Mineral materials as feasible amendments to stabilize heavy metals in polluted urban soils

Four minerals, agricultural limestone （AL）, rock phosphate （RP）, palygorskite （PG）, and calcium magnesium phosphate （CMP）, were evaluated by means of chemical fractions of heavy metals in soils and concentrations of heavy metals in leachates from columns to determine their ability to stabilize heavy metals in polluted urban soils. Two urban soils （calcareous soil and acidic soil） polluted with cadmium, copper, zinc and lead were selected and amended in the laboratory with the mineral materials） for 12 months. Results indicated that application of the mineral materials reduced exchangeable metals in the sequence of Pb, Cd Cu Zn. The reduction of exchangeable fraction of heavy metals in the soils amended with different mineral materials followed the sequence of CMP, PG AL RP. Reductions of heavy metals leached were based on comparison with cumulative totals of heavy metals eluted through 12 pore volumes from an untreated soil. The reductions of the metals eluted from the calcareous soil amended with the RP, AL, PG and CMP were 1.98%, 38.89%, 64.81% and 75.93% for Cd, 8.51%, 40.42%, 60.64% and 55.32% for Cu, 1.76%, 52.94%, 70.00% and 74.12% for Pb, and 28.42%, 52.74%, 64.38% and 49.66% for Zn. Those from the acidic soil amended with the CMP, PG, AL, and RP were 25.65%, 68.06%, 78.01% and 79.06% for Cd, 26.56%, 49.64%, 43.40% and 34.68% for Cu, 44.44%, 33.32%, 61.11% and 69.44% for Pb, and 18.46%, 43.77%, 41.98% and 40.68% for Zn. The CMP and PG treatments were superior to the AL and RP for stabilizing heavy metals in the polluted urban soils.

The Influence of Mineral Functional Materials on Chloride Ion Penetration of Concrete

The mechanism of chloride ion penetration in high performance concrete was analy zed. The experimental results indicate that there are two important reasons that influence the anti-chloride penetration of high performance concrete. One is the function effect of mineral functional material, so that it increases conc rete's capability to resist chloride ion penetration. The other is combined acti on of mineral functional material's original capability of binding the chloride ion (physical adsorption) and physicochemical adsorption after hydration.

Abstracts from International Journal of Minerals, Metallurgy and Materials

Crystallization behavior of F-free mold fluxes ZHANG Zuotai,WEN Guanghua,and ZHANG Yingyi Abstract The time-temperature-transformation(TTT) diagrams of F-free mold fluxes were constructed using single hot thermocouple technique(SHTT) and confocal scanning laser

Preparation and Characterization of Rare Earth Composite Materials Radiating Far Infrared for Activating Liquefied Petroleum Gas

Rare earth composite materials radiating far-infrared rays were prepared according to far infrared absorption spectrum of main component in liquefied petroleum gas (LPG). The composite materials were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), and Fourier transformed infrared spectra(FTIR). The results show that after the composite materials were calcined at 873 K for 4 h, FTIR spectra of rare earth composite materials display two new peaks at 1336 and 2926 cm-1 available for activating LPG.

Preparation and Effect of Rare Earth Composite Ceramic Materials on Reducing Exhaust Emissions

Rare earth composite ceramic materials (RE/CM) were prepared by the method of firing the mixtures of the rare earth elements, polar crystal mineral materials and clays. The effects of processing method on the reducing exhaust emissions were studied. The results show that after dealt with the ceramic balls, the surface tension of gasoline, and the CO concentration among exhaust emissions during combustion, decrease by 2.7% and 11.5%, respectively; however the temperature of the inner flue increases by 4.8%.

The Massive Sulfide Deposit of Siirt Madenkoy,South-Eastern Turkey--Geology,Geochemistry and Mineral Raw Material Potential

The Siirt Madenköy massive sulfide ore deposit has been in operation since 2005. With its approx. 39 Mt reserves (2.40% Cu), it represents the largest Cu deposit and the largest mining operation in the country (1.5 Mt ore/year). The thickness of the adjacent rocks is composed of olivine-pyroxenite basalts pillow lava, which is spilite, interchangeable ore lenses of chalcopyrite and pyrite is about 170 m and reaches a depth of 350 m. The mid-Eocene aged porphyritic, strongly altered spilites are locally interspersed with diabase and covered by conglomerates. The ores appear massive, stock work and disseminated. Main ore minerals are idiomorphic pyrite, cataclastic chalcopyrite and fine-grained magnetite. The geochemical composition of the Cu ores of the Siirt-Madenköy deposit shows in places high levels of Cu, Fe and S, as important trace elements, As, Ba, Co and Ti are listed. In relation to Clarke values, Se, Bi, Cu, Mo and Co are strongly enriched, while Na, K and Ca as well as their coherent trace elements Rb, Sr and Cd are depleted due to hydrothermal alteration. The elemental distribution is characterized by log-normal distribution, proportionality effect, high Cu/Ni ratio and significantly positive correlation between the element pairs MgO-Ni, Cr-Ni and Co/FeO-Co. The dependence of Cu and SO3 contents and Cu/FeO, SO3/FeO ratios are to be interpreted as an indication of the common origin of Cu, Fe and S. In general, Cu, Zn, Pb and S content decrease with depth, whereas those of Fe3O4 increase. The variograms of the ore distributions are characterized by hole effect, trend and zonal anisotropy, which reflect alternation of ores with host rocks and changes in elemental contents. The Siirt Madenköy deposit is attributable to Cu and Zn ratios of the Cu class of ophiolitic massive sulfide deposits. Due to the very high Cu/Pb and Cu/Zn ratios, it can be described as an analogous deposit of the mid oceanic ridge, for example comparable to ores of Galapagos Ridge. The Siirt Madenköy deposit is considered to be a syngenetic volcanogenic-exhalative massive sulfide ore deposit based on the results of the study. It belongs to the “Cyprus deposit type”. Similar deposits are Küre and Ergani-Maden in Turkey, Ermioni in Greece and Outukumpu in Finland.

