M.M. Jordan

Firing transformations of cretaceous clays used in the manufacturing of ceramic tiles

Abstract Mineralogical transformations caused by firing, of five different compositions used in the formulation of ceramic pastes have been studied. Test samples have been prepared by extrusion and fired in the range of 900–1150°C. Analysis of the fired samples was carried out by optical microscopy. The presence of enstatite, gehlenite, hercynite and mullite and abundant vitreous phase showed neomineralization. A fluid texture was present in all the samples and phenocrysts occurred in the partially microcrystalline matrix. In this way, the ceramic ware was analogous to porhyritic type rocks, with quartz phenocrystals and a typical undulating liquidation, opaque minerals such as hematites and crystalloblastic quartz structures on grains of orthoclase. The samples with low carbonate contents were composed of bulky particles, predominantly of quartz and hematites, which are agglomerated in a vitreous matrix.

Firing transformations of Tertiary clays used in the manufacturing of ceramic tile bodies

The mineralogical transformations during the firing of six different raw materials used in ceramic tile manufacturing have been studied. Test samples have been prepared by extrusion and fired in the range of 800–1150°C. Analysis of the fired samples was carried out by X-ray diffraction (XRD). The presence of augite, gehlenite, hematite, spinel, wollastonite and abundant vitreous phase showed neomineralization. Mixtures of illitic clays containing abundant CaCO3 form gehlenite, wollastonite and anorthitic plagioclases above 950°C. Samples poor in CaCO3 give a simple mineralogical composition of quartz and hematite.

Microbial recolonization and chemical changes in a soil heated at different temperatures

Samples of a Mediterranean forest soil were exposed in a muffle furnace to seven temperatures (100–700°C) for 15 min to simulate different fire intensities. Heated soils were incubated for 100 days after re-inoculation with fresh unheated soil. Immediately after heating, the extractable organic C increased with the heating temperature, reaching a maximum at 400°C. This increase in extractable organic C and nutrients in soils heated below 400°C allowed a rapid recolonization of bacteria, increasing the basal respiration. During the 100-day incubation, the cumulative values of basal respiration and carbon mineralization rates generally followed a double exponential equation in unheated and heated samples. Heating at 200°C caused a reduction of 99.6% for fungi (measured as culturable fungal propagules), which showed lower recolonization capacity than that of bacteria. Heating also caused a decrease in the organic C content of the soils, especially for the highest temperatures. As a consequence, the microbial biomass carbon recovery was short lived in heated soils. The varied effects of heating and incubation on the inorganic and organic nitrogen changes, available nutrients and metabolic quotients are also discussed. This study demonstrates that changes in soils exposed to comparatively high temperatures (>500°C) have a particularly strong impact on microbial population.

A Classification of Sediment Types Based on Statistical Multivariate Techniques

In this paper the results of a characterization and classification of the mineralogical and chemical composition of some rural soils located close to five clay outcrops that supply the Castellon (spanish province) ceramic industry are presented. A total of 50 sediment samples were collected in accordance with statistical criteria and their chemical and mineralogical composition were determined. The classification of sediment types has been carried out using complementary statistical techniques: a hierarchical cluster analysis using Ward method and Euclidean distance to detect statistical significative groups (clusters) and a discriminant analysis of proximities to obtain probabilities. Univariate statistical descriptions have been computed for all variables. The statistical interpretation of the results suggests the existence of three main groups. Comparisons among them are computed.

Vectorial model to study the local breeze regimen and its relationship with SO2 and particulate matter concentrations in the urban area of Castellón, Spain

Abstract A study of SO2 and particulate matter pollution in the urban area of Castellon (Spain) and its relationship to meteorological parameters — wind direction, intensity and temperature, has been carried out. The topographic characteristics of the area under study influence local breezes. The study of the local breezes regime has been carried out using a vectorial model. The determination of meteorological parameters has been of great importance in examining the relationship with the concentration of SO2 and particulate matter. A decrease in particulate matter and SO2 pollution has been noted during the winter months as a result of stronger winds. An increase was noted when the wind direction was between 180° and 270° during the winter period and between 135° and 270° during the summer months, at all the stations where samples were taken. On the other hand, during the winter when temperatures rise, a decrease in the concentration of SO2 and particulate matter can be seen, whereas no such correlation can be seen for the summer months. The existence of a seasonal cycle was noted, more obviously in the case for particulate matter than for SO2 pollution. This could be due to the characteristic sea breezes which operate in this area.

