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In recent years, the application of far-infrared ceramics in fuel activation, medical care, and stealth materials has attracted an increasing amount of attention. This article proposes an analytical method to determine ceramic formulation based on the chemical composition of tailings, in which the weight ratio of the iron ore tailings, calcium carbonate, and silica is 6:1:1. On this basis, 3 wt%, 5 wt%, 7 wt%, 9 wt%, and 11 wt% schorl was added to improve the far-infrared radiation performance of iron-tailing ceramics. The results showed that the far-infrared emissivity of iron-tailing ceramics was 0.887, this being lower than that of the experimental group, and the maximum value was 0.925 when 5 wt% schorl was added. The best far-infrared radiation performance obtained is summarized as being the isomorphic structure formed by substituting metal ions that changes the dipole moment between the molecules and reduces the symmetry of the crystal vibration.

Iron ore tailing (IOT) as a solid waste has attracted attention worldwide owing to the potential safety hazards and waste of resources. However, few studies focused on exploiting the structural characteristics of IOT. IOT is a special silicate mineral mixture composed of, for example, quartz, anorthite, microcline, and clinochlore which contain adjustable silica tetrahedron structures. In our research, Mn2+ was introduced to hydrothermally react with the adjustable silica tetrahedrons of IOT with the aid of sodium silicate, to provide IOT with reactive Mn-OH groups and high specific surface areas by constructing functional value-added mesoporous manganese silicate (MS) composites. It was found that the specific surface area (SBET) of IOT improved from 6.3 to 448.2 m2g−1 and achieved ideal pore size distributions after being transformed into MS composites. The composite obtained exhibited an excellent selective adsorption performance that could rapidly remove 100% methylene blue (MB) molecules from the mixed cationic dye solutions within 1 min. The adsorption behavior was well described by pseudo second-order model and Freundlich isotherm model, indicating the chemical adsorption and multi-layer adsorption. The maximum adsorption capacity was up to 217 mg g−1 (25 °C, pH = 7, adsorption time: 120 min, MB initial concentration: 400 mg L−1). Through investigation, it was found that the selective adsorptive ability is based on the hydrogen bonding and the suitable mesoporous structure for MB molecules.

In this study, rare earth/schorl composites were prepared using co-precipitation technique with Xinjiang schorl and cerium nitrate as raw materials. The phase transitions and the lattice parameters were investigated simultaneously during the heat treatment process utilizing a high temperature X-ray diffraction. The microstructures of the composites treated at 800, 850, 900 and 950 °C were characterized by scanning electron microscope, transmission electron microscope and high resolution transmission electron microscope. The results clearly indicate that the cerium ions exchanged the interfacial structure of schorl particles, which led to the reduction in phase transition temperature. The interfacial migration and mass transfer were promoted during the phase transformation, rendering a better transformation of mullite crystals from schorl.

The thermal behavior of tourmaline mineral during the whole process from solid state at room temperature to molten salt at high temperature and back to solid state at room temperature has been systematically investigated. Surface characterization based on observation of the sintering point, thermogravimetry-differential scanning calorimetry, high-temperature x-ray diffraction analysis, field-emission transmission electron microscopy, and high-temperature Raman spectrometry did not reveal any significant changes in the crystal structure of tourmaline except for a slight decrease in grain size during the heating process from room temperature to 890°C. Further increase in the temperature to 1050°C resulted in a phase transformation into cordierite along with a sharp decrease in grain size; the phase transformation was complete at 1200°C. When the temperature was decreased to 890°C, the tourmaline phase was observed to precipitate in the molten salt, and the grain size was found to grow gradually. A continuous decrease in temperature resulted in more tourmaline with slightly smaller grain size due to the pinning effect at second-phase grain boundaries.

