Addition Of Sodium Silicate Research Articles

Effect of Silicate Additive on Structural and Electrical Properties of Germanium Nanowires Formed by Electrochemical Reduction from Aqueous Solutions.

Layers of germanium (Ge) nanowires (NWs) on titanium foils were grown by metal-assisted electrochemical reduction of germanium oxide in aqueous electrolytes based on germanium oxide without and with addition of sodium silicate. Structural properties and composition of Ge NWs were studied by means of the scanning and transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and Raman spectroscopy. When sodium silicate was added to the electrolyte, Ge NWs consisted of 1–2 at.% of silicon (Si) and exhibited smaller mean diameter and improved crystallinity. Additionally, samples of Ge NW films were prepared by ultrasonic removal of Ge NWs from titanium foils followed with redeposition on corundum substrates with platinum electrodes. The electrical conductivity of Ge NW films was studied at different temperatures from 25 to 300 °C and an effect of the silicon impurity on the thermally activated electrical conductivity was revealed. Furthermore, the electrical conductivity of Ge NW films on corundum substrates exhibited a strong sensor response on the presence of saturated vapors of different liquids (water, acetone, ethanol, and isopropanol) in air and the response was dependent on the presence of Si impurities in the nanowires. The results obtained indicate the possibility of controlling the structure and electrical properties of Ge NWs by introducing silicate additives during their formation, which is of interest for applications in printed electronics and molecular sensorics.

EFFECTIVENESS OF THE SEPARATION OF MAGNESIUM AND LITHIUM FROM SEAWATER WITH SODIUM SILICATE PRECIPITATION PROCESS

Experiments have been carried out to separate elements of magnesium and lithium from seawater to produce a lithium concentrate product that is free of magnesium through sodium silicate precipitation processes. In this study, the sample used was seawater taken from the Ancol Lagoon Area, North Jakarta. The sea water used contains 0.1674 ppm lithium ions and 1761 ppm magnesium ions with a high Mg/Li ratio of 10521. The seawater containing high levels of magnesium is not suitable as a raw material for for the manufacture of lithium carbonate (battery active ingredient) prior to initial processing. The research variable was the volume of sodium silicate solution added by 10 ml, 20 ml, 30 ml, 40 ml, 50 ml, 60 ml, 70 ml, and 100 ml which were equivalent to 13%, 27% 40%, 53%, 67%. , 80 %, 93%, and 107% stoichiometry of magnesium ion and the technique of adding sodium silicate solution included a single stage and multi-stages. From the experimental results, it can be seen that the most effective addition of sodium silicate is the addition of 80% stoichiometry. The sodium silicate precipitation process succeeded in separating magnesium ions and lithium ions from seawater as indicated by a decrease in the Mg/li ratio from 10521 to 64. The obstacle in this study was that there were still many lithium ions that were also precipitated with magnesium silicate during the precipitation process so that the lithium lost in the filtrate reached 82.26% in the single stage process. Therefore, a multi-stage process was carried out with 6 stages of the process that the addition of sodium silicate for each stage was 1/6 of the volume of sodium silicate solution at single stage optimum conditions. The results obtained from the multi-stage process were able to reduce the lithium ion lost in the filtrate to 76.54%. From the results of the study, it can be concluded that efforts to reduce the percentage of lithium ions lost in the filtrate product need to be carried out through the development of a sodium silicate precipitation process.

Effect of matrix composition on the flowability of spray-dried detergent powders

The flowability of spray-dried laundry detergent is important for manufacturing process performance and reliability, and product quality; it is strongly dependent on formulation. In this work, a detailed study of four model formulations provides fundamental understanding of the role of particle composition, and micro-structure, on spray-dried detergent powder flow behaviour. All spray-dried powders studied contained the sodium salt of linear alkylbenzene sulphonate (NaLAS) and sodium sulphate. However, their formulation varied depending on either the initial water content (30.0 or 63.0wt%) of the slurry or the addition of sodium silicate with molar-ratios of 1.6 and 2.35 SiO2:Na2O. The nil-silicate powder, made from low water content slurry, had the poorest flow characteristics. The addition of the silicate binder, significantly improved flowability, 2.35 ratio silicate, providing better flowability than 1.6 ratio. Remarkably, increasing the water content of the slurry also improved flowability significantly. Detail analysis showed that this was due to changes in composition and micro-structure of the composite matrix formed on drying the liquid components of the slurry, and that the improved flowability was due to improvements in mechanical strength of this matrix. These changes in mechanical robustness were significantly more important to the flowability than the powder shape.

