Addition Of Sodium Sulfate Research Articles

Resistance of cellular variants of Nicotiana tabaccum L. plants to water stress

Aim. It has been established that resistance to some heavy metal cations is combined with resistance to osmotic stress. Thus, resistance to barium cations correlates with resistance to water stress. Therefore, the aim of the experiment was to compare the resistance of primary and secondary calli to modelled stresses. Methods. The object of testing was tobacco, a plant sensitive to water deficit. The level of resistance of the variants was assessed by the relative increase in fresh weight under osmotic stresses: (salinity, 25.0 g/l of sea water salts; sodium sulphate, water stress). Both concentrations are lethal for wild-type tobacco cell cultures. Results. Вa-resistant tobacco cell cultures were obtained. Tobacco callus were resistant to lethal modelled stresses. The Ba-resistant culture was developed on medium with the addition of sea water salts and sodium sulphate. Conclusions. The phenomenon of resistance was selected as a result of primary selection on the medium with heavy metal ions. The level of osmotic resistance did not decrease with increasing cultivation time.

Recovery of ferronickel by green selective reduction of nickel laterite

Abstract The conversion of nickel laterite into ferronickel is commonly done through a high-temperature pyrometallurgical process that utilizes fossil fuels, which leads to environmental emissions. In order to deal with this, a biomass-based selective reduction process is proposed that uses palm shell charcoal (PSC) as the reductant. In this study, we investigate how to selectively reduce saprolytic nickel ore in various conditions, including pelletization, reduction at 1150°C for one hour, and wet magnetic separation. The optimal conditions, determined with 0.3 stoichiometric carbon, yielded a nickel content and recovery of 22.778 wt.% and 27.541 wt.%, respectively. Phases identified in the reduced pellet include forsterite, diopside, ferronickel, troilite, and olivine. Adjusting stoichiometry influences nickel concentration, resulting in increased recovery; however, excessive stoichiometry intensifies iron metallization, reducing nickel content. The addition of sodium sulfate affects nickel and iron recovery by promoting FeS phase formation, resulting in reduced iron recovery.

Mechanical properties of sisal fiber-reinforced fly ash cement mortar activated by sodium sulfate

The substantial use of fly ash as cement replacement to reduce carbon emissions is identified as the primary goal, 50 % of the cement was substituted with fly ash and in order to avoid the low early stage mechanical properties of the composite, varying doses of sodium sulfate were used as an activator of fly ash. Additionally, sisal fibers were chosen to enhance the flexural strength. The results indicate that sodium sulfate significantly enhances the early stage mechanical performance of the cementitious composites and the matrix exhibits the optimal mechanical performance at 4 wt% sodium sulfate dosage (4SS). The addition of sisal fibers resulted in an enhancement of the flexural performance of the material. The collaboration between sodium sulfate and sisal fibers results in an improvement in the initial flexural performance of the material while preserving its compressive strength. The single-fiber pullout test further confirmed that adding sodium sulfate enhances the fiber-matrix interface and bonding. Microstructural investigations by XRD, TGA, MIP, and SEM-EDS revealed accelerated hydration and early formation of a large amount of ettringite due to the addition of sodium sulfate. Ettringite acts as a gel nucleation seed, promoting the formation of a dense gel structure and effectively improving the early mechanical properties of the composite. Furthermore, with curing age, sodium sulfate also effectively improves the pore structure of the matrix in the late hydration stage.

Substantially enhanced reaction of steel slag binder stimulated by the addition of sodium sulfate and thermal treatment

An industrial by-product of steel slag has a huge potential as an alternative binder and new supplementary cementitious material (SCM). In both pure steel slag and composite systems, the amount of sulfate can be a critical factor to control early-age performance. This study aims to improve the hydration of steel slag stimulated by using a small amount of Na2SO4. The results showed that 1 % Na2SO4 enhanced both C2(A,F) and C2S hydration, leading to improved strength and denser microstructures with the formation of ettringite, AFm, and siliceous hydrogarnet. Initial thermal treatment at 40 °C with 3 % Na2SO4 provided a fast development of compressive strength at 3 days over 15 MPa. Meanwhile, an excessive amount of alkali supplied by Na2SO4 affects the relative stability between SO4-rich AFm and ettringite and has a detrimental effect on mechanical performance. The result implies that Na2SO4 content should be precisely controlled when used as a stimulator in a composite system with steel slag.

