Siliceous Raw Materials Research Articles

Characterization of XVIIIth century earthen mortars from Cremona (Northern Italy): Insights on a manufacturing tradition

Earthen mortars have been widely used in low and high status architectures of Cremona (Northern Italy) since Roman times until the XIXth century. The mineralogical, petrographic and geochemical study of XVIIIth century earthen mortars from Cremona allowed to have insights on the typology of silicate raw materials utilized for their production. The occurrence of CaO-rich levels with abundant neogenic phases and widespread dissolution textures suggests that small amounts of lime and other additives were blended with the silicate mixture. The results of this work help answer archeological questions about these poorly known masonry materials and provide insights for restoration purposes.

Flint economy in the Pyrenees: A general view of siliceous raw material sources and their use in the Pyrenean Gravettian

The aim of this article is to present a very general view of siliceous raw material sources in the central Pyrenees, with support from recent bibliographic references. To illustrate the use of these materials in the Upper Paleolithic, we chose the example of the Gravettian occupation of Gargas Cave (Hautes-Pyrénées, France). Finally, we describe a few economic characteristics of the Pyrenean region, which are distinct from the Perigordian context in several ways.

Influence of Silicate Structure on the Low Temperature Synthesis of Belite Cement from Different Siliceous Raw Materials

This paper studies the low temperature synthesis of β-C2S from mixture of lime, BaCl2 and siliceous raw material (white sand, metakaolin and dealuminated kaolin) with the ratio (Ca + Ba)/Si = 2. The Mixtures were hydrothermally treated in stainless steel capsule at 180°C for 5 hours and calcined at 750°C for 3 hours. Raw materials, hydrothermally treated and calcined mixtures were analyzed by FTIR, XRD, TGA/DTA and SEM techniques. The reactivity siliceous raw materials towards lime under hydrothermal treatment increase in the following order: sand, metakaolin, dealuminated kaolin. Because sand composes of quartz crystals, metakaolin composes of amorphous metakaolin structure while dealuminated kaolin composes from enriched amorphous silicate. Calcium aluminate and aluminosilicate hydrate were observed in case of metakaolin which contains appreciable amount of Al2O3. Dicalcium silicate crystallizes into β-C2S in the temperature range 590°C - 760°C. Finally, β-C2S transforms to α’-C2S in the temperature range 790°C - 860°C. There is no sign for the formation of γ-C2S. This proves that Ba2+ ions stabilized β-C2S and retards its transformation to γ-C2S because Ba2+ions replace some of calcium atoms in the structure of β-C2S.

Evaluating the Effectiveness of Producing the Activated Mineral Powders from Technogenic Raw Materials for Asphalt Mixtures

The article describes the grinding efficiency of siliceous raw materials in various grinding units with respect to the alteration of their surface area and the concentration of active sites on the surface. The influence of mechanical activation of dispersed materials on the physical and mechanical characteristics of asphalt concrete has been evaluated. The proportional relationship between the number of active adsorption sites on the surface of milled mineral powders and the intensity of their interaction with bitumen, strength and water resistance of asphalt concrete has been determined, which allows to recommend this index as an integral characteristic evaluation of reactivity of materials to mechanical activation.

Thermal Desorption Experiment of Polycyclic Aromatic Hydrocarbons (PAHs) Contaminated Soil Used as Cement Raw Meal

Sample polluted soil surrounding Shougang as object, TG, thermal analysis of raw soil and cement raw meal experiments were made, the results show that: the polluted soil contains a variety of PAHs of organic pollutants, the total concentration of PAHs is about 156.39ppm. PAHs contaminated soil can be divided into three stages of weight loss at 850°C: water losing stages, organic matter decomposition stages and inorganic carbonate decomposition stages. With the increase in heating temperature, removal rate of total PAHs in raw soil is high. Using polluted soil as cement siliceous raw material, except naphthalene, acenaphthene, two hydrogen acenaphthene and anthracene, other organic compounds of PAHs have residues at 300°Cand small amounts of phenanthrene have residue at 600°C, means cement raw material has certain adsorption of PAHs pollutants. Therefore, when co processing PAHs polluted soil into the cement kiln, considering should be focused the content of pollutants in flue gas volatilization and C2 raw mill especially.