SYNTHESIS OF BACTERICIDAL MICROFILTRATION CERAMIC MEMBRANES

Membrane technologies have become widely used in filtration and separation processes in chemical, oil, food, pharmaceutical, medical, environmental, textile industries, etc. Recently, there is a growing demand for the use of bactericidal membranes due to their effectiveness in neutralizing microorganisms. The aim of this work is to synthesize microfiltration ceramic membranes modified with silver nanoparticles to provide them with bactericidal properties. In this work, ceramic membranes are synthesized by dry pressing followed by sintering from natural raw materials of Ukrainian origin, namely: kaolin and saponite, as well as with the addition of silicon carbide, sodium silicate, and calcium carbonate. To provide ceramic membranes with bactericidal properties, they were modified with particles of silver. The synthesized ceramic membranes were characterized by X-ray diffraction and fluorescence analysis, and their bactericidal ability has been established. The ceramic filtration membranes after modification by silvers exhibited an inhibitory effect on the growth of Gram-positive (B. subtilis.) and Gram-negative (Escherichia coli) pathogens. Thus, the obtained bactericidal ceramic membranes are of great interest for their use for biofouling control.

Effect of Stabilizer on Gold Leaching with Thiourea in Alkaline Solutions

The present work investigated the comparison of the effects of Na2SO3 and Na2SiO3 on thiourea stabilization, and a systematic study was undertaken to establish the effects of these stabilizers on the stability of alkaline thiourea, both qualitatively and quantitatively. The effects of these stabilizers on the activation energy of alkaline thiourea gold leaching was also studied. The results showed that sodium silicate was more suitable as a stabilizer in this system than sodium sulfite because the peak current of gold dissolution with sodium sulfite was higher than that with sodium silicate, but the inhibition of thiourea decomposition by the former was less obvious than that of sodium silicate in the cyclic voltammetry curve. The quartz crystal microbalance results showed that the quality decreased to about 100 ng cm2 in the presence of a stabilizer, while it increased to 300 ng cm2 in the absence of the stabilizer. It is inferred that gold can be dissolved by alkaline thiourea in the presence of a stabilizer, while it cannot without a stabilizer because of the decomposition of thiourea. This assumption was confirmed by atomic force microscopy measurements. The surface activation energy of Au dissolution decreased from 183.76 to 98.07 kJ/moL with the addition of sodium silicate, indicating that Au dissolution was promoted with the chemical.

Synthesis and integration of cement-based capsules modified with sodium silicate for developing self-healing cements

Encapsulated healing agents comprise an emerging technology that aim to extend the service life of critical infrastructure and reduce the environmental impact of the construction industry. This paper focuses on the development and characterization of cement-based macro-capsules, made by the pan-coating technique, consisted of a reactive OPC core and a durable shell produced by the reaction of OPC with sodium silicate (SS). Two types of capsules in the range of 2–5 mm were produced in order to evaluate the effect of SS concentration on the microstructure and mechanical performance of the shell. Both types of capsules were integrated in cement mortar mixtures in different fractions (5–20%) by replacing equal sand volume. The fresh properties of the mixtures, the mechanical performance of the hardened specimens and the self-healing efficiency by means of water sorptivity were assessed and compared to the reference mixture of plain cement mortar.The results show that the addition of sodium silicate improves the crushing load of capsules under compression loading, yielding up to 75% survivability during the mixing process. The integration of capsules did not affect the rheology of the fresh mortar mixtures, while it became clear that the shell properties play a significant role on the mechanical performance of the composite mixtures. Healing assessment revealed that the addition of 20% capsules can reduce the sorptivity coefficient up to 80% after a 28 days healing period.

Extraction of magnesium from salt pond waste with low lithium grade using sodium silicate reagent

Nowadays, Indonesia’s salt production process has shifted from a traditional salt pond process to a salt pond with a geomembrane tarpaulin system. This system has the advantage of producing a faster salting process and a better salt quality and producing a thick yellow liquid waste known as bittern. The waste produced has not been fully utilized, even though the waste contains valuable elements, namely magnesium, lithium, and others. This paper investigates the potential utilization of bittern by extracting magnesium from by-product salt pond using sodium silicate reagent with various concentrations of 125–250 g/l. The bittern used in this experiment had the chemical composition as follows: 33,184 ppm magnesium (Mg), 23,787 ppm sodium (Na), 6.1 ppm lithium (Li), 5,491 ppm potassium (K), 617 ppm calcium (Ca), 152 ppm boron (B). The highest removal of magnesium ion by addition of sodium silicate of 250 g/l was about 96.2%. The results showed that the solid products were magnesium silicate precipitates without containing asbestos compounds. The magnesium silicate precipitate product can be applied as talc raw material for the pharmaceutical industry.

