scholarly journals Mineralogical characterization of clays used in the structural ceramic industry in west of S. Paulo State, Brazil

Cerâmica ◽  
2001 ◽  
Vol 47 (304) ◽  
pp. 204-207 ◽  
Author(s):  
S. R. Teixeira ◽  
S. A. de Souza ◽  
C. A. I. Moura
Keyword(s):  
Grain Size ◽  
Organic Matter ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Ceramic Industry ◽  
Raw Materials ◽  
Raw Material ◽  
Mineralogical Characterization ◽  
Paulo State ◽  
Ceramic Mass

Plasticity and the grain-size distribution of the raw material used to make structural bricks and roof tiles are very important to the production process. These two parameters and the mineral composition will define the quality and properties of the final product: color, mechanical resistance, water absorption, cracks, swell and shrink during drying and firing the ceramic pieces etc. In the Brazilian ceramic industry it is very common to mix together two or more different kinds of raw material to achieve the ceramic mass with the desired grain-size distribution. The objective of this work was to characterize the raw material collected at the floodplains of the Paraná and Paranapanema Rivers and the ceramic mass used by the ceramic industry in western São Paulo State, Brazil. Particle size distribution, organic matter and X-ray diffraction were used to study this material. The textural analysis indicates that the raw materials have the clay fraction ranging from 38.2% to 66.3%, the silt from 22.2% to 49.7% and the sand from 3.1% to 34.1%. The results indicate that all mixed raw materials have more clay in its composition than would be necessary. The organic matter ranges from 5 to 7%. All samples have kaolinite and many of them have smectites, HIV and mica. Gibbsite, iron and titanium oxides, and quartz are also identified. One of the samples (yellow) is rich in goethite.

Grain-size distribution of Italian raw materials for building clay products: a reappraisal of the Winkler diagram

Clay Minerals ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 435-442 ◽  
Author(s):  
M. Dondi ◽  
B. Fabbri ◽  
G. Guarini
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Raw Materials ◽  
New Classification ◽  
X Ray ◽  
Size Characterization ◽  
Good Behaviour ◽  
Hollow Bricks

AbstractThe grain size of raw materials influences their behaviour during the technological process and affects many properties of building clay products. Over the last few years, brickworks have been technologically updated and grain size requirements have been modified to ensure good behaviour during shaping and drying. Therefore, the reference schemes used to assess the suitability of clays, such as the classic Winkler diagram, should be updated.For this purpose, the grain-size distribution of 350 clays currently used in ~240 Italian plants was determined by X-ray monitoring of gravity sedimentation. Raw materials are basically represented by silty clays and clayey silts, while bodies present a narrower grain-size range. With reference to the Winkler diagram, most of the Italian bodies fall within the field of ‘thin-walled hollow bricks’, with no significant differentiation among the various product types.In order to improve the grain-size characterization of bodies, a new classification scheme for Italian raw materials is proposed, based on three ranges: >10 µm, 2-10 µm and <2 µm, respectively. It allows distinction of specific grain-size features of bodies for (a) facing bricks; (b) roofing tiles; and (c) lightweight blocks, paving bricks and hollow slabs.

Production of ceramic bodies from Tunisian Cretaceous clays

Clay Minerals ◽  
2012 ◽  
Vol 47 (1) ◽  
pp. 59-68 ◽  
Author(s):  
M. Hachani ◽  
W. Hajjaji ◽  
B. Moussi ◽  
M. Medhioub ◽  
F. Rocha ◽  
...  
Keyword(s):  
Grain Size ◽  
Physical Properties ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Late Cretaceous ◽  
Mineralogical Composition ◽  
International Standards ◽  
Raw Material ◽  
Ceramic Tiles ◽  
Firing Range