Un exemple de gestion des géo-ressources au Paléolithique supérieur en moyenne montagne : le Badegoulien de la grotte du Rond-du-Barry (Sinzelles, Polignac, Haute-Loire)

Rond-du-Barry cave is situated in the centre of the Cenozoïc sedimentary basin of Puy-en-Velay in a mountainous environment. It contains Middle Palaeolithic, Badegoulian, Magdalenian and more recent occupation levels. Lying between two major river corridors (the Loire to the west and the Allier to the east), this site provides a special opportunity for defining exploitation and management modalities linked to the territory occupied by the prehistoric humans who inhabited the cave and the role played by the landscape's structural elements in human behavior at the end of the Upper Pleistocene. Lithic raw material analysis of the archaeological assemblages allowed us to define the dispersal of raw materials used in the site. Such dispersal has for some time been considered to provide a reliable reflection of actual movements of human groups. Our study, based on a modified methodology incorporating the concept of a chaine évolutive for flint, focused on the lithic artifacts from Rond-du-Barry unit F2, which are attributed to the Badegoulian. The results of our study differ from those of previous studies in terms of the diversity of the raw material being used and the frequency of occurrence for each type. Our conclusion is that Badegoulian humans were not physically constrained by a familiar territory, but traveled and/or traded widely in their quest for suitable raw materials. The diversity in the lithic raw materials, gathered locally and semi-locally from different primary and secondary outcrops demonstrates this territorial range. Importation of siliceous raw material originating from the meridional edge of the Paris basin (Berry, Touraine) suggests a planned resource-use strategy for obtaining large pieces of flint, which are rare in the regional outcrops. However, unraveling the resource use strategies to this degree of intention lies beyond what can be revealed by the lithic material alone.

New data about Cenomanian and Turonian chert from Charente’s basin (France)

Prehistoric studies in lithic raw materials have experienced some methodological innovations that have resulted in research breakthroughs. The transfer of methods from Geology to Archaeology has led to the development of a new discipline, Petroarcheology, which has allowed to go beyond the study of chert as a raw material, providing archaeological responses from Petrography’s own methods.Why did we choose the Charente’s basin samples?The history of research goes back to early 2000, with works like the PCR led by Anne Delagnes “Paléolithique Moyen dans le bassin de la Charente” and the doctoral thesis of Seon-Jing Park (2007), in relation to the question of Neanderthal human mobility and potential mineral resources of that basin. These works led to the initiation of different geoarchaeological surveys in search of quality siliceous raw materials for the manufacture of stone tools, whose positive results led, in 2002, to the creation of the regional lithothèque of Charente (Angoulême, France).This lithothèque, located at the Museum of Fine Arts in Angoulême and with a collection of 183 samples of siliceous rocks - chert, jasper (Riba, 1997) and claystones (Riba, 1997)-, has become over the years an essential and very important tool for scholars interested in siliceous raw material availability and procurement in that region.Our study has combined petrologic and micropalaeontological (both macroscopic and microscopic) analysis of all samples recovered from two of the four geological stages of the Upper Cretaceous represented in the lithothèque - Cenomanian and Turonian.We’ve described some different kind of chert and we’ve made location maps with the aim, in the future, of compare and relate to archaeological studies on the origin of lithic industries recovered in the archaeological deposits of the area.

Investigation of the usage of centrifuging waste of mineral wool melt (CMWW), contaminated with phenol and formaldehyde, in manufacturing of ceramic products

Large amounts of centrifuging waste of mineral wool melt (CMWW) are created during the production of mineral wool. CMWW is technogenic aluminum silicate raw material, formed from the particles of undefibred melt (60–70%) and mineral wool fibers (30–40%). 0.3–0.6% of organic binder with phenol and formaldehyde in its composition exists in this material. Objective of the research is to investigate the possibility to use CMWW as an additive for the production of ceramic products, by neutralising phenol and formaldehyde existing in CMWW. Formation masses were prepared by incorporating 10%, 20% and 30% of CMWW additive and burned at various temperatures. It was identified that the amount of 10–30% of CMWW additive influences the following physical and mechanical properties of the ceramic body: lowers drying and firing shrinkage, density, increases compressive strength and water absorption. Investigations carried out show that CMWW waste can be used for the production of ceramic products of various purposes.

