Platy Particles Research Articles

NiFe Layered Double Hydroxides with Controlled Composition and Morphology for the Efficient Removal of Cr(VI) from Water.

A layered double hydroxide (LDH) composed of Ni2+ and Fe3+ with a Fe3+/(Ni2+ + Fe3+) ratio of 0.05, which is not commonly available, was successfully prepared by coprecipitation from an aqueous solution of glycerol containing nickel nitrate and iron nitrate. Precipitation using NaOH as a precipitating agent at room temperature or 120 °C under hydrothermal conditions gave products with micrometer-sized aggregates of nanometer-sized unshaped particles, while that using urea yielded LDHs with a foam-like porous architecture composed of platy particles with a size of 100-300 nm. The products were examined to remove Cr(VI) from an acidic (pH = 3) aqueous solution of K2Cr2O7 by adsorption and photocatalytic reduction. The foam-like porous NiFe-LDH exhibited the highest adsorbed amount (122 mg g-1) and rate (0.017 g mg-1 min-1) in the dark and the highest rate (0.012 min-1) of photocatalytic Cr(VI) reduction among the NiFe-LDHs prepared in the present study, which can be explained as a positive effect of the foam-like porous architecture. These performances were superior to those of other reported LDHs, showing the importance of the composition and the particle morphology to boost the removal of Cr(VI).

Revisiting DLVO theory to inform particle-scale modelling of clays

Particle-scale modelling of clays requires defining an energy-separation function for a pair of platy particles. The Derjaguin, Landau, Verwey and Overbeek (DLVO) theory provides a convenient framework for developing such a function as it embeds the combined effect of pore-fluid temperature, dielectric permittivity, and electrolyte concentration. Therefore, it can underpin the modelling of clay mechanical behaviour associated with thermal and environmental loading. The DLVO theory assumes particle interactions to be controlled by the van der Waals forces and the Coulombic forces via the Electrical Double-Layer (EDL). This paper first explores the 1D EDL interactions via the thermodynamics-based Grand Potential for the case of parallel sheets (with infinitesimal and infinite thickness). For infinitesimal thickness sheets, it is shown that i) the approximate analytical solutions of the Poisson-Boltzmann equation provide a qualitatively robust representation of EDL interactions, ii) the EDL interaction is qualitatively similar regardless of whether the interaction is modelled assuming constant surface charge or surface potential thus eliminating the uncertainty about the most appropriate electrical boundary condition to model EDL interactions; iii) the mechanical pressure required to ‘aggregate’ two sheets interacting via the EDL is finite and not infinite as often assumed in the literature (i.e. van der Waals forces do not need to be invoked to generate the energy barrier that triggers face-to-face aggregation but it remains fundamental for the quantitative definition of the potential energy barrier responsible for particle aggregation). Finally, the paper compares the 1D solutions for infinitely extended particles with the numerical solutions derived for face-to-face finite cuboidal particles with different aspect ratios to investigate the 1D analytical solutions that can conveniently be used as a benchmark in particle-scale modelling.

Static liquefaction in the context of steady state/critical state and its application in the stability of tailings dams

Mining operations produce large quantities of tailings that must be handled and stored safely in a technical framework that reconciles economic restrictions and environmental sustainability. Unfortunately, the history of tailings deposits is marked by episodes of catastrophic failures, which is confirmed by the recent tailings dam collapses that occurred in Canada (Mount Polley), Australia (Cadia) and Brazil (Samarco and Brumadinio). Due to this alarming empirical evidence left by the mining industry worldwide, there is international concern and a demand to build these deposits safely from every point of view. In this scenario, the main geotechnical parameter that requires significant attention is the undrained residual shear strength, which is crucial to ensure the physical stability of a tailings dam. The critical state soil mechanic (CSSM) and/or the steady state of deformation provide the conceptual framework for evaluating this strength mobilized by particulate materials. However, despite the fact that these concepts are long established, some important aspects of soil behavior have not been clearly incorporated, which can seriously affect the estimation of the residual undrained shear strength. In this paper the effects of strain rate and reorientation of platy particles in fine-grained soils, the existence of a quasi-steady state (condition of minimum undrained strength) in sandy soils and the limitations of the state parameter are analyzed and discussed. In this context, the main goals are to minimize misjudgments in the estimation of the undrained strength and to introduce an alternative tool, the flow index, If, to evaluate the susceptibility of the occurrence of flow failure in tailings dams.