Iron ore tailings as secondary resources have been of great importance to many countries in the world. Their compositions are similar to that of infrared emission ceramics, but there are few reports about it. In addition, tourmaline has high infrared emission properties due to its unique structure. With the purpose of expanding functional utilization of iron ore tailings, as well as reducing the production cost of far infrared ceramics, a new kind of far infrared emission ceramics was prepared by using iron ore tailings, calcium carbonate, silica, and natural tourmaline. The ceramics powders were characterized by Fourier transform infrared spectroscope, X-ray diffraction and scanning electron microscopy, respectively. The results show that after being sintered at 1065 °C, the percentage of pseudobrookite and lattice strain of samples increased with increasing the elbaite content. Furthermore, the added tourmaline was conducive to the densification sintering of ceramics. The appearance of Li–O vibration at 734.73 cm−1, as well as the strengthened Fe–O vibration at 987.68 cm−1 were attributed to the formation of Li0.375Fe1.23Ti1.4O5 solid solution, which led the average far infrared emissivity of ceramics increase from 0.861 to 0.906 within 8–14 μm.

Tourmaline/glass composite materials were prepared by sintering at 600 °C using micron-size tourmaline mineral and glass powders as raw materials. The glass has lower melting point than the transition temperature of tourmaline. The Fourier transform infrared spectroscopy showed that the far infrared emissivity of composite was significantly higher than that of either tourmaline or glass powders. A highest far infrared emissivity of 0.925 was obtained when the dosage of tourmaline was 10 wt%. The effects of the amount of tourmaline on the far infrared emission properties of composite was also systematically studied by field emission scanning electron microscope and X-ray diffraction. The tourmaline phase was observed in the composite, showing a particle size of about 70 nm. This meant that the tourmaline particles showed nanocrystallization. They distributed homogenous in the glass matrix when the dosage of tourmaline was not more than 20 wt%. Two reasons were attributed to the improved far infrared emission properties of composite: the particle size of tourmaline-doped was nanocrystallized and the oxidation of Fe2+ (0.076 nm in radius) to Fe3+ (0.064 nm in radius) took place inside the tourmaline-doped. This resulted in the shrinkage of unit cell of the tourmaline in the composite.

In recent years, using waste iron ore tailings (IOT) as a starting material to synthesize new materials has become an emerging hot topic, but the remaining challenge is the lack of effective ways to maximize the use of each component in the IOT. In this work, two novel materials including the mesoporous zincsilite composite assembled by a layered structure with flower-like morphology and the willemite composite composed of ellipsoidal particles were synthesized from high-silicon IOT via a facile one-step hydrothermal reaction process. Due to the transformation from IOT to zincsilite composite, typical mesoporous structure was formed and the specific surface area was increased by 75.1 m2 g−1. The transformation mechanisms from IOT to zinc silicate composites were proposed based on the study of the synthesis process. The zincsilite composite shows fast adsorption rate and high adsorption capacity for MB, which is mainly attributed to the emerging mesopores and special layered structure. Specifically, the removal efficiency for methylene blue exceeds 97% within 10 min, and the maximum adsorption capacity reaches up to 180.5 mg g−1, which is over 9 times higher than that of raw IOT. Furthermore, analysis of adsorption mechanism demonstrated that the adsorption process was mainly caused by the synergistic effect of both hydrogen bonding and electrostatic attraction. The excellent adsorption property endows the composite with potential application in the field of dye wastewater treatment.

The present work attempts to utilize iron tailings as the main raw materials for preparation of functional ceramics as a means of resource utilization. A new type of endothermic functional ceramics, which can be used in the field of solar energy, was prepared via semi-dry pressing followed by pressureless sintering. The results show that the functional ceramics made of 68 wt% iron tailings, 26 wt% iron ore, 3 wt% alumina, 1 wt% potash feldspar and 2 wt% kaolin, sintered at 1185 °C exhibited the best overall performance. Visual observation reveals that there were no cracks on the surface of the samples even after 20 cycles of intense thermal shock. Other attributes could be summarized as follows: Infrared emissivity in mid-infrared region: 0.85; thermal conductivity at 500 °C: 2.066 W/(m·K); flexural strength: 119.03 MPa. XRD analysis indicates that the main crystalline phases in the samples are augite, magnetite and a small amount of hematite. An increase in the proportion of iron oxide contributed to lower melting temperature of the functional ceramics, deepen color, promote densification and increase infrared emissivity. In short, the introduction of iron tailings improves the thermal and physical properties to a certain extent.