Resistance to chemical attack of bittern-resisting cement in high-bittern environment

A new kind of bittern-resisting cement （BRC） was introduced. This material is based on the ternary cementitious system of clinker containing C4A3 S phase, high-activity ground granulated blast-furnace slag （GGBFS） and fly ash （FA）. The hydration process and the hydrated products of BRC were studied by means of XRD, TG-DTA and SEM, and the resistance to chemical attack of BRC in high-bittern environment was also examined. The corrosion experiment in seven kinds of brines proved that BRC exhibits an excellent resistance to chemical attack of bittern. The corrosion resistance factors were calculated and all of them were greater than 0.96. It showed that BRC totally controls the cement-based material corrosion in brines from four aspects： （1） making full use of the dominant complementation effect of mineral materials; （2） diminishing the hydrated products easy to be attacked; （3） improving the microstructure of hardened cement mortar; （4） degrading the chemical attack of bittern.

Preparation of Ultra-nano Talcum in Sand Mill and Its Application in the Polypropylene

The grinding of ultra-fine talcum powder and its application in a polypropylene （PP） matrix were investigated. Ultra-fine talcum powder was prepared by adjusting the grinding parameters of the physical milling process. The talcum powder exhibited polymodal distribution. The layered morphology of talcum particles in a horizontal sand mill was rarely damaged or destroyed. PP-talcum nanocomposites were prepared by melt blending using a twin-screw extruder. Nano talcum can be seen as a single particle, although it is not very apparent. The bending strength of talcum-filled PP was gradually increased by approximately 28%. The impact strength linearly decreased as the filler weight ratio increased. The overall maximum improvement in mechanical properties was recorded when the filler ratios increased from 15 wt% to 20 wt%.

Crack deflection occurs by constrained microcracking in nacre

For decades, nacre has inspired researchers because of its sophisticated hierarchical structure and remarkable mechanical properties, especially its extreme fracture toughness compared with that of its predominant constituent,CaCO3, in the form of aragonite. Crack deflection has been extensively reported and regarded as the principal toughening mechanism for nacre. In this paper, our attention is focused on crack evolution in nacre under a quasi-static state. We use the notched three-point bending test of dehydrated nacre in situ in a scanning electron microscope(SEM) to monitor the evolution of damage mechanisms ahead of the crack tip. The observations show that the crack deflection actually occurs by constrained microcracking. On the basis of our findings, a crack propagation model is proposed, which will contribute to uncovering the underlying mechanisms of nacre’s fracture toughness and its damage evolution. These investigations would be of great value to the design and synthesis of novel biomimetic materials.

Effect of Isobutyl-triethoxy-silane Penetrative Protective Agent on the Carbonation Resistance of Concrete

Effect of isobutyl-triethoxy-silane penetrative protective agent on the carbonation resistance of the concrete was studied.The concrete specimens for the 28 d accelerated carbonation process were manufactured with w/c of 0.49 and 0.64,both in the presence and absence of silane and mineral admixture.The penetration of isobutyl-triethoxy-silane and the carbonation of concrete were investigated by penetration depth,carbonation depth,XRD,SEM,and pore size distribution.The results showed that concrete compactness played an important role in the silane penetration and carbonation resistance.Penetration depth of silane-treated concrete mainly depended on the compactness of the concrete,and could not remarkably change through the accelerated carbonation process.In the accelerated carbonation process,penetrative protective agent improved the carbonation resistance of the higher compactness concretes but accelerated the carbonization process of the lower compactness concretes.As penetrative protective agent penetrated along the external connectivity pores into concrete not filling the entire surface area,the inorganic film could not fully protect the Ca（OH）_2 phase from carbonation.After 28 d accelerated carbonation,fibrous hydration products disappeared and the surface holes decreased.Due to the formation of carbonized products,the porosity of the concrete surface decreased,especially in high-strength concrete.

Study on the Corrosion inhibitor and Fog Suppressor for Chemical Pickling of Iron and Steel

A new type of corrosion inhibitor and fog suppressor composed of Nitrogen-containing alkaloid,water-soluble butadiene lower polymer, and inorganic electrolyte has been investigated by gravimetric and electrochemical method. Effects or this chemicals on pickling rate and hydrogen penetration into iron and steel material in 50～150 g/L HCI or/and H2SO4 solutions at 20～70℃ temperature were examined. The amount of acid fog escaping from the surface of air-liquid was determined by chemical titration. The results indicate that the efficiency of inhibition and suppression depends on film properties by which mean a barrier film on the interface of bare mild steel/solution or an unsolvable liquid membrane as hydrophibic effect.In present work the film-forming mechanism by in situ and chemistry-mechanics effect is also discussed.