Structure refinement and magnetic properties of synthetic Co[formula omitted]Ge[formula omitted]O[formula omitted](OH)[formula omitted] phyllogermanate

Co3Ge2O5(OH)4 relates to a specific group of 1:1 layered compounds with an ability to form either platy or tubular particles depending on chemical composition. Despite successful synthesis and perspective application, there is a lack of information on its crystal structure and magnetic properties, granted by Co ions. Co3Ge2O5(OH)4 phyllogermanate nanoparticles have been obtained using a hydrothermal method and characterised using powder X-ray diffraction and magnetisation measurements. Triclinic symmetry with a 1:P1 space group has been established. The unit cell contains three layers perpendicular to the c crystallographic direction, with 7.6 Å spacing and −b/3 shift of the middle layer. At a low magnetic field of 100 Oe the compound undergoes a magnetic transition at TN=5.2 K. The field of 9 T is not sufficient to take the sample to a magnetically saturated state with an asymptotic magnetic moment of 2.43 μB/Co2+. The estimations of the intralayer and interlayer exchange constants give values of J1/kB=2.75 K and J2/kB=0.25 K, respectively.

Deposition of layered double hydroxide on non‐pretreated carbon cloth using lactate salts as raw materials

AbstractThis study presented the successful deposition of layered double hydroxide (LDH) onto non‐pretreated carbon cloth (CC) using lactate salts as raw materials. Specifically, under the hydrothermal condition using urea hydrolysis and lactate salts as the source of Mg and Al, MgAl‐LDH was deposited onto the CC surface, which is typically treated with organic solvents and acids to enhance its hydrophilicity prior to LDH deposition. X‐ray diffraction patterns, field‐emission electron microscope images, and elemental analyses revealed the deposition and coating of hexagonal platy particles of a carbonate‐type MgAl‐LDH with pseudo hexagonal phase and Mg/Al molar ratio of 1 onto CC. This LDH coating was not achieved when using chlorides and nitrates, which commonly used Mg and Al sources. These results demonstrated the effectiveness of the proposed method for facile LDH deposition on hydrophobic surfaces.

A three-dimensional image reflecting the dispersion state of ceramic platelets in solvent: Observation of montmorillonite dispersed in silica gel by synchrotron X-ray multiscale tomography

Visualizing montmorillonite (MMT) platy particles dispersed in silica gel was firstly demonstrated by synchrotron X-ray multiscale tomography. The silica sol-gel reaction proceeded with the preservation of MMT dispersibility in water, MeOH, and DMF mixture. The 3D image reconstructed using high-resolution X-ray computed (CT) images (i.e., nano-CT) displayed platy particles in the range of 0.5—2.5 μm, which matched that observed in the field-emission microscope image of powder MMT. In addition, some platy particles are assembled by contacting their edge and layered surfaces, suggesting the presence of a house-of-cards structure. Given a decrease in the distance by 30% between platy particles roughly estimated using a decrease in volume by 65% before and after silica gelation, a dispersion state formed by micrometer-sized platy particles did not essentially differ after silica gelation. Therefore, these results indicated that the 3D image of MMT platy particles in silica gel reflected the dispersion state of MMT particles in the solvent.

Particle shape effects on granular column collapse using superquadric DEM

This paper presents a systematic study of particle shape effects on granular collapse using superquadric Discrete Element Method. Superquadrics allow non-spherical shapes to be accurately described by varying shape parameters, namely blockiness and particle aspect ratio. Simulations of low and high column collapse with various particle shapes from spheres to elongated/platy cubes are conducted. We found that the collapse of particles with higher blockiness results in shorter runout distance, increased retained height and more particles stacking along boundary walls. Particle blockiness also has clear influence on critical column aspect ratio and scaling law constants. Elongated and platy particles cause uneven deposit surfaces; however, the effects on runout distance, retained height and scaling law constants are relatively different between these two shapes. Particle sphericity, on the other hand, shows trivial effects on granular collapse. These findings significantly complement the understanding of the exclusive effects of particle shapes on granular collapse response.