A kind of far infrared radiation ceramics was prepared by using iron ore tailings, CaCO3 and SiO2 as main raw materials, and Ce as additive. The result of Fourier transform infrared spectroscopy showed that the sample exhibits excellent radiation value of 0.914 when doping 7 wt.% Ce. Ce4+ dissolved into iron diopside and formed interstitial solid solution with it sintered at 1150 °C. The oxidation of Fe2+ to Fe3+ caused by Ce4+ led to a decrease of crystallite sizes and enhancement of Mg–O and Fe–O vibration in iron diopside, which consequently improved the far infrared radiation properties of iron ore tailings ceramics.

Rare earth (RE)/tourmaline composite materials prepared by the precipitation method are added to the ceramic raw materials at a certain percentage and sintered into RE functional ceramics with high far infrared emission features. Then the far infrared functional ceramics are used to interact with water. The influence of the ceramics on the physical parameters of water is investigated, and the effect of the activated water on the growth of Bel-7402 hepatoma cells cultured in vitro is further studied. The results indicate that, compared with the raw water, the water activated by the ceramics can inhibit the proliferation of hepatoma cells, with statistical probability P < 0.01, which means that the effect is significant. It can be explained that the water activated by the ceramics has a higher concentration of H+, which decreases the potential difference across the cell membrane to release the apoptosis inducing factor (AIF). After entering the cells, the activated water stimulates the mitochondria to produce immune substances that lead tumor cells to apoptosis.

Rare earth mineral composite materials were prepared using tourmaline and cerous nitrate as raw materials. Through characterization by scanning electron microscopy, X-ray diffraction, X-ray photo-electron spectroscopy, dynamic contact angle meter and tensiometer, and Fourier transform infrared spectroscopy, it was found that the composite materials had a better far infrared emitting performance than tourmaline, which depended on many factors such as material composition, microstructure, and surface free energy. Based on the results of the flue gas analyzer and the water boiling test, it was found that the rare earth mineral composite materials could accelerate the combustion of liquefied petroleum gas and diesel oil. The results showed that the addition of Ce led to the improvement of far infrared emitting performance of tourmaline due to the decrease of cell volume caused by the oxidation of more Fe2+ ions and the increase of surface free energy. The application of rare earth mineral composite materials to diesel oil led to a decrease in surface tension and flash point, and the fuel saving ratio could reach 4.5%. When applied to liquefied petroleum gas, the composite materials led to the enhanced combustion, improved fuel consumption by 6.8%, and decreased concentration of CO and O2 in exhaust gases by 59.7% and 16.2%, respectively; but the temperature inside the flue increased by 10.3%.

Titania composite thin films (T/TiO2) containing tourmaline particles were prepared by a sol–gel method, using alkoxide solutions as precursor. The tourmaline particles and thin films were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and so on. The effects of tourmaline on the photocatalytic activity of TiO2 were measured with methyl orange as an objective photodegradation substance. The results showed that the photocatalytic degradation of methyl orange conformed to the first-order kinetic equation and the composite thin films had better photocatalytic activity due to the cooperation of polarity and the far infrared emission of tourmaline. The T/TiO2 thin films including 0.5 wt% tourmaline exhibited better photocatalytic activity when heat-treated at 250 °C for 3 h, than pure TiO2 thin films under the ultraviolet irradiation.

A super-hydrophilic functional ceramic was prepared by adjusting the chemical components of ceramic glaze. Effect of surface free energy of ceramic glaze on oil droplet shape and its behavior in water were studied. The results show that water can spread on ceramic surface with high surface free energy, and oil droplet can aggregate rapidly and separate from the ceramic surface in water. For the ceramic with lower surface free energy, the polar shares are dependant on its easy-cleaning property. The higher the polar shares, the better the easy-cleaning property, and the easier the droplet separates from the ceramic surface in water.

The SiO2/TiO2 composite powders including mineral tourmaline powders (T/SiO2/TiO2) were prepared from a sol made by a two-step hydrolysis method, using metasilicate ester as precursor. The powders were characterized by scanning electron microscopy (SEM). The photocatalytic activity of the sample was evaluated by the photocatalytic degradation of methyl orange. The effects of heat-treatment on the photocatalytic activity were discussed. It is found that the T/SiO2/TiO2 composite powders show higher photocatalytic activity when including 10% SiO2 and 4% tourmaline. Moreover, the photocatalytic mechanism of tourmaline on the powders was proposed.