Improvement in crystallization and digestion resistance of debranched amylopectin dextrins using sodium sulfate

In this study, sodium sulfate, a typical kosmotrope salt (100–500 mM), was used to resistant dextrin crystals prepared via enzymatic debranching, and its effects on the crystallization behavior and in vitro digestibility of the dextrin crystals were investigated. Waxy maize starch was enzymatically debranched (50 °C for 24 h) and simultaneously crystallized (50 °C for 2 d) in aqueous solutions containing sodium sulfate (0–500 mM). The yield of dextrin crystals was increased using a sodium sulfate solution (84% at 500 mM sodium sulfate). The dextrin crystals comprise an A-type arrangement of double helices with higher thermal stability than native starch. Based on the DSC, XRD, and in vitro digestibility test, the high thermal stability and crystallinity of the dextrin crystals provide high resistance to digestive enzymes. The addition of sodium sulfate during crystallization increased the crystallinity and thus increased the digestion resistance. According to the in vitro digestibility test, dextrin crystals prepared with 500 mM sodium sulfate contained a resistant fraction of 80.36% in the uncooked state. After cooking (boiling), over half of the dextrin crystals remain resistant to digestive enzymes. This study showed that sodium sulfate, a typical kosmotrope salt, could accelerate the crystallization process of the debranched waxy maize starch chain, increasing yield, thermal stability, crystallinity, and digestion resistance in a short reaction period.

The role of bidirectional communication between the adipokines and the endogenous opioid system in an experimental mouse model of colitis-associated colorectal cancer.

Colorectal cancer (CRC) is one of the leading causes of death globally. Multiple factors may contribute to the pathogenesis of CRC, including the abnormalities in the functioning of the endogenous opioid system (EOS) or adiponectin-related signaling. The aim of our study was to evaluate if differences in the expression of opioid receptors (ORs) influence the development of CRC and if modulation of adiponectin receptors using AdipoRon, a selective AdipoR1 receptor agonist, affects colorectal carcinogenesis. Naltrexone, an opioid receptor antagonist, was injected intraperitoneally every second day for 2weeks, at the dose of 1mg/kg in healthy Balb/C mice to induce changes in ORs expression. CRC was induced by a single intraperitoneal injection of azoxymethane (AOM) and the addition of dextran sodium sulfate (DSS) into drinking water in three-week cycles. The development of CRC was assessed using macro- and microscopic scoring and molecular analysis (RT qPCR, ELISA)after 14 weeks. Naltrexone significantly increased the mRNA expression of Oprm1, Oprd1, and Oprk1 in the mouse colon and in the brain (non-significantly). The pretreatment of mice with naltrexone aggravated the course of CRC (as indicated by tumor area, colon thickness, and spleen weight). The level of circulatory adiponectin was lowered in mice with CRC and increased in the colon as compared with healthy mice. The β-endorphin level was increased in the plasma of mice with CRC and decreased in the colon as compared to healthy mice. AdipoRon, AdipoR1 agonist, worsened the CRC development, and pretreatment with naltrexone enhanced this negative effect in mice. CRC did not affect the expression of the Adipor1 gene, but the Adipor1 level was increased in mice pretreated with naltrexone (AOM/DSS and healthy mice). AdipoRon did not influence the expression of opioid receptors at the mRNA level in the colon of mice with CRC. The mRNA expression of Ptgs2, Il6, Nos2, Il1b, Il18, Gsdmd, and Rela was increased in mice with CRC as compared to the healthy colon. AdipoRon significantly decreased mRNA expression of Ptgs2, Il6, Il1b, and Il18 as compared to CRC mice. EOS and adiponectin-related signaling may play a role in the pathogenesis of CRC and these systems may present some additivity during carcinogenesis.