AbstractThe aim of this research was to assess the potential application of the Late Cretaceous levels as raw material for the production of ceramic tiles. Mineralogical, chemical and grain size distribution studies were carried out on four clays sampled at different sites in the Tunisian Central Atlas. Clays are mainly composed of phyllosilicates, usually illite and kaolinite. Quartz, feldspars and dolomite were also detected.Tiles were prepared by pressing clay bodies at 250 bar and then firing at different temperatures following industrial conditions as closely as possible. Thermal analysis showed the influence of mineralogical composition and grain size distribution on the material behaviour during firing. The physical properties of fired tiles were obtained from specific tests in accordance with international standards (ISO), i.e. the firing shrinkage, water absorption, apparent density and flexural strength. The development of physical properties indicates an optimal firing range between 1050–1150°C. Results demonstrate the potential of Late Cretaceous materials as raw materials for the production of ceramic tiles.

scholarly journals Characterization of mobilized sediments and organic matter in retrogressive thaw slumps on the Peel Plateau, NWT, Canada

2020 ◽  
Author(s):  
Lisa Bröder ◽  
Kirsi Keskitalo ◽  
Scott Zolkos ◽  
Sarah Shakil ◽  
Suzanne Tank ◽  
...  
Keyword(s):  
Grain Size ◽  
Organic Matter ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Active Layer ◽  
Organic Matter Content ◽  
Matter Content ◽  
Permafrost Soils ◽  
Extractable Organic Matter ◽  
Peel Plateau

&lt;p&gt;The Peel Plateau in northwestern Canada hosts some of the fastest growing &amp;#8220;mega slumps&amp;#8221;, retrogressive thaw slumps exceeding 2000 m&lt;sup&gt;2&lt;/sup&gt; in area. The region is located at the former margin of the Laurentide ice sheet and its landscape is dominated by ice-rich hummocky moraines. Rapid permafrost thaw resulting from enhanced warming and increases in summer precipitation has been identified as a major driver of sediment mobilization in the area, with some of the largest slumps relocating up to 10&lt;sup&gt;6&lt;/sup&gt; m&lt;sup&gt;3&lt;/sup&gt; of previously frozen sediments into fluvial networks. The biogeochemical transformation of this thawed substrate within fluvial networks may represent a source of CO&lt;sub&gt;2&lt;/sub&gt; to the atmosphere and have a large impact on downstream ecosystems, yet its fate is currently unclear. Concentrations of dissolved organic matter are lowered in slump-impacted streams, while the particle loads increase. Here, we aim to characterize the mobilized material and its sources by analyzing active layer, Holocene and Pleistocene permafrost, debris (recently thawed, still at the headwall) and slump outflow samples from four different slumps on the Peel Plateau. We use sediment properties (mineral surface area, grain size distribution), carbon isotopes (&lt;sup&gt;13&lt;/sup&gt;C, &lt;sup&gt;14&lt;/sup&gt;C) and molecular markers (solvent-extractable lipids, lignin phenols, cutin acids, non-extractable compound classes analyzed by pyrolysis-GCMS) in order to assess the composition and quality of the mobilized sediment and organic matter and thereby improve our understanding of their fate and downstream effects. Preliminary results show that organic matter content and radiocarbon age in debris and outflow from all four slumps are dominantly derived from Holocene and Pleistocene permafrost soils with a smaller influence of the organic-rich active layer. Degradation proxies based on extractable lipid and lignin biomarkers suggest Holocene and Pleistocene permafrost organic matter to be more matured than the fresh plant material found in the active layer, while debris and outflow samples show a mixed signal. For the non-extractable organic matter, aromatics and phenols make up the largest fraction of all samples. Lignin markers are almost exclusively found in the active layer samples, which also contain a larger proportion of polysaccharides, while N-containing compounds and alkanes make up the remaining 2-25 % with no obvious patterns. Active layer soils also have the highest median grain sizes, whereas Pleistocene permafrost soils consist of much finer mineral grains. Samples collected at the slump outflow are significantly more homogeneous (i.e., showing a narrower grain size distribution) than any of the other samples. We thus infer that both organic matter degradation and hydrodynamic sorting during transport play a role within these slump features; determining their relative magnitudes will be crucial to better assess potential feedbacks of these increasingly abundant &amp;#8220;mega slumps&amp;#8221; to changing climate.&lt;/p&gt;

Sign in / Sign up

Export Citation Format

Share Document