Vers une caractérisation du gisement magdalénien d’Isturitz (Pyrénées-Atlantiques) à travers sa production artistique

This paper presents the results of the microscopic analysis of over 150 engraved pieces of mobiliary art from the Middle Magdalenian layers of the Saint-Périer and Passemard collections from Isturitz Cave (Saint-Martin d'Arberoue, Pyrénées-Atlantiques) kept in the Museum of National Antiquities (Musée d’Archéologie Nationale, Saint-Germain-en-Laye). These bone and lithic items were analyzed focusing on the engravers’ gestures, through the identification of technical indices. In order to do so, several experimental pieces were replicated and subsequently studied using both scanning electron microscope and binocular microscope. This has allowed us to identify various indices indicating the direction of the lines, as well as their order of execution. In some cases, specific marks associated with the a lack of proficiency in the use of the tool could be recognized. These same indices have also been identified during the study of the archaeological material. This approach has allowed us to reconstruct the chaîne opératoire implemented for making and decorating these objects, as well as to identify some diagnostic criteria enabling to ascertain the engravers’ level of expertise to be ascertained. The chaîne opératoire employed in the execution of the engraved motifs shows a high level of homogeneity in both the order of engraving the different parts of the figures and the direction of the lines. In With regards to the degree of expertise, the unskillful unskilled engravers are recognized recognizable by the accidents related to a lack of control of the tool when performing certain movements, such as curved lines, or their difficulty to in returning to a groove in order to deepen it. These artisans also drew clumsily and their motifs lack proportionality. By contrast, skillful engravers made the decorations without any kind of errors when tracing the lines, The objects made by theise engravers show certainbear witness to control of their control of movements, and also are sometimes example ofattest to artistic or technical innovation. The apprenticeship of the engravers during the Middle Magdalenian period can thus be addressed through this case study. Some objects seem to be the product of either skillful or unskillful unskilled engravers and craftspeople featuring an intermediate degree of apprenticeship are also involved. The artistic ensemble from Isturitz is particularly remarkable, not only for its abundance and diversity, but also because of a number of technical and formal innovations. We can consider the studied assemblage as a ‘ serial production’, i. e. the execution of works representing analogous themes on the same mattermaterial, and deploying similar techniques and formal conventions. Works by the same author have also been identified. In addition, it is essentially a production was essentially created by experienced artists. All the data provided by this study of the portable art from Isturitz allow us to speculate on the function of the site during the Middle Magdalenian, and to specify the characteristics of the its occupation. The nature of the relationships that Isturitz maintained with neighbouring local sites can therefore thus be better understood. The location of the Isturitz cave at the crossroads between the three most populated areas in the Middle Magdalenian (the Cantabrian region, the Pyrenees and the Aquitaine region), the proximity of siliceous raw material sources (Flysch and Chalosse), and the abundance and diversity of the archaeological record explain why, throughout the history of research, the site has been considered a place of aggregation used for periodic gatherings. The insights gained from the technical analysis of the portable art help testing modify this proposal hypothesis. Therefore, the paper advocates that Isturitz was a long-term intermittent habitat settlement, where the production of portable art during the Middle Magdalenian would have played a paramount role. Indeed, the homogeneity of the chaînes opératoires implemented to achieve the createion of artistic creations artefacts shows that we are not dealing with a set of objects brought to the site by artists from different groups and mastering different procedures and traditions. Instead, this consistency is a reflection of a coherent process, conducted mainly by highly experienced artists, sharing the same know-how.