Utilization of Tamarind Seeds Extract as a Natural and Sustainable Fabric Dye

This research focuses on the use of tannin components in tamarind seed coats as a mordant and natural dye in cotton fabrics. Tannins were extracted from the tamarind seed coat by boiling method and then the tannin content was determined. The tannin extract was then used as a natural mordant with the addition of metallic copper sulfate (CuSO4) mordant. Tannin extract is also used as a dye on fabrics with the addition of sodium sulfate (NaSO4). The color strength of the tannins in the fabric was analyzed using a spectrophotometer from the rinse water. The results showed that the cloth that had been given the mordant had a stronger color strength than the cloth without the mordant. The use of mordant was varied at concentrations of 5, 10, 15, 20, and 25%-owf. The results of the analysis showed the most optimum tannin concentration at 15%-owf. The concentration of tannin used in the coloring process was also varied at concentrations of 5, 10, 15, 20, and 25%-owf. The results of the analysis show that the concentration of tannin used in the dye does not affect the strength of the color, but only affects the brightness of this color.

Sodium sulfate addition increases the bioresource of biologically active sulfated polysaccharides from Antrodia cinnamomea

Fungal sulfated polysaccharides (SPS) have been used in the pharmaceutical industry. In this study, sodium sulfate was employed as an elicitor to induce stress on the mycelia of Antrodia cinnamomea for the biosynthesis of SPS with high sulfate content. Sodium sulfate treatments increased the yield of SPS to 4.46 % and increased the sulfate content to 6.8 mmol/g of SPS. SPS were extracted from A. cinnamomea cultured with 500 mM sodium sulfate; these SPSs are denoted as Na500. Na500 exhibited the highest sulfate content and dose-dependent inhibitory activity against LPS-induced production of macrophage interleukin 6 (IL-6), tumor necrosis factor α (TNF-α), and interleukin 1β (IL-1β). Mechanistically, Na500 hindered the phosphorylation of transforming growth factor-β receptor II (TGFRII), extracellular signal-regulated kinases (ERK), and protein kinase B (AKT) expression. A purified 7.79 kDa galactoglucan, Na500 F3, augmented the anti-inflammation activity by inhibiting LPS-induced TGFβ release. Additionally, Na500 F3 restrained the LPS-induced phosphorylation of p-38, ERK, AKT, and TGFRII in RAW264.7 cells. Na500 F3 impeded the proliferation of lung cancer H1975 cells by inhibiting the phosphorylation of focal adhesion kinase, ERK, and Slug. The anti-inflammation and anticancer properties of Antrodia SPS contribute to its health benefits, suggesting its utility in functional foods.

Pore characteristics of sulfate-activated coal gasification slag cement paste backfill for mining.