Nanosensing colon cancer biomarker on zeolite-modified gap-fingered dielectrodes.

Nanomaterial on the sensing area elevates the biomolecular immobilization by its right orientation with a proper alignment, and zeolite is one of the suitable materials. In this research, the zeolite nanoparticles were synthesized using rice hush ash as the basic source and the prepared zeolite by the addition of sodium silicate was utilized to attach antibody as a probe on a gap-fingered dielectrode surface to identify the colon cancer biomarker, "colon cancer-secreted protein-2" (CCSP-2). Field Emission Scanning Electron Microscopy and Field Emission Transmission Electron Microscopy images confirmed the size of the nanoparticle to be ∼15 nm and the occurrence of silica and alumina. Zeolite was modified on the electrode surface through the amine linker, and then anti-CCSP-2 was attached by an aldehyde linker. On this surface, CCSP-2 was detected and attained the detection limit to be 3 nM on the linear regression curve with 3-5 nM of CCSP-2. Estimated by the determination coefficient of y = 2.3952x - 4.4869 and R2 = 9041 with 3δ (n = 3). In addition, control proteins did not produce the notable current response representing the specific sensing of CCSP-2. This research is suitable to identify CCSP-2 at a lower level in the bloodstream under the physiological condition of a colon cancer patient.

Characteristics of Hollow Compressed Earth Block Stabilized Using Cement, Lime, and Sodium Silicate

Abstract This research aims to produce a Compressed Earth Block (CEB) product using locally available soil collected from northern Jordan. The CEB mixture was further stabilized using Portland cement, lime, and sodium silicate. The research significance is based upon the urgent need of most developing countries (e.g. Jordan, Egypt…etc) to build more durable and low-cost houses by using locally available materials. As a result, CEB was identified as a cheap and environmentally friendly construction material. CEB specimens were thoroughly characterized by studying the mechanical properties and durability characteristics. Blocks of 30 x 15 x 8 cm with two holes of 7.5 cm in diameter have a potential for higher enduring, higher compressive strength, better thermal insulation, and lower production cost. Blocks were manufactured with an addition of 8 % for either Portland cement or lime, as well as 2 % of sodium silicate to the soil. The results showed that the addition of 8 % of cement to the CEB achieves satisfactory results in both mechanical and durability properties. Also, the addition of sodium silicate was found to enhance the early-age compressive strength however it affected negatively the durable properties of blocks by increasing the erosion rate and deterioration when exposed to water.

Efficient Addition of Waste Glass in MK-Based Geopolymers: Microstructure, Antibacterial and Cytotoxicity Investigation.

Reuse of waste glass can significantly decrease the quantity of waste to be treated or disposed of in landfills, allowing to both diminish the ecological damage and to reduce the costs of transportation for removal. Geopolymer mixes with diverse percentages (20, 50 and 60 wt%) and with different grain size ranges (37 μm < diam < 53 μm; 75 μm < diam < 105 μm) of waste glass and the residual part of pure metakaolin were prepared by addition of NaOH and sodium silicate as alkaline activator solutions. The effect of waste glass on the mechanical and microstructure of new geopolymers has been explored in this study. Fourier transform infrared spectroscopy (FTIR) evidenced the reactivity of waste glass in terms of Si–O and Si–O–Al bonds, more evident for the finer waste glass powder. The consolidation of the materials has been established by reduced weight loss in water and decreased pH and ionic conductivity of the eluate after 7, 14 and 28 days of curing at room temperature. The decrease of the mechanical properties with waste glass content was less evident for the finer glassy powders, yet the value of about 4-5 MPa indicates their potential use as non-structural materials. The consolidated final materials were tested for their effects on the microbial growth of Escherichia coli and Enterococcus faecalis after 24 and 48 h, respectively. The samples showed a very limited and absent inhibition zone, for fine and coarse grain size ranges, respectively. Finally, the cytotoxicity tests accomplished the ecological valuation of the final consolidated products.

Positive Influence of Liquid Sodium Silicate on the Setting Time, Polymerization, and Strength Development Mechanism of MSWI Bottom Ash Alkali-Activated Mortars.