Los sistemas de producción lítica en el Paleolítico Superior Final: El caso del nivel Asup del Molí del Salt (Vimbodí i Poblet, Tarragona)

In this paper we present the results of core analysis of Asup level from Moli del Salt site (Vimbodi i Poblet, Tarragona/Spain), dated to ca. 11 ka 14C BP (c. 12700-13000 years cal BP). This analysis was carried out from the methodological proposals raised by various authors as Guilbaud (1995) and Vaquero (1997). With this study, we try to define the operative field to better understand the variability of knapping strategies and the possible continuity relations among them used by the populations who occupied the site during the Final Upper Palaeolithic. This technological variability has been corroborated. In general, the cores present facial hierarchy and the extractions are long and narrow. Thus, there is a significant presence of blade knapping. In addition, we have differentiated six types of siliceous raw materials.

A Comparative Study on Production of Autoclaved Aerated Concrete by Coal Gangue Fly Ash

In this paper, compared with common fly ash, the low-silicon coal gangue fly ash is used to produce fly ash autoclaved aerated concrete. The influences of water binder ratio, coal gangue fly ash content, calcareous content and conditioning agents on the compressive strength of the autoclaved aerated concrete are investigated. The results indicate the coal gangue fly ash has different properties from the common fly ash such as its granule appearance and the activity as AAC siliceous raw material. It is noting that the coal gangue fly ash can also be used to prepare AAC blocks by optimizing the raw material formulation and procedure and its B05 product can reach the China top industrial standard.

Kinetics of Leaching Silicon from the Acid Leaching Residue of Pyrolusite

The content of SiO2 was more than 60% in the residue of pyrolusite detached manganese by reduction roasted and acid leached, and it was a better siliceous raw material because of less other impurities. Through leaching silicon process in the residue of pyrolusite with alkali at atmospheric pressure, leaching kinetics of silica in the sodium hydroxide solution was researched. The effects of the leaching temperature and the concentration of sodium hydroxide solution on the leaching behavior of silica from acid-leached pyrolusite slag were examinted. It was found that the extracting rate of silica is significantly influenced by the temperature, and the concentration of NaOH solution. The experimental datas were well interpreted with a shrinking core model under chemical control. On the basis of the Arrhenius expression the apparent activation energy of 77.69 kJ/mol and a reaction order of 0.34 for the extraction of silica was evaluated.

Towards a Better Understanding of the Chemical Reactions Between Iron Carbide and Silicon Carbide

<p>This article contains the research results of the equilibrium interaction of iron carbide (Fe<sub>3</sub>C) with silicon carbide (SiC) in a temperature interval of 700-2000 K with the formation of iron silicides (Fe<sub>3</sub>Si, Fe<sub>5</sub>Si<sub>3</sub>, FeSi, FeSi<sub>2</sub>), by using the program of the Finnish metallurgical company Outokumpy HSC Chemistryj-5.1 for Windows with regard to the electrothermal production of ferrosilicium from siliceous and carboncontaining raw materials. On the basis of the received regression equations connecting the Gibbs energy change with the temperature and the silicon content in a ferroalloy, the response surfaces (change of the Gibbs free energy - ∆G<sub>T</sub><sup>0</sup>) and their horizontal sections for three groups of ferroalloys were constructed with the program Mathcad. The silicon content in the first group of alloys is 14.3-23%, in the second group of alloys – 23-33.3% and in the third group of alloys – 33.3-42.8%. It was established, that the reactions between Fe<sub>3</sub>C and SiC with the formation of iron silicides in the range of temperatures 700-2000 K are possible, and the probability of these reactions increases with increasing the mole ratio Fe<sub>3</sub>C/SiC from 0.166 to 1.0. As a result of the reactions the low-silicon ferrosilicium can be obtained, answering to a grade FS20 with Si content from 19 to 27 % and consisting of a mixture of Fe<sub>3</sub>Si and Fe<sub>5</sub>Si<sub>3</sub>, and also the ferrosilicium corresponding to a grade FS25 with a Si content from 23 to 29% and consisting of a mixture of Fe<sub>5</sub>Si<sub>3</sub> and FeSi. It was found, that at the technological temperature of 1900-2000 K the maximum Si content in the received ferrosilicium can’t be more than 37.7 - 38.8%. Production of the medium-silicon and the high-silicon ferrosilicium answering to grades FS45- FS90 from the Fe<sub>3</sub>C-SiC mixture is impossible from a thermodynamic point of view. The received information extends our knowledge about the iron silicides formation during the electrothermal production of ferrosilicium with a silicon content in the alloy from 19 to 90%.</p>

From the Adour valley to the Gelise valley (western part of the Gers department): an important occurrence of siliceous raw material of Senonian origin.