Preparation and characterization of titania supported on layered double hydroxide precipitated on glass fiber cloth

Support of titania nanoparticles on platy particles of a layered double hydroxide (LDH) on glass fiber cloth (GFC) is demonstrated. MgAl-LDH was deposited onto the GFC surface via homogenous precipitation using urea hydrolysis in the presence of GFC. X-ray diffraction (XRD) patterns, field-emission scanning electron microscopy (FE-SEM) images, and elemental analyses revealed that MgAl-LDH platy particles were deposited and vertically aligned on the GFC surfaces, forming MgAl-LDH-coated GFC. The resultant specimen was soaked in a water dispersion of P25 standard, a well-known titania photocatalyst, for 5 min at room temperature and then extensively washed with an excess of water. The presence of P25 nanoparticles on the MgAl-LDH platy particles on GFC surfaces was evidenced by FE-SEM imaging, elemental analyses, and MB decomposition experiments in which an MB solution showed a greater decrease in concentration under 365 nm irradiation in the presence of the supported P25 than in the presence of MgAl-LDH-coated GFC and GFC subjected to the P25 deposition procedure without MgAl-LDH deposition. In addition, FE-SEM images and elemental analysis of the supported P25 specimen showed only small differences before and after the MB experiment. Therefore, the results mentioned above show the facile support of P25 on MgAl-LDH supported on a GFC surface.

Concentration dependence of yield stress of bentonite suspension and corresponding particle interactions

The prediction of the concentration dependence of the yield stress of bentonite suspension is important for both practical use and fundamental study. Whilst a great amount of research work has been undertaken concerning the theoretical prediction based on the Face-Face repulsive interactions alone, the effect of inclination angle α and separation distance D between clay particles has seemingly received little attention in the research literature. This article presents the prediction model of yield stress developed using the strength of interparticle interactions between two non-parallel platy particles of finite dimensions, aimed at providing insights into the evolution of interparticle interaction with increasing the mass fraction. The repulsive force between the particles for a range of values of geometrical parameters computed using the Gouy-Chapman theory of electrical double layer, along with the calculation presented on van der Waals force, provide a more quantitative means of evaluating the interparticle force in bentonite suspension. It was found that as α and D between particles increase, the magnitude of interparticle force including repulsive and attractive force decreases quickly. The ultimate comprehensive investigation indicated that as the mass fraction of bentonite suspension increases, interparticle interaction propagates from attractive interaction to repulsive attraction, and finally shifts to attractive interaction. In this process, inter-particle separation distance decreases, accompanied by a transition process from a larger inclination angle to a nearly parallel orientation between the particles. The prediction model of yield stress considering the influence of concentration variation on α and D yields a good prediction of experimental data. The results of the present study should help interpret test results in cases where it may not be entirely possible to maintain a parallel particle orientation.

Effect of Vanadium Oxide on the Crystallization of CaO-Al2O3-SiO2 Glass.

This study investigated the effect of vanadium oxide on the crystallization of CaO-Al2O3-SiO2 (CAS) glass. Specifically, this study subjected CAS glass-ceramics (GCs) with precipitated hexagonal platy particles of metastable CaAl2Si2O8 (CAS GC-H), a layered crystal, that was prepared using metallic molybdenum (Mo) particles as nucleation agents. When the parent glass of CAS GC-H was crystallized with the addition of vanadium oxide in the 0.052-0.21 wt % range, the obtained platy particles of metastable CaAl2Si2O8 displayed an increase in the aspect ratio from 20 to 15 compared with conventional CAS GC-Hs. In addition, no crystallization occurred in the CAS glass with vanadium oxide in the 0.052-0.21 wt % range in the absence of metallic Mo particles. Meanwhile, a CAS glass containing 1.0 wt % vanadium oxide without the addition of metallic Mo particles showed the precipitation of metastable CaAl2Si2O8. Therefore, these results indicated that the aspect ratio of layered crystals in glass was controlled by the addition of a relatively small content of vanadium oxide, and a new nucleation agent for the precipitation of metastable CaAl2Si2O8 in CAS glass using a relatively high content of vanadium oxide was developed.