Setting time and mechanical properties are key metrics needed to assess the properties of municipal solid waste incineration (MSWI) bottom ash alkali-activated samples. This study investigated the solidification law, polymerization, and strength development mechanism in response to NaOH and liquid sodium silicate addition. Scanning electron microscopy and X-ray diffraction were used to identify the formation rules of polymerization products and the mechanism of the underlying polymerization reaction under different excitation conditions. The results identify a strongly alkaline environment as the key factor for the dissolution of active substances as well as for the formation of polymerization products. The self-condensation reaction of liquid sodium silicate in the supersaturated state (caused by the loss of free water) is the major reason for the rapid coagulation of alkali-activated samples. The combination of both NaOH and liquid sodium silicate achieves the optimal effect, because they play a compatible coupling role.

Effect of silicate sodium and graphene nanoplatelets on morphology and rheology characteristics of new synthesized preformed particle gel (PPG) for water shut-off treatment

Water flooding is one of the most common enhanced oil recovery (EOR) methods, however its application in naturally fractured reservoirs (NFR), suffers from the flow of water in high permeable channels and fractures which leads to low areal and volumetric sweep efficiency. Preformed Particle Gels (PPG), as a subset of gel treatments, can play a vital role in plugging super-permeable zones either near wellbore or deep in the reservoir. Nevertheless the mechanical strength and thermal stability of the designed PPGs, especially under harsh environmental conditions, are subject to further research and development. In spite of recent studies, the effects of nano-materials on the rheological and morphological properties of the PPGs are not systematically investigated and understood. In this study novel PPGs were designed and synthesized (using free radical polymerization process) for application at harsh environments in terms of temperature, pH and salinity. To investigate the effectiveness of the designed PPG samples static swelling bulk tests as well as dynamic Hele-Shaw tests are performed. The examined parameters in static tests include various pH of the environment, the type and concentration of ions in the brine, temperature, dehydration durability and presence of carbon dioxide. In addition, to enlighten the mechanisms behind the performance of the new designed PPGs, comprehensive set of rheological tests (evaluation of both storage and elastic modules) as well as SEM and ESEM image analysis of dry and swollen particles are performed. Taking advantages of silicate sodium gelation capacity and functionalization of graphene nano-platelets (GNP), novel monolithic gel samples (SNGP) with unique qualities are synthesized. Although the addition of sodium silicate and GNP reduced the swelling capacity of the gels, they have significantly improved the rheological properties of the PPG samples. Rheological tests, confirmed that by adding only 0.1 wt% graphene nano-platelets and 0.5 wt% sodium silicate, the storage module of the swollen gel increased three times. Additionally the main advantage of the samples SNGP sample is its stability at harsh conditions such as high salinity, high as well as low pH, high temperature and its dehydration durability. SEM images of dry particles shows that presence of both silicate sodium and GNP has improved the harmonization of the networked structure, with making it thicker and denser. This has increased the porous interrelated structure which in turn is responsible for strong and improved mechanical properties of the SNGP gels. ESEM images of the swollen samples shows that the uniformly porous network structure of hydrogels is led to the maximum water holding capacity, which contributes to good stability of the 3D network structure of swollen PPGs under dehydration and thermal tests. Additionally, this improved microstructure can explain the compressive strengths increment with adding up nano-graphene and silicate content. The two PPG samples with the most suitable specification in the bulk tests were selected for further performance analysis in dynamic tests through Hele-Shaw cell setup. The experimental results in this transparent fracture model showed that increasing salinity causes the increase of the residual resistance factor (Frr). The results showed that the plugging efficiency and the damage factor are directly related to the PPGs size, water salinity and concentration of both GNP and silicate sodium. It is demonstrated that SNGP sample containing 50% size of 1190–595 μm and 50% size of 297–177 μm (larger size distribution) has a higher plugging capability compared to the samples containing each of these particles sizes alone. Additionally both bulk tests and Hele-Shaw cell tests approved that synthesized PPGs are also applicable for CO 2 injection. • New PPG is synthesized to be applicable in harsh environments such as low/high pH, high salinity and high temperature. • Sodium silicate and graphene nano-platelets improved temperature resistance and dehydration durability properties. • Static swelling bulk tests and dynamic Hele-Shaw cell tests are performed to evaluate the water shut-off performance. • Different rheological tests are performed to evaluate the mechanical and rheological properties of the designed hydrogels. • SEM and ESEM are used to shed light on the morphology of the samples and the reason behind improved properties.

Nanosilicon enhances maize resistance against oriental armyworm (Mythimna separata) by activating the biosynthesis of chemical defenses.