This study refers the western part of the “Gers department” which covers the Adour valley, its tributaries (Izaute, Midour and Douze) and the Gelise valley. A geological study was carried out from 2010 to 2012. It allowed us to collect 290 alluvial siliceous pebbles from the Plio-Pleistocene sediments. At the same time, 132 flint artefacts from prehistoric sources in the Gers (Upper Palaeolithic) were collected. Petrographic, sedimentological and palaeontological studies were carried out. They allowed us to distinguish 19 lithological types:- 1 related to the Cenozoic formation;- 2 associated with Flysch deposits from the Pyrenean orogenic belt;- 10 attributed to the Senonian age (from the Coniacian to the Campanian);- 6 imputed to the Upper Maastrichtian with Lepidorbitoides.Then these types were brought together into six groups that show their stratigraphic positions and their palaeogeographic environments at different time periods.- 0.2 % of the alluvial pebbles were related to the Pyrenean Flysch;- 45 % were of Upper Maastrichtian age (Lepidorbitoides);- 54 % were of Senonian age (Coniacian to Middle Maastrichtian).The artefacts collected in the same region show a very similar proportion of siliceous pebbles (49 % of Maastrichtian with Lepidorbitoides).The result of this study is that, up to now, the western part of the Lannemezan Plateau includes alluvial areas of Plio-Pleistocene age, containing a large amount of flint pebbles of Upper Cretaceous age (Senonian and Maastrichtian). The gathering of this siliceous raw material by Palaeolithic communities is obvious. The identification of a new lithic raw material located in the southern Aquitaine Basin will have to be taken into account, while former interpretations probably have to be amended.

Multivariate Statistical Analysis of Phyllite Samples Based on Chemical (XRF) and Mineralogical Data by XRD

It is presented the results obtained of a multivariate statistical analysis concerning the chemical and phase composition, as a characterization purpose, carried out with 52 rock phyllite samples selected from the provinces of Almeria and Granada (SE Spain). Chemical analysis was performed by X-ray fluorescence (XRF). Crystalline phase analysis was performed by X-ray powder diffraction (XRD) and the mineralogical composition was then deduced. Quantification of weight loss (100? and 1000?C) was carried out by thermal analysis. The aims of this investigation were to analyze and compare the chemical and mineralogical composition of all these samples and to find similarities and differences between them to allow a classification. Several correlations between results of the characterization techniques have been also investigated. All the data have been processed using the multivariate statistical analysis method. The XRF macro-elements (10) and microelements (39) data generate one macrogroup with two new subgroups (1 and 2), and an isolated sample. In subgroup 1 of macroelements, a positive correlation was found between XRF results and geographic location characterized by lower MgO content, which is associated to its geological origins. When multivariate statistical analysis is applied to results obtained by XRD, two groups appear: the first one with a sample with zero percentage of iron oxide and the second one with the rest of the samples, which is classified in two groups. A correlation is observed between the alkaline content (XRF) and illite (XRD), CaO and MgO with dolomite and indirectly between the weight loss after heating at 1000?C and the contents of phase minerals that lose structural water (illite + chlorite) or carbon dioxide (dolomite). The present investigation has interest and implications for geochemistry and analytical chemistry concerning earth rocks and silicate raw materials.