Insight on bulk shear strength parameters of clay using discrete element approach incorporating physics-based interparticle force model

This paper aims to provide insight on factors affecting the bulk shear strength parameters of clay, i.e., the cohesion and internal friction as well as the effects of memory of preconsolidation pressure. A unique Discrete Element Method (DEM) model is built on platy particles with customized particle interaction force model. The particle interaction force model considers non-contact forces (such as the long-range electrostatic repulsion, short-range van der Waals attraction) as well as the direct contact force. The long-range electrostatic forces are calibrated by measurement with Atomic Force Microscope (AFM). Parameters for direct particle contacts of the regular DEM contact model, such as the contact stiffness and the friction coefficient, are calibrated by use of experimental consolidation and direct shear testing data. Computational simulations are conducted on digital clay specimen subjected to virtual direct shear tests. The predicted experimental responses of the digital specimens are consistent with typically observed in experiments including the shear stress-shear strain relationship, volumetric contraction and dilation, shear band formation, etc. From the stress–strain curves, the soil strength parameters are obtained with common experimental criteria. The DEM simulation results show that higher preconsolidation pressure drives more particles to overcome non-contact force into direct contacts and consequently bonding by van der Waals force. Consequently, the bulk cohesion of clay increases with increasing preconsolidation pressure. The results show that bulk cohesion strength is mainly attributed to the attractive interparticle force as well as the interlocking of platy particle, while the bulk internal friction angle is affected by the particle friction coefficient and particle fabric. Overall, the simulation results indicate the experimentally observed macroscopic shear strength parameters c and φ are linked to the microscope characteristics of soil particles and their mutual interactions. The results offer insight on the microscopic properties of particles on the bulk macroscopic strength behaviors. Besides, this work demonstrates a new strategy for simulation-based prediction of bulk soil strength parameters, by incorporating microscale characterization of the interparticle interactions and particle fabric into the particle-based DEM model.

Effect of starting materials of nucleation agents on crystallization of CaO–Al2O3–SiO2 glass

AbstractThe effect of the starting materials of the nucleation agents for glass–ceramics (GCs) was explored. The number of hexagonal platy particles of metastable‐CaAl2Si2O8 in CaO–Al2O3–SiO2 (CAS) GCs was increased by changing the sizes of molybdenum oxide (MoO3) and carbon particles used as starting materials of the nucleation agents. X‐ray diffraction patterns indicated that all of GC specimens display reflections attributed to metastable‐CaAl2Si2O8 solely. In addition, scanning electron microscopy (SEM) revealed that, compared with the CAS GC with precipitated hexagonal platy particles of metastable‐CaAl2Si2O8 (CAS GC‐H) prepared using MoO3 particles with a Brunauer–Emmett–Teller (BET) surface area of 3.5 m2/g and 10–50 μm carbon particles, CAS GC‐Hs prepared using MoO3 particles with a BET surface area of 1.2 m2/g or carbon fibers 10–50 μm in length and ∼5 μm in diameter resulted in approximately a twofold increase in the number of platy particles of metastable‐CaAl2Si2O8 and a decrease in the average particle size from 13 to 11 μm. The microstructures of the CAS GC‐Hs are closer looks. In addition, no major differences in volume fractions estimated using the binarized SEM images are observed between those GC specimens. These results indicated that the starting materials of nucleation agents affect the crystallization of CAS GCs.

Microstructural Control of CaO-Al2O3-SiO2 Glass Ceramics by Oxidation and Mixing with Nucleation Agents.

Microstructural control of CaO–Al2O3–SiO2 (CAS) glass ceramics (GCs) was achieved by oxidation and mixing with nucleation agents. CAS GCs were precipitated with hexagonal platy particles of metastable CaAl2Si2O8 layered crystals (CAS GC-H), which are typically prepared under a reductive atmosphere that forms metallic Mo or W particles as nucleation agents. The average particle size of crystals decreased significantly from 50 to 11 μm when the CAS GC-H containing metallic W particles was prepared under an oxidative atmosphere. Compared to this CAS-GC-H, the crystal particle size increased from 8–20 to 10–30 μm when the CAS GC-H was prepared by mixing glass cullet containing metallic Mo and that containing metallic W particles. These results indicate that one microstructure of CAS GC-H is controlled on the micrometer scale from a parent glass with one composition by varying the experimental conditions related to the glass melting state.