Dust Air Pollution In A Mediterranean Industrial Area

The aim of this work is to characterize the mineral phases present in the atmosphere of Castellon, a city located on the Mediterrenean Coast of Spain. Samples of atmospheric particles were collected using a medium volume sampler, MCV-8D, in the centre of the city. A bracket of nitrate and cellulose filters (Millipore HAWP04700) with a pore diameter of 0.45 um was used. In order to determine major phases, the samples were analyzed by X-Ray diffraction using a Siemens D-5000 X-Ray powder diffractometer equiped with a thin film attachment. The samples were analyzed by SEM, using a Jeol scanning microscope with an energy dispersive X-Ray detector (EDX), using ZAP correction. The mineralogical study of the sample filters shows the presence of quartz, calcite, muscovite, kaolinite and dolomite as the principal phases. The microanalysis results confirm the mineral phases identified by X-Ray difractometry and enables us to identify the metals present in the particles.

Mineralogy and distribution of Cd, Ni, Cr, and Pb in biosolids-amended soils from Castellón Province (NE, Spain).

Heavy metals can be transferred from soils to other portions of the ecosystem, with effects at both the ecosystem level and on human health from transmission through the web chain. For several years, this environmental issue has concerned scientists. In this context, heavy metal concentrations were studied in agricultural soils devoted to vegetable crops in the province of Castellón (NE Spain), in areas of intensive agriculture. Currently, the use of biosolids to improve the nutrient contents of the soil is a common practice. Contamination of soils by potentially toxic elements (e.g., Cd, Ni, Cr, Pb) from amendments of biosolids is subject to strict controls in relationship to total permissible metal concentrations, soil properties, and intended use within the European Community. This study is aimed at determining the chemical partitioning of Cd, Ni, Cr, and Pb in agricultural soils repeatedly amended with sludge. The distribution of chemical forms of Cd, Ni, Cr, and Pb in five biosolids-amended soils was studied using a sequential extraction procedure that fractionated the metal into soluble-exchangeable, specifically sorbed-carbonate bound, oxidizable, reducible, and residual forms. The biosolids incorporation has modified the soil composition, leading to the increment of heavy metals. The residual, reducible, and carbonate-sorbed forms were dominant. The mineralogical association of the clay fraction was illite, kaolinite, and chlorite.

Environmental Pollution Management

Environmental pollution control is one of the most important goals in nowadays pollution risk assessment. In this sense modern and exact tools that allow scientists to evaluate, quantify and predict air pollution are of particular interest. In this paper we give a modern approach within this context analyzing data on air pollution coming from a GIS-based system and present the corresponding results.

Electrical conductivity measurements in sewage sludge pellets: innovative techniques for environmental management.

This paper presents research on the behaviour of electrical conductivity of sludge pellets resulting from the treatment of urban wastewater at the drying grounds of the El Trebal wastewater processing plant, located in the Mapocho river basin of the Metropolitana Region, Santiago, Chile. In the methodology used samples were taken that correspond to three horizons of the sewage sludge pile. The first horizon made up the upper portion of the pile (the surface), the second the central portion (mesophilous), and the third the lower one (thermophilous). Electrical conductivity measurements were taken in sewage sludge pellets under pressures on the order of 15-50 MPa with currents of 10(-15)A. Electrical conductivity measurements were also taken for different horizons, and innovative techniques and methodologies for sludge samples presented in the form of pellets are used for this purpose. Such pellets are easily reproduced with sufficient precision, and at the same time allow modifying other variables like mass, sample dimensions and compaction levels. The trends of the conductivity curves are similar for the sludge from the isolation surface horizon (H1) as well as for the mesophilous area horizon (H2). In the case of the thermophilous area horizon (H3), the electrical conductivity shows extremely high values when compared to horizons H1 and H2. This paper could be useful in establishing a general rule for taking electrical conductivity measurements in sewage sludge samples. Such a rule could bring accurate reproducible values, and be used for other types of dry wastes.

Non Crystalline Nature Spherical Particles As Possible Tracers Of Emissions Of The Ceramics Industry

Since the beginning of the century, the province of Castellon houses one of the biggest nucleus of ceramics production in Spain. During the last three decades this nucleus, mainly located around the villages of Onda and Alcora, has had an special process of industrial expansion to areas which, though their closeness, had never before experienced an excessive degree of industrial development. Nowadays, more than 93% of the Spanish ceramics industry is concentrated around the province of Castellon. Due to the high industrial concentration that the mentioned process has originated, the question arises: how far this industry and other kind of activities exert a negative effect on the quality of the environment necessary for the development of an agrarian sector devoted exclusively to the citric produces, and for the enjoyment of the villages close to the factories?. The development of the action plans guided to solve atmospheric pollution problems requires a precious knowledge of the nature and of the concentration of the different polluting agents that originate these problems. The concentration and the physical and chemical features of the polluting agents emitted through a certain productive circle would be clearly influenced by the raw material used in each stage of the process, by the conversion these raw materials are subjected to and by the installation working conditions. The emissions, most of them of particulate material, can constitute a real environmental problem in the tile sector or in the frits, glazes, and ceramic colours Transactions on Ecology and the Environment vol 29