Magnesium Carbonate Powder Research Articles

Natural Rigid and Hard Plastic Fabricated from Elastomeric Degradation of Natural Rubber Composite with Ultra-High Magnesium Carbonate Content.

It is known that natural rubber is an elastomeric polymer; hence, the main uses are usually limited to soft applications. For the process to reverse the elastomeric effect of natural rubber to obtain rigid plastic from a natural material, an ultra-high amount of magnesium carbonate particles was added to the natural rubber to study the effect of magnesium carbonate in the reduction of elastomeric properties. High magnesium carbonate ratios of 80-180 phr were mixed in the natural rubber in the latex form to maximize the mixing capability since it was more difficult to achieve these mixture ratios with only two roll mill or extruder processes. The more magnesium carbonate powders in the composite, the higher torques were measured from the moving die rheometer (MDR) test. The powder was thoroughly mixed inside the composite, which was observed from energy-dispersive X-ray spectrometer (EDX) mapping; however, the matrix of composites was filled with porosity due to the CO2 formation when latex with magnesium carbonate was assimilated with acid during the vulcanization process. The strength of the composite dropped, and the elongations were shortened. On the other hand, the hardness of composites was drastically increased. The composite lost the elastomeric property, and the hard natural rubber composites were obtained.

Cold sintering of the Mg–C–O–H system

The cold sintering process reproduces the formation of sedimentary rocks in the Earth's crust by molding raw powder and a small amount of solvent at temperatures of about 300 °C or less under uniaxial pressure of several hundred megapascals. Generally, carbonates and hydroxides cannot be hardened by conventional sintering process due to thermal decomposition. In contrast, when this cold sintering process is selected, since the densification of the starting powder can be achieved by a dissolution-precipitation reaction with water as a solvent, carbonates and hydroxides can be hardened at temperatures below their decomposition temperatures. In the Mg–C–O–H system, magnesium hydroxide and a basic magnesium carbonate were selected as starting compounds, and the mechanism of their densification by a cold sintering process was investigated. The average compressive strength of the obtained magnesium hydroxide solidified products after cold sintering at 250 °C and 270 MPa for 60 min, and basic magnesium carbonate solidified products after cold sintering at 150 °C and 270 MPa for 60 min, were 121 MPa (84% relative density) and 275 MPa (88% relative density), respectively. The added water was found to play an important role in promoting a solution-precipitation process inside the magnesium hydroxide or basic magnesium carbonate powder compact, resulting in low-temperature sintering to form hardened bodies in the Mg–C–O–H system.

Syntheses of Nanostructured Magnesium Carbonate Powders with Mesoporous Structures from Carbon Dioxide

In this work, we present the results of two synthesis approaches for mesoporous magnesium carbonates, that result in mineralization of carbon dioxide, producing carbonate materials without the use of cosolvents, which makes them more environmentally friendly. In one of our synthesis methods, we found that we could obtain nonequilibrium crystal structures, with acicular crystals branching bidirectionally from a denser core. Both Raman spectroscopy and X-ray diffraction showed these crystals to be a mixture of sulfate and hydrated carbonates. We attribute the nonequilibrium morphology to coprecipitation of two salts and short synthesis time (25 min). Other aqueous synthesis conditions produced mixtures of carbonates with different morphologies, which changed depending on drying temperature (40 or 100 °C). In addition to aqueous solution, we used supercritical carbon dioxide for synthesis, producing a hydrated magnesium carbonate, with a nesquehonite structure, according to X-ray diffraction. This second material has smaller pores (1.01 nm) and high surface area. Due to their high surface area, these materials could be used for adsorbents and capillary transport, in addition to their potential use for carbon capture and sequestration.

