-layered alkali– lead or lead–alkali glaze. These data confirm that the tin glaze technique was used during production of blue-glazed ceramics, and in this respect they can be regarded as faience. The blue glaze of the Haban vessels produced by a “mining town” workshop contains tin in very low concentrations (Sn <0.2 wt% by XRF), therefore the opacity of the glaze is mainly caused by the abundant silica and arsenate particles.

Examination of Haban vessels with uranium-bearing blue glaze

From the mid-15th century “berettino”, or “turchino”, lighter and darker, deep blue, cobalt-bearing glazes were used on Italian maiolica objects. At first such vessels were made mainly in Faenza, later they spread to Northern Italy and from the 17 th century they became popular throughout Europe. According to written sources and archaeological finds, potters working in the Anabaptist-Hutterite settlements used blue glaze right from the start. From the second half of the 17 th century there was an increase in the quantity of light and dark blue vessels that were made in many places. In the course of archaeometric research using a handheld X-ray fluorescence spectrometer (XRF), more than 500 Hutterite and Haban objects were analysed; of these circa 140 had a blue glaze. The measurements made on blue glazes and decorations found uranium in addition to cobalt in 107 objects. Some of the 17 th century vessels and stove tiles were made in Alvinc (Vinţu de Jos, Romania), Sarospatak, and probably in Szobotist (Sobotiste, Slovakia). The vessels with a blue or a white glaze, generally painted roughly with a brush, form a characteristic group provisionally attributed to a “mining town workshop”. Their production began at the end of the 17 th century and was passed on by tradition until the 1780s. The workshop probably operated in the vicinity of a mining town in the former Zolyom county, along the upper reaches of the Garam river, in the vicinity of Besztercebanya (Banska Bystrica, Slovakia).