With the mass production of coal-based solid waste, coal mine filling can effectively consume it. The coal gasification slag is modified and prepared as coal mine filling material to meet the relevant technical requirements, which can realize the recycling of coal mine → coal chemical industry → coal mine. In this paper, in order to explore the evolution law of the mechanical properties and pore structure characteristics of the modified coal gasification slag-cement cemented paste backfill (MCGS-CPB) prepared by sodium sulfate excitation coal gasification slag, a combined macro-meso-micro testing method is used. MCGS-CPB with different sodium sulfate contents (1~5%) were prepared and tested for uniaxial compressive strength (UCS), mercury intrusion (MIP) and microscopic tests. The results show that sodium sulfate has a significant effect on the UCS and pore structure characteristics of MCGS-CPB. The mechanical properties and pore structure characteristics of MCGS-CPB were best when sodium sulfate was doped at 3%; the mechanical properties and pore structure characteristics of MCGS-CPB were deteriorated when the addition of sodium sulfate is higher than 3%. On the meso-scale, when sodium sulfate was doped with 3%, the more harmful pores of MCGS-CPB gradually changed into harmless, less harmful, and harmful pores, and the macroscopic mechanical properties were gradually improved; when the addition of sodium sulfate is higher than 3%, the harmless, less harmful, and harmful pores of MCGS-CPB gradually changed into more harmful pores, and the macroscopic mechanical properties were deteriorated. On a microscopic scale, sodium sulfate can cause MCGS-CPB to form hydration products with expansion properties. The presence of a reasonable amount of sodium sulfate in the pores of MCGS-CPB is beneficial to the development of mechanical properties. However, excessive presence will lead to the formation of expansion stress, gradual formation of micro-expansion cracks, and deteriorate the macroscopic mechanical properties. Hence, the volcanic ash activity of coal gasification slag excited by external addition of sodium sulfate should not exceed 3%. This study provides a reference value for application ratio of sodium sulfate-stimulated MCGS-CPB used in coal mine filling design.

Influence of the Sulfur Species on the Current Efficiency and Carbon Consumption in the Aluminum Electrolysis Process

The influence of sulfur species on the current efficiency and carbon consumption in the aluminum electrolysis was investigated. Prebaked and graphite anodes with varying levels of sulfur were used. It was found that increasing the sulfur content in the anodes decreases the current efficiency and increases the carbon consumption of both types of anodes. The current efficiency decreased by 1.3 pct and the carbon consumption rose by 6.1 pct per 1 wt pct S in the prebaked anodes. The addition of sodium sulfate to the electrolyte during electrolysis with graphite anodes led to a decrease in current efficiency from 0.9 to 1.0 pct per 1 wt pct S, and to an increase in carbon consumption from 3.1 to 7.0 pct per 1 wt pct S. Electrolyte analysis showed the presence of sulfates, sulfides and polysulfides. Some link between sulfur content in the anodes and sulfur content in the electrolyte and outgoing gases was found. A comparison of the polarized and non-polarized conditions showed that the electrolysis increases the sulfur depletion from the cell and promotes the formation of soluble sulfides. Reactions of sulfur participation in redox processes have also been proposed.

Strength Improvement Using Polypropylene Fiber as Reinforcement in Natural Pozzolana-lime-stabilized Expansive Clayey Soil Artificially Contaminated by Sulfates

This paper aims to assess the behavior of the unconfined compressive strength (UCS) of polypropylene fiber (PF) reinforced natural pozzolana-lime-stabilized expansive grey clayey soil (GS) contaminated by sulfates. Lime (0–8%), natural pozzolana (NP) (0–20%), and PF (0–3%) by dry weight of soil were used. GS was contaminated by different sulfate contents (0-6%) and UCS was assessed at various curing periods (7–120 days). Results showed that adding 8% lime alone or with 20% NP considerably improved UCS. Including 1% or 2% PF as reinforcement without sulfates in lime-stabilized GS transferred stress from GS to PF due to bonding. However, increasing PF beyond 2% formed lumps, reducing contact and friction coefficient, thus decreasing UCS. This means that the optimum PF dosage was found to be 2%. The UCS of GS increased with PF content up to 2% and then decreased. The UCS significantly increased with higher calcium sulfate content and curing period due to observed cementing agents in X-ray diffraction (XRD) and scanning electron microscopy (SEM). Adverse effect of ettringite mineral on UCS caused by sodium sulfate addition was suppressed with the combination of 20% NP and 2% PF in lime-stabilized GS. Binding forces from lime and NP resisted to ettringite expansion. Sensitivity of UCS to sulfate effect was more pronounced with sodium sulfate than calcium sulfate. In addition, NP–PF mixture in lime-stabilized GS was more effective, improving the strength of expansive soil, especially with sodium sulfate. In conclusion, reinforcement of NP-lime-stabilized expansive soils with PF is an effective method.