Eksplorasi Material Semen untuk Pengembangan Produk Elemen Estetik

Cement is a unique material, initially as the base material with the mainfunction as an adhesive for other materials whose existence is always covered. Nowdays, the application of cement materials in interior elements appears to be more honest. Natural ash color and cement characteristics are interesting things to be exposed. The use of cement material has also grown not only limited to the elements that make up space (floors, walls and ceilings), but has stepped into space facilities (furniture) and aesthetic elements. Through a series of experiments with the "design by doing" method, experiments were carried out by giving chemical treatments such as foam agents, adding magnesium carbonate powder and adding magnesium oxide to the base materials (cement, cement + sand) to explore and discover various potentials, uniqueness, peculiarities and lighter feature as new ideas in aesthetic elements product development in interior design. The results obtained from a series of experiments showed differences in the cement concrete characteristics through its texture, shape, number and size of pores and difference in weight .

Effects of Rosin Powder Application on the Frictional Behavior Between a Finger Pad and Baseball.

Rosin powder, which is composed of magnesium carbonate powder and pine resin, is often used as a grip-enhancing agent in baseball pitching. However, the effect of rosin powder on friction at the baseball–human finger interface remains unclear. This study aimed to investigate the effect of rosin powder on the friction coefficient between a baseball and a finger using sliding friction tests. Ten young adult males participated in this study who were asked to slide the index finger of their dominant hand over the leather skin of a baseball adhered to the force sensor, which was not a real baseball pitching situation. Our findings suggest that rosin powder application stabilizes friction under both dry and wet conditions; that is there was less dependence of the friction coefficient on the normal force and less variation in the friction coefficient among individuals. For most participants, the friction coefficient was not necessarily increased by the presence of rosin powder at the finger pad–leather sheet interface under dry conditions. However, under wet conditions, rosin powder application increased the friction coefficient compared with the non-powdered condition in the large normal force condition, indicating the efficacy of rosin powder as a grip-enhancing agent.

Development, testing and microstructural study of aluminum foam in automobile application

The aluminum foam is a new class of material with low density, better corrosion, wear resistance and low thermal expansion. Their applications are in lightweight structural components, shock or sound absorbing products. The foam agents used in this process are calcium carbonate and magnesium carbonate powder. The composite aluminum foam structure is fabricated by bottom pouring stir casting furnace. The results show the energy absorption capability of the foam structures is much greater than the energy absorbed by the aluminum structure. The main aim of this project is to reduce the density and cost of the metals and to produce higher foaming by adding two blowing agents namely calcium carbonate and magnesium carbonate. These foaming materials are applied in structures and supportive columns of buildings. The results show that the fabricated component has a lower density and good mechanical properties with low-cost foaming materials.

Synthesis of Magnesium Carbonate via Carbonation under High Pressure in an Autoclave

Magnesium carbonate powders are essential in the manufacture of basic refractories capable of withstanding extremely high temperatures and for special types of cement and powders used in the paper, rubber, and pharmaceutical industries. A novel synthesis route is based on CO2 absorption/sequestration by minerals. This combines the global challenge of climate change with materials development. Carbon dioxide has the fourth highest composition in earth’s atmosphere next to nitrogen, oxygen and argon and plays a big role in global warming due to the greenhouse effect. Because of the significant increase of CO2 emissions, mineral carbonation is a promising process in which carbon oxide reacts with materials with high metal oxide composition to form chemically stable and insoluble metal carbonate. The formed carbonate has long-term stability and does not influence the earth’s atmosphere. Therefore, it is a feasible and safe method to bind carbon dioxide in carbonate compounds such as magnesite. The subject of this work is the carbonation of an olivine (Mg2SiO4) and synthetic magnesia sample (>97 wt% MgO) under high pressure and temperature in an autoclave. Early experiments have studied the influence of some additives such as sodium bicarbonate, oxalic acid and ascorbic acid, solid/liquid ratio, and particle size on the carbonation efficiency. The obtained results for carbonation of olivine have confirmed the formation of magnesium carbonate in the presence of additives and complete carbonation of the MgO sample in the absence of additives.