Silicon, in its nanoscale form, has shown plant-promoting and insecticidal properties. To date, however, we lack mechanistic evidence for how nanoscale silicon influences the regulation of plant chemical defenses against herbivore attacks. To address this gap, we compared the effect of Si nanodots (NDs) and sodium silicate, a conventional silicate fertilizer, on maize (Zea mays L.) chemical defenses against the oriental armyworm (Mythimna separata, Walker) caterpillars. We found that Si NDs and sodium silicate additions, at the dose of 50mg/L, significantly inhibited the growth of caterpillars by 53.5% and 34.2%, respectively. This increased plant resistance was associated with a 44.2% increase in the production of chlorogenic acid, as well as the expression of PAL, C4H, 4CL, C3H and HCT, core genes involved in the biosynthesis of chlorogenic acid, by 1.7, 2.4, 1.9, 1.8 and 4.5 folds, respectively. Particularly, in the presence of M. separata, physiological changes in maize plants treated with 50mg/L Si NDs, including changes in shoot biomass, leaf nutrients (e.g., K, P, Si), and chemical defense compounds (e.g., chlorogenic acid, total phenolics), were higher than those of plants added with equivalent concentrations of conventional silicate fertilizer. Taken together, our findings indicate that Si, in nanoscale form, could replace synthetic pesticides, and be implemented for a more effective and ecologically-sound management of insect pests in maize crop farming.

Setting Time and Compressive Strength of Geopolymers Made of Three Indonesian Low Calcium Fly Ash with Variation of Sodium Silicate Addition

Setting Time and Compressive Strength of Geopolymers Made of Three Indonesian Low Calcium Fly Ash with Variation of Sodium Silicate Addition

Inhibition of concrete composite corrosion by combined addition of sodium nitrite and sodium silicate

Проведены исследования ингибирующих свойств нитрита натрия в комбинированной добавке с силикатом натрия при коррозии железобетона. Установлено, что повышение содержания нитрита натрия в комбинированной добавке с силикатом натрия приводит к уменьшению прочности бетона после отверждения на воздухе в течение 28 сут. Однако, при коррозии бетона, содержащего большее количество нитрита натрия в качестве ингибитора, в смеси 1%-ого раствора плавиковой кислоты (HF) и углекислоты (Н2СО3), его прочность на сжатие снижается в меньшей степени. Это подтверждается случаями частых расколов образцов при испытаниях ударно-импульсным методом. Наименьшее количество раскалываний наблюдалось у образцов, содержащих 3,2% нитрита натрия и 0,8% силиката натрия, а наибольшее – у образцов, содержащих 0,8% нитрита натрия и 3,2% силиката натрия. С помощью метода контактной коррозии построены коррозионные диаграммы стальной арматуры из стали марки Ст3 в бетоне без добавок и с комбинированными ингибирующими добавками нитрата и силиката натрия. Коррозионные диаграммы позволили определить показатели скорости коррозии стальной арматуры в бетонах с ингибирующими добавками различных составов. Добавки способствуют быстрому снижению значения плотности тока коррозии. Повышение концентрации нитрита натрия в составе ингибирующей добавки приводит к снижению скорости анодного растворения арматурной стали. Введение в бетон 3,2% нитрита натрия и 0,8% силиката натрия замедляет анодное растворение арматурной стали почти в 2 раза.

Effect of Sodium Silicate Concentration on Morphology of Ceramic Coatings Produced on Commercially Pure Aluminum Using Plasma Electrolytic Oxidation

Microstructure of ceramic coatings formed on commercially pure aluminum by plasma electrolytic oxidation using different amounts of sodium silicate was studied. Analysis of chemical composition and microhardness measurements of the coatings were carried out to characterize the morphology of the coatings. The addition of sodium silicate (1–3 g/L) increased the thickness about 8 orders of magnitude and promotes the growth of the coatings. Chemical analysis of the coatings showed that with increasing sodium silicate concentration in the electrolyte from 1 to 3 g/L, the amount of manganese in the coatings was reduced ∼12%. The contribution of aluminum and silicon changed with a reciprocal relationship. When the concentration of Na2SiO3 changed from 1 to 2 g/L, the aluminium content was reduced about 26% and silicon increased about 80%. When the concentration of Na2SiO3 changed from 2 to 3 g/L, the aluminium content increased about 38% and the concentration of silicon reduced about 60%. The microhardness of the coatings was increased about 2 orders of magnitude by increasing the concentration of sodium silicate from 1 to 3 g/L.