Jazidas de rochas silicosas na área do Parque Nacional Serra da Capivara (Piauí, Brasil): primeiros dados geoarqueológicos

Nos artefatos líticos do Nordeste do Brasil são identificados diferentes tipos de matéria-prima silicosa, o que torna fundamental a caracterização petrográfica dessas rochas. As pesquisas desenvolvidas no abrigo da Pedra Furada levantaram questões acerca da economia da matéria-prima no Sudeste do Piauí, nos períodos do Pleistoceno e Holoceno. Porém, nenhum estudo geoarqueológico e petrográfico havia sido feito sobre os possíveis afloramentos das rochas trabalhadas na pré-história. Portanto, o objetivo desse trabalho é expor os métodos e os resultados preliminares do estudo das fontes de matérias-primas silicosas presentes nos afloramentos rochosos e nos depósitos sedimentares distribuídos na área do Parque Nacional Serra da Capivara (PARNA) e de seu entorno. Busca-se também relacionar as amostras coletadas ao instrumentário lítico de alguns sítios arqueológicos importantes para a região.

Assessment of the rice husk lean-combustion in a bubbling fluidized bed for the production of amorphous silica-rich ash

Rice husk lean-combustion in a bubbling and atmospheric fluidized bed reactor (FBR) of 0.3 m diameter with expansion to 0.4 m in the freeboard zone and 3 m height was investigated. Experiment design – response surface methodology (RSM) – is used to evaluate both excess air and normal fluidizing velocity influence (independent and controllable variables), in the combustion efficiency (carbon transformation), bed and freeboard temperature and silica content in the ashes. Hot gases emissions (CO 2, CO and NO x ), crystallographic structure and morphology of the ash are also shown. A cold fluidization study is also presented. The values implemented in the equipment operation, excess air in the range of 40–125% and normal fluidization velocities (0.13–0.15 Nm/s) show that the values near the lower limit, encourage bed temperatures around 750 °C with higher carbon transformation efficiencies around 98%. However, this condition deteriorated the amorphous potential of silica present in the ash. An opposite behavior was evidenced at the upper limit of the excess air. This thermochemical process in this type of reactor shows the technical feasibility to valorize RH producing hot gases and an amorphous siliceous raw material.

Reuse of water purification sludge as raw material in cement production

Abstract The feasibility of partial replacement of siliceous raw material for cement production with water purification sludge (WPS) was investigated by X-ray diffraction, free-lime analysis, compressive strength testing and toxicity characteristics leaching procedure (TCLP). It is found that WPS has no negative effects on the consumption of free lime and the formation of clinker minerals. The samples with WPS from 4 to 10 wt.% have higher 3 days and 7 days strengths than the control. After 28 days, however, only WPS replacements

Ultra Fine Layered Silicate Synthesis from Synthetic Silicate Raw Material

This paper reports the results of experiments on ultra fine layered silicates Na-fluorotaeniolite and Na-fluorotetrasilicic mica synthesis in the melts prepared from reaction blends based on synthetic silicate raw material, namely synthetic magnesium silicate dihydrate (MSDH, MgO·SiO2·2H2O). The MSDH–Na2SiF6–LiF, MSDH–Na2SiF6–MgF2 and MSDH–Na2SiF6–NaF blends, whose compositions are close to the stoichiometry of the Na-fluorotaeniolite (NaMg2Li[Si4O10]F2) and Na-fluorotetrasilicic mica (NaMg2.5[Si4O10]F2) were studied in the temperature range 1080–1225°C. Magnesium silicate dihydrate, the phase composition of synthesis products and layered silicates (Na-fluorotaeniolite and Na-fluorotetrasilicic mica) were examined using the crystal optical, X-ray diffraction at room and high temperatures, differential thermal and chemical analyses. It has been shown that studied blends possessed a high reactivity, owing to which the layered silicates were synthesized at lower temperatures (∼180–300°C) and the duration of the synthesis was shortened severalfold. The maximal yield of the Na-fluorotetrasilicic mica was observed in the reaction blend with the Na2SiF6 and NaF as halogen-containing compounds. The specific effects of MSDH on the physicochemical processes proceeded during heat treatment of the reaction blends were described.

THE PROSPECTS OF CREATION OF A MODIFIED INSULATING INORGANIC MATERIAL BASED ON SILICA AND ALUMINA MATERIAL

In the article the analysis of use of heat insulation materials inUkraineis given. The advantages of creation of heat insulation inorganic material on the basis of aluminum silicate raw material compared to the heat insulation materials utilized today are shown.