Structural characterization and strengthening mechanism of forsterite nanostructured scaffolds synthesized by multistep sintering method

In this study, highly porous forsterite scaffolds with interconnected porosities were synthesized using multi-step sintering (MSS) method. The starting powder was nanosized forsterite, which was synthesized from talc and magnesium carbonate powders. The phase composition, average particle size and morphology of the produced forsterite powder were characterized by X-ray diffraction technique (XRD) and transition electron microscopy (TEM). Forsterite scaffolds were produced by foamy method using polymeric sponges. MSS process including three steps was used to efficiently sinter the forsterite nanopowders without destroying the initial porous structure of polymeric sponges. The results showed that MSS technique is an efficient and appropriate procedure to produce highly porous forsterite scaffolds with pore size in the range of 100–300 μm. The compressive strength, compressive modulus and porosity of C12 specimen (sintered at 1650 °C for 1 h with subsequent annealing at 1000 °C for 1000 min) was 1.88 MPa, 29.2 MPa, and 72.4%, respectively, which is very close to that of cancellous bone. The approach studied in this research can be developed for other nanostructure ceramics to produce highly porous scaffolds with interconnected porosities for load bearing applications.

Fabrication of monticellite-akermanite nanocomposite powder for tissue engineering applications

Mechanical activation (MA) is an efficient method to synthesize nano-structured materials. This is the first report of successful synthesis of monticellite-akermanite nanocomposite from talc, calcium carbonate and magnesium carbonate powders. The raw materials were milled for 10 min, 2, 5, 10, and 20 h and then annealed in order to obtain monticellite-akermanite nanocomposite powder. The obtained powder was characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results indicated preparation of monticellite-akermanite nanocomposite powder with crystallite sizes about 30.76 ± 0.47 nm after 20 h mechanical alloying and sintering at 1200 °C for 1 h. Absence of enstatite, a phase that causes a reduction in mechanical and bioactivity properties, is an important feature of the prepared powder. The compacted samples of fabricated nanocomposite powder, sintered at 1300 °C for 3 h, exhibit significant improvements in compressive strength (60 ± 1.8 MPa) than single phase monticellite (43 ± 1.1 MPa) and hydroxyapatite (34 ± 1.4 MPa) which make it an appropriate candidate for bone tissue engineering applications.

Magnesium carbonate and rosin powders stabilize sliding motion between rubber-gloved human hand and grasped cylindrical bar

We investigated the effect of magnesium carbonate and rosin powders, conventionally used as anti-slip agents, for the ease of controlling the sliding motion of a stainless steel bar grasped vertically by a hand wearing a rubber glove. Fifteen participants were instructed to slide the stainless steel bar downward with their dominant hand and control the sliding speed to be constant by controlling their grip force, and stop the bar 0.2 m from the starting point within 5.0 s. Sliding control tests were conducted under six conditions of the interface between gloved-hand and the bar: dry without powder, dry with MgCO3 powder, dry with rosin powder, wet without powder, wet with MgCO3 powder, and wet with rosin powder. The bar sliding motion was captured and the time of arrival, total sliding distance of the bar, and standard deviation of the sliding velocity of the bar were calculated. The friction force between sliding bar and gloved-hand was estimated from the bar sliding motion. The controllability of the sliding motion of the bar was evaluated by sensory assessment. The sliding control test indicated that both powders reduced the variation in sliding velocity of the grasped bar and improved the controllability of its sliding motion compared with unpowdered dry and wet conditions. Powder application also decreased variation in the friction force between the rubber-gloved hand and the grasped bar during sliding under dry and wet conditions. These results suggest that both powders stabilize friction, thereby improving the sliding control of a grasped bar.

On the pore forming mechanism of Upsalite, a micro- and mesoporous magnesium carbonate

This work analyzes the pore forming mechanism and stability of Upsalite; an extraordinary moisture absorbing, high-surface area magnesium carbonate powder synthesised without the use of surfactants as pore forming agents. The pores in Upsalite were found to be created in a two-step process where the first step includes the formation of micropores by solvent evaporation and release of physically bound carbon dioxide, acting as an in situ pore-forming template. In the second step, the micropores expand to mesopores due to partial decomposition of organic groups on the surface of the pore walls when the material is stored in air at moderate temperatures (70°C). The resulting material has a narrow pore size distribution centered at 5nm, and the amorphous structure is stable upon storage in a humid atmosphere.It was further shown that calcination at temperatures above 250°C is required for complete removal of the organic surface groups in Upsalite. Prior to calcination, the organic groups present in the material act as barriers hindering water to induce crystallization of the bulk material. After calcination, however, Upsalite crystallizes into nesquehonite when stored at 100% relative humidity for several days. The results presented herein are expected to be useful for the development of novel surfactant-free synthesis routes of porous materials as well as for the understanding of the long-term performance of such materials.