Effect of sodium silicate on lead release from lead service lines

The effect of sodium silicate addition on lead release from lead service lines (LSLs) was investigated using laboratory-based pipe loop experiments with LSLs harvested from a water utility that has one of the Great Lakes as its source water. The LSLs were first conditioned with a synthetic water similar to that of Buffalo Water that matched the major water chemistry that the pipes had experienced in the field; the one exception was the absence of dissolved organic carbon in the synthetic water. After conditioning, the LSLs were used in tests with the same synthetic water and with sodium silicate added to the water for half of the LSLs. In one test sodium silicate addition was performed with adjustment of the pH to maintain it at the same value (pH 7.7) as before addition. In this test sodium silicate effectively reduced the dissolved and particulate lead concentrations in the water within six weeks of treatment. Periodic assessments of the corrosion scales in the pipes found that sodium silicate accumulated throughout the scale thickness and gradually decreased the lead release. In the other test the pH was allowed to increase from 7.7 to 8.8 upon addition of 20 mg/L as SiO2 sodium silicates, and parallel control experiments were performed with the same pH increase made using sodium hydroxide addition. In these tests the lead concentrations decreased in both the silicate-treated and control pipes, and the decreases were not significantly different between the silicate-treated and control pipes.

Geosynthesis of building and construction materials through alkaline activation of granulated blast furnace slag

This article investigated the feasibility to synthesise geopolymer bricks from Granulated Blast Furnace Slag (GBFS) using alkaline activators without addition of sodium silicate or silica reactive source. Sodium hydroxide (NaOH) is a typical alkaline solution used in geopolymerisation compared to KOH with addition of silicate solution used as a catalyst to enhance the dissolution process. However, a comparative study between the two alkaline activators in the absence of silica solution are very scarce and limited. For this purpose, this article investigated the effect of type of alkali (NaOH and KOH) on unconfined compressive strength (UCS) with the aim to establish the best alkali activator that possess high activation potential and favours GBFS geopolymerisation. In addition, the effect of alkali concentration, liquid–solid ratio, curing temperature and time on the physical and mechanical properties of geopolymer bricks were investigated using UCS, SEM micrographs, XRD analysis, water absorption, and bulk density. Metal leachability and durability of the synthesised geopolymer brick was also investigated. The results show that geopolymer brick prepared with NaOH favours GBFS geopolymerisation. The optimum curing conditions that yielded the highest UCS of 72 MPa were 15 M NaOH, liquid to Solid ratio of 0,15, curing temperature and time of 80 °C and 5 days. The highest UCS was due to formation of a dense, less porous and more amorphous microstructure. The synthesised geopolymer brick met the minimum required UCS and the water absorption % to be used as facing and solid mansory brick in accordance with ASTM C126-99 and ASTM C216-07a respectively.

Improvement on combustible matter recovery in coal slime flotation with the addition of sodium silicate

The influence of an inorganic salt dispersant, sodium silicate (SS), on the removal of minerals in coal slime flotation was investigated. XRD, contact angle measurements, zeta potential measurements and EDLVO calculations were employed to reveal the interactions between SS and coal slime. The flotation experiments indicated that the combustible matter recovery of clean coal could be increased by 10.9 % with the addition of 1200 g/t SS. The reasons of SS on facilitating the separation of the combustible components from coal slime were governed by two factors, decreasing the hydrophobicity of minerals and enhancing particle dispersion, both of which are beneficial to the coal flotation. Furthermore, it was found that the effect of SS on decreasing the hydrophobicity of minerals was mainly attributed to the surface modification on kaolinite. It was concluded that SS could significantly improve the flotation recovery of coal slime especially under the condition of a high content of kaolinite in coal slime.

Electromagnetic properties of FeSiCr alloy powders modified with amorphous SiO2

The effects of amorphous SiO2 coating onto FeSiCr alloy powder on the electric and magnetic properties were investigated. FeSiCr alloy powder with an average particle size of 10 μm was coated with nano-sized silica powder to increase the resistivity and DC bias superposition characteristics. Inexpensive water glass (sodium silicate) was used as the raw material to form the amorphous silica layer onto the FeSiCr alloy powder surface acting as a binding and insulation layer. The amorphous silica layer thickness was about 20 nm to 50 nm. The thickness can be controlled by the amount of sodium silicate addition. The amorphous silica layer can significantly promote anti-oxidation, resistivity and DC bias superposition characteristic of the FeSiCr alloy.