The novel composite films containing clustered TiO2 particles and fine tourmaline particles on the surface of copper webs were prepared by the sol-gel method. The microstructures of the composite films were investigated by scanning electron microscopy (SEM), and the photocatalytic activity of the films was evaluated by photocatalytic degradation of methyl orange, respectively. The results indicate that tourmaline particles can obviously influence the microstructures of TiO2 films and enhance the photocatalytic activity due to their spontaneous permanent polarity and high radiotechnology of far infrared. During preparing the composite films, the clustered TiO2 particles with lots of nano-sized ladder layers can grow on the surface of fine tourmaline particles, the thickness of ladder layer is 10 nm, and the average diameter of nano-sized TiO2 particles is 15 nm.

The acid treatment process, testing methods, microstrcture of sepiolite mineral materials and their adsorbing properties to dodecanol were studied respectively. The results show that by acid treatment to raw sepiolite thinner fibre clusters and single fibres turn up, the pore volume and the number of micropore and mesopore in sepiolite all increase, and adsorbing properties of modified sepiolite to dodecanol are improved significantly. In the combined materials of dodecanol and sepiolite prepared under the best condition, the proportion of dodecanol is 67.96%, and then it is much higher than the result calculated from traditional BET method.

Mineral black tourmaline powders were heat-treated at different temperatures. Their crystal structure was studied by X-ray diffractometer. Their infrared absorption and emission spectra before and after the heat treatment were analyzed by the Fourier transform infrared spectrometer. The corresponding fine structures were discussed in detail. The results showed that the powders possessed higher infrared emissivity at the band where they showed stronger infrared absorption. However, there is no certain correlation between the peak intensity of infrared absorption and emissivity values at the same frequency. Because of the crystal shrinkage of c-axis, the electronic transitions were stimulated between different energy levels, and the abilities of infrared absorption and emission were enhanced with increasing the temperature of heat treatment.

For the tourmaline fine powders, in view of their low polarized charge density and easily occurred neutralization, a new evaluation model on the spontaneous polarity was proposed. By adjusting the temperature and applying electric field, the polarized charge could be measured. On this basis, a portable evaluation device was designed and assembled into four parts: Voltage Input Unit, Temperature Control Unit, Sample Loading Unit, and Charge Detection Unit. Using the designed device, the property evaluation on the spontaneous polarity of tourmaline fine powders was carried out. The spontaneous polarization intensity was finally achieved. After experimental verification, the method had the characteristics of easy operation and high accuracy.

In order for industrial and mining enterprises to fast detect the quality of fine mineral powders with far infrared emission, a simple testing model was set up according to the relationship between the emission intensity of powders and their surface temperature. The corresponding testing device was designed and assembled into three parts containing Constant Temperature Heating Part, Temperature Measuring Part and Sample Loading Part. By using the tourmaline mineral powders with far infrared emission as the research object and combining Fourier transform infrared spectroscopy, the calibration for the testing device was carried out. The results showed that the far infrared emission intensity of the tourmaline powders with different mining area and particle size could be judged. The testing results exhibited correct values when compared with those from FTIR measurements.

The microstructure and far infrared emission properties of tourmaline powders eroded by hydrochloric acid were investigated. The indexes including crystal structure, unit cell volume, microstructure and infrared spectra were characterized by X-ray diffraction, transmission electron microscopy, and Fourier transform infrared spectroscopy. The results show that the crystal structure was not changed; however, the unit cell volume decreased, the angularities of tourmaline particles became smooth, and there appeared nanohollows on their surfaces. The infrared emission properties were enhanced at proper concentrations of hydrochloric acid solutions.

Tourmaline superfine powders with different particle sizes were prepared by grinding, superfine ball milling, and high-speed centrifugation. The powders were characterized by scanning electron microscopy, X-ray diffraction, dynamic contact angle meter and tensiometry, and Fourier transform infrared spectrometry. The results show that tourmaline powders exhibit improved far infrared emission properties as the particle size decreases. The increased surface free energy and proportion of the polar component are considered to play an important role for their properties. The spontaneous polarization is increased, and the dipole moment of tourmaline is stimulated to a high energy level more easily for the chemical bond vibration, so that the energy is apt to emit by transition. In the range of 2000-500 cm(-1), the emissivity values of the samples with D50 size of 2.67 microm and 0.2 microm are 0.973 and 0.991, respectively.