Viscoelasticity and shear resistance at the aggregate scale of structured and organic carbon-free Chernozems

Soil rheology characterises the flow behaviour of soils at the particle-particle to aggregate scale. Amplitude sweep tests (ASTs) are often the method of choice for parameterizing soil flow properties, such as the shear strain values at the end of the linear viscoelastic range (i.e., the deformation is mainly elastic) and at the yield point (i.e., elastic equals plastic deformation). Samples from seven soil profiles and five soil depths of Chernozems, collected in the Maidanetske study area, close to Uman City of Ukraine, were analysed to evaluate the effect of soil organic carbon (SOC) on the parameters related to soil microstructural stability derived from ASTs. Soil organic carbon was removed with H2O2 to determine the soil texture-dependent values of soil rheological properties, which were compared to the values determined for samples with intact water-stable aggregates. The shear resistance-related parameters increased for aggregated soil samples compared to SOC-free soil samples, indicating an increase in soil stability due to SOC. In contrast, the values of the overall viscoelasticity and the shear strain were reduced for aggregated soil samples, indicating decreased soil stability. Pedotransfer functions were applied to predict the shear strain-dependent loss and storage moduli and shear stress values as a function of SOC depletion. Coarse particles (630–2 000 μm) and volumetric water content improved the models. We conclude that increased SOC content, through the gluing and cementing effects of SOC and altered aggregate shapes compared to SOC-free soil materials, contributes to higher microstructural strength. However, the increased water content in the SOC-containing soil samples reversed soil strengthening effect. This was due to the fact that a more rapid increase in positive water pressure under shear stress weakened the samples and the spherical aggregates began to rotate more easily, thus loosing energy, when compared to platy particles of the SOC-free soil materials.

Simple and cost-effective mass production of nitrate type MgAl layered double hydroxide: Titration from concentrated solution

A mass production of nitrate type Mg/Al layered double hydroxide was examined by co-precipitation from solution by the titration of concentrated solution of metal salts with ammonium hydroxide under ambient atmosphere. The influence of the suspension pH and post precipitation aging on the products was studied. Over five grams of single-phase nitrate type Mg/Al layered double hydroxide was obtained from a hundred-milliliter suspension (initial concentration of metal salt solution of 1.6 M), which corresponded to 97% yield from the metal ion consumption. Well-defined platy particles of nitrate type Mg/Al layered double hydroxide nanoparticles were obtained by applying post precipitation aging at 80 °C under ambient atmosphere. The sample preparation has been carried out without any caution to remove carbonate contamination to obtain nitrate type Mg/Al layered double hydroxide.

Facile solvothermal synthesis of plate-like submicron NaNbO3 particles

Platy particles of NaNbO3 were successfully prepared by a solvothermal reaction using a methanol/ethanol mixed solvent, in contrast to the formation of cubic NaNbO3 particles from methanol alone.

Well-Defined Hexagonal Platy Particles of Brucite, Brucite/Silica Core Shell, and Hollow Silica Particle

Abstract Well-defined Mg(OH)2 (brucite) hexagonal platy particles with the lateral size of 80 nm were prepared by precipitation from an aqueous solution of magnesium chloride using a flow reactor with controlled pressure injection. The brucite particles were coated with a thin silica layer by hydrolysis and condensation of tetraethyl orthosilicate (TEOS) catalyzed by ammonium hydroxide to obtain Mg(OH)2@SiO2 core-shell nanoparticle. The heat treatment of the Mg(OH)2@SiO2 in air at 500 °C resulted in the transformation of brucite to periclase MgO. The Mg(OH)2 and MgO cores were removed from Mg(OH)2@SiO2 and MgO@SiO2 core-shell particles by etching with hydrochloric acid to obtain hollow silica particles with a lateral size range of 6 to 12 nm. Meanwhile, heat treatment of the Mg(OH)2@SiO2 at 1000 °C resulted in the transformation of brucite to periclase and forsterite.

PLATYMATCH – A particle-matching algorithm for the analysis of platy particle kinematics using X-ray Computed Tomography

Particle scale mechanisms influence the mechanical behaviour of geomaterials. A better understanding of soil micromechanics will help develop more accurate constitutive models and, by extension, safer and more economic geotechnical design. Sand-grained soils have been widely studied at the particle scale using X-ray Computed tomography and this has revealed important micromechanical behaviour of sands. Clays are least understood and studied at the particle scale. As technology rapidly progresses, to understand clay kinematics, a particle kinematic algorithm to match plate shaped (platy) particles will be required. Current algorithms developed for the matching of quartz and carbonate sand particles may not be suitable, since particle attributes that are strong discriminators of round particles may be less unique on platy particles, due to their extremely small c-axis and the reduced image resolution associated with their smaller size. This study presents, particle tracking of kaolin sample using mica markers and provides a platy soil particle matching algorithm for evaluating platy particle kinematics. After testing a range of alternative particle attributes, it was observed that a combination of particle major axis length, intermediate axis length, and perimeter was a good discriminant of the platy mica particles studied. On this basis, we developed PLATYMATCH, an optimised platy particle matching algorithm that considers a minimised combined normalised error of unique particle attributes within a defined search volume space. The algorithm was implemented such that particle attributes were compared in parallel, rather than sequentially, to avoid filtering out a potential particle match based on a single non-unique attribute. PLATYMATCH was then successfully validated using a compressed mica soil sample.