The granulation of ternary mixtures: the effect of the solubility of the excipients.

The importance of excipient solubility in wet granulation has been shown using mixtures of lactose and boric acid containing third components of differing solubility characteristics. Sucrose dissolved in the binder solution and increased the amount of liquid available to form liquid bridges between other solid particles and therefore increased the number of solid bridges when the damp mass was dried. Thus, stronger, larger granules were formed. The results obtained with Sta-Rx 1500 and magnesium carbonate powders were also dependent upon the extent of solubility of these powders in the granulating solution.

Synthesis and characterization of spinel–forsterite nanocomposites

This is the first report of successful synthesis of pure spinel–forsterite nanocomposites from talc, alumina, and magnesium carbonate powders. Appropriate ratios of initial materials were mixed and mechanically activated in a planetary ball mill. The obtained powders were annealed at high temperatures. Pure spinel–forsterite nanocomposites with crystallites size in the range of 30–87 nm were obtained after 40 h of mechanical activation and subsequent annealing at 1200 °C for 1 h. The results of cold crushing strength (CCS) showed that the maximum strength of the fired spinel–forsterite bodies (∼67 MPa) can be obtained in those samples with 10 wt.% spinel. The bulk density (BD) and apparent porosity (AP) of these samples were 1.46% and 17%, respectively.

ENHANCEMENT MECHANISM OF NANOSTRUCTURE FORSTERITE FORMATION RATE BY MECHANICAL ACTIVATION AND AMMONIUM CHLORIDE

The single-phase nanostructure forsterite powder was successfully synthesized by mechanical activation of talc and magnesium carbonate powder mixture followed by annealing in the presence and absence of ammonium chloride. Mechanical activation was used as an efficient method for the optimization of powder properties by means of combination and uttermost homogenization of the powder mass. Besides, the presence of chlorine ion affected the forsterite formation rate via producing smaller particle size during subsequent annealing which is very important in the case of diffusion-controlled reactions. The single-phase nanostructure forsterite powder with crystallite size of about 36 nm was successfully synthesized by 10 h mechanical activation with subsequent annealing at 1000°C for 1 h. While in the presence of chlorine ion, the single-phase nanostructure forsterite powder with crystallite size of about 20 nm could be obtained by 5 h of mechanical activation with subsequent annealing at 1000°C for 2 min.

OS0111 乾燥収縮破壊の統計的性質について(OS1-3 き裂と破壊,OS-1 実験力学と計測技術1)

The cracking in the desiccating process of pastes is frequently observed and the cracking pattern is similar to the fragmentation pattern of impact fracture. In the present study, the statistical characteristics of desiccation cracking and physical properties of the paste are examined. Magnesium carbonate (MgCO_3) or calcium carbonate (CaCO_3) powder and water are used to make a paste. The results show that the number of cell caused by cracking increases with decreasing the mass and mass ratio of the paste. The statistical investigation shows that the number of the cell per unit area is proportional to power of the net mass of the paste per unit area. Therefore, power-law is observed in the observed scale. The exponents of the power-law in MgCO_3 paste and CaCO_3 paste are coincide with the coefficients of volume shrinkage.

Nanostructure effects on the bioactivity of forsterite bioceramic

Recently, forsterite (Mg 2SiO 4) has been introduced as a possible bioceramics due to its good biocompatibility. It has a better bending strength and fracture toughness than those of commercially available hydroxyapatite ceramics. In this study, nanostructure effects on the bioactivity of forsterite powder were investigated. For synthesizing forsterite powder, talc and magnesium carbonate powders were mechanically activated for various times. Then, the prepared powders were mixed with ammonium chloride (as a catalyst) and annealed at different temperatures. For bioactivity evaluation, the obtained forsterite powders were pressed in the form of tablets and then immersed in simulated body fluid (SBF). The results showed that nanostructure forsterite powder with crystallite size of about 31 nm, unlike micrometer-sized forsterite, possessed apatite formation ability and its bioactivity, biocompatibility, and good mechanical properties make it a suitable candidate for load bearing application in bone implant materials and open new horizons in tissue engineering.