A rapid and simple multi-residue methodology for quantification of anthelmintic macrocyclic lactones in cow, sheep and goat milk by HPLC: development, validation and application for the real samples

Anthelmintic macrocyclic lactones (MLs) [ivermectin (IVM), abamectin (ABA), doramectin (DRM), eprinomectin (EPR) and moxidectin (MXD)] are used worldwide for the treatment of parasitic infections in large and small ruminants because of their low mammalian toxicity and higher efficacy against internal and external parasites at low dose levels. A rapid, simple and sensitive HPLC and a modified QuEChERS extraction method were developed and validated for the analysis of five anthelmintic MLs residues in cow, sheep and goat milk. The analytes were extracted from milk samples by acetonitrile deproteinization, followed by the addition of sodium sulphate and sodium chloride to generate a phase partition. HPLC separation was conducted at 50⁰C using a C18 analytical column (Zorbax, Eclipse Plus, 250 mm × 4,6 mm, 5µ). The mobile phase consisted of a mixture of acetonitrile: methanol: water (58:38:4, v/v/v), delivered by an isocratic program at the flow rate of 1.3 ml/min. The elution of five analytes was completed within 11 min. The fluorescence detector (FLD) was set at an excitation wavelength of 375 nm and an emission wavelength of 470 nm. Recoveries ranged between 78.44% and 92.66%. The quantification limits (LOQ) of anthelmintic MLs in the milk samples from 3 different ruminant species ranged between 2.01 and 3.10 ng/g. The developed method was validated in accordance with the criteria of Commission Decision 2002/657/EC. Linearity, decision limit, detection and quantification limits, recovery, accuracy, precision, sensitivity and selectivity were determined, and satisfactory results were obtained. This developed and validated method is rapid, simple, sensitive and environmentally friendly, and can be used for multiple residue analyses of anthelmintic MLs in cow, sheep and goat milk for human consumption. The quantification limits for all drugs were below the maximum residue limits (MRLs), making the method appropriate for routine testing. Finally, the application of this method was assessed using real samples of cow, sheep and goat milk. The presence of MLs was confirmed in 8 out of 70 tested milk samples, which shows the method can be successfully used to determine the residue of anthelmintic MLs in three types of milk.

Effect of sodium sulfate and gypsum on performances of expansive grouting material with aluminum as expansion agent

In order to compensate the shrinkage of cement-based grout after hardening, volume expansion was produced by adding sodium sulfate or gypsum into aluminum powder blended grouting materials to enhance the expansion and strength. It was found that the addition of sodium sulfate or gypsum not only improved the expansive performances, but also enhanced the strength of specimens by increasing the amount of hydration products. When the water-cement ratio was fixed at 0.40 and aluminum powder content was at 0.5 wt‰, with the increase of sodium sulfate content, the volume expansion was accelerated, and the expansion rate gradually increased. The compressive strengths at 3d and 28d were the best at 0.5 wt%, especially the 28d compressive strength was increased by 14.7%. With the increase of gypsum content, the starting time of expansion was delayed, but the expansion rate was increased. The 3d compressive strength first increased and then decreased, and the 28d compressive strength was increased by 59.8% with 4 wt% gypsum. The mechanisms were that sodium sulfate increased the pH value of the slurry, while gypsum promoted the formation of ettringite (AFt), which caused different effects on the gas generation characteristics of aluminum powder. The results indicated that the optimum contents of sodium sulfate and gypsum in this aluminum powder blended grouting material were 0.5 wt% and 4 wt%, respectively, which had highest compressive strength and good expansion behaviors.

Improving the Thermostone Properties by Treating with Some Additives

Thermostone industry is constantly evolving After its emergence as a distinctive building material, especially in terms of thermal and sound insulation, lightness and the preference for its use in construction, due to the speed of implementation and low costs, its use as reinforced panels was developed and was