Illite and chlorite cementation of siliciclastic sandstones influenced by clay grain cutans

The distribution and amount of clay rim cements are different for Permian Rotliegend and Lower Triassic Bunter sandstones in the Southern Permian and German Triassic Basins, respectively. Both are similar fluvial-aeolian deposits in hot-arid endorheic basins. In both Permian and Triassic sandstones clay grain cutans can be present, but clay rim cement is often lacking or rare in Bunter sandstones. At first sight it would appear that the presence of cutans is thus not relevant for the development of clay cementation. However, at closer inspection, it appears that authigenic clay is indeed present in both cases. In Rotliegend sandstones, the authigenic clay mainly developed as rims around the clay grain cutans, which are often thin and well microlaminated with few intra-micropores and composed of platy particles. The clay crystals in the rim decrease the pore interconnectivity and lower permeability significantly. In Bunter sandstones, most of the authigenic clay developed within the cutans. These cutans are less well microlaminated, have ample micropores, and are composed of more equant-shaped particles. The latter looser structure facilitated clay authigenesis within the cutans and their micropores. This often led to exfoliation of the cutan laminae and expansion of the entire cutan. These expanded cutans also lower pore connectivity. The presence and thickness of clay rim cement on top of cutans and grains is thus not correlated with the thickness of the cutans but with the texture of the cutans. The latter determined where authigenic clays precipitated and the thickness of cutans is partly the result of clay authigenesis within the cutans. This demonstrates that the composition and the texture of sedimentary components constrained and controlled burial diagenesis.

Upper Paleolithic ceramic figurines and similarities to some late Pleistocene pigment and pottery materials and technologies of Eurasia

Three soft stone technologies that characterize the Upper Paleolithic period are fired ceramic figurines, pigments prepared from colored minerals that often consist of or include clay, and, lastly, pottery vessels. The earliest synthetic material of which we have a permanent artifactual record was made at 26,000 cal BP (Klima 1959b, 1963), marking the beginnings of chemical technology and pyrotechnology and is the concern of the first part of this paper. A review is presented of Upper Paleolithic ceramic figurines at the group of habitation sites in Moravia that includes Dolní Věstonice, Pavlov, Předmosti and Petřkovice. Dolní Věstonice, the only proven production site with the largest collection of ceramics, was the focus of the study because of the possibility of analyzing figurine fragments, kiln remains and raw materials that enabled reverse engineering of the technology. The size of the ceramic inventory and the presence of kilns argue for intentional production of ceramic objects and demonstrates that the relevant cultural practices over time involved repetition and both transmission and learning of a specific, patterned performance behavior of ceramic technology. The high fracture rate encountered and the resistance of the raw material to thermal shock, however, strongly suggest that what was important was not the final, durable product, but rather the process of making and firing and/or refiring of the objects, probably for ritual, ceremonial and political purposes. Similar additive fabrication methods and firing of local pluvial clay deposits was practiced at the site of Maina in Siberia at ca. 15,000 cal BP to make a singular ceramic figurine. At the southern end of the Urals is Kapovaya, a cave with images and a date similar to those at Lascaux and where a single small bowl that may be a fired ceramic was excavated.The second part discusses examples of ceramic processing technology without firing, if we understand ceramics as we define them today to include non-clay products made by processing of fine sub-10 μm, equiaxed or platy particles. Fine clay and pigment particles behave similarly when processed. Clays and pigments were processed at the cave site of Lascaux where excavation of the floor produced evidence of selected, collected and imported naturally occurring mineral and sediment blocks as well as fabricated chalk-like sticks referred to as “crayons.” These ground and fabricated blocks were used as manufacturing elements to apply red, yellow and black pigment to the cave walls at Lascaux. Stone ‘palettes’ were excavated from the floor with in-situ powders that indicate grinding and mixing of clays and pigments. This mixing also occurred on the tips of crayons.The third part is focused on a third ceramic performance technology that preserved physical health of community members: the making and using of pottery vessels for cooking and storage, and a description of some problems involved in reconstructing the processing technology.