Synthesis, characterization and sintering behaviour of indialite ceramic from fly ash

Indialite ceramic was prepared using fly ash and magnesium carbonate powder as precursors. The effects of sintering aids LiOH · H2O and TiO2 on its crystallization and morphology evolution were studied as well. X-ray diffraction results indicated that the formation of indialite was achieved by solid-state sintering reactions at 1200 °C for 4 h. With increasing amounts of LiOH · H2O, the viscosity decreased and β-spodumene, spinel phases started to develop at the expense of indialite. Scanning electron microscopy observations revealed that the surface of the sintered samples became smoother with higher porosity losses and grain size reduction. As the TiO2 contents increased from 4 to 10%, dauphine-twinned quartz and rutile were formed by simultaneously consuming indialite. In this process, the viscosity showed no significant changes.

Effects of fluorine ion and mechanical activation on nanostructure forsterite formation mechanism

The single-phase nanocrystalline forsterite powder was successfully synthesized by mechanical activation of talc and magnesium carbonate powder mixture followed by annealing in the presence and absence of fluorine ion. Simultaneous thermal analysis (STA), X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic absorption spectrometry (AAS), and transmission electron microscopy (TEM) techniques were utilized to characterize the synthesized powders. The results showed that fluorine ion affected the mechanism of forsterite formation through producing some intermediate compounds. Chondrodite, humite, and clinohumite formed in the presence of fluorine ion during subsequent annealing as a transition compound and enhanced the forsterite formation rate. Fluorine ion was released from the system by hydrolysis in the form of HF. The single-phase nanocrystalline forsterite powder was successfully synthesized by 5 and 10 h of mechanical activation with subsequent annealing at 1000 °C for 1 h in the presence of fluorine ion. The obtained forsterite powder had crystallite sizes of about 53 and 47 nm, respectively, under each treatment. Their particle size was less than 150 nm. In the absence of fluorine ion, forsterite was fabricated with a crystallite size of about 36 nm by 10 h of mechanical activation with subsequent annealing at 1000 °C for 1 h.

MECHANOCHEMICAL SYNTHESIS OF SINGLE PHASE NANOCRYSTALLINE FORSTERITE POWDER

Pure nanocrystalline forsterite ( Mg 2 SiO 4) powder was successfully synthesized by mechanochemical route and subsequent annealing. The starting materials were talc ( Mg 3 Si 4 O 10( OH )2) and magnesium carbonate ( MgCO 3) powders. To produce forsterite powder, first talc and magnesium carbonate powders were calcined at 1200°C for 1 h and 700°C for 2 h, respectively. After that the mixture of obtained powders was milled by a planetary ball mill, and then annealed at 1000°C and 1200°C for 1 h. Thermogravimetric (TG) analysis, X-ray diffraction (XRD), and scanning electron microscopy (SEM) techniques were utilized to characterize the initial and prepared powders. The results showed that a single phase nanocrystalline forsterite powder with a crystallite size of 49 nm was obtained after 40 h milling and subsequent annealing at 1000°C for 1 h.

Mechanical activation assisted synthesis of pure nanocrystalline forsterite powder

Single phase nanocrystalline forsterite powder was successfully synthesized by mechanical activation of talc and magnesium carbonate powder mixture followed by annealing. Simultaneous thermal analysis (STA), X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques were utilized to characterize the as-milled and annealed samples. The results showed that a single phase nanocrystalline forsterite with a crystallite size of 35 nm was obtained by annealing of 10 h ball milled sample at 1000 °C for 1 h. Further milling had no significant effect on structure and crystallite size of forsterite phase. Atomic absorption spectrometry (AAS) analysis showed that the amount of Fe and Cr in 100 h ball milled sample were 0.2838% and 0.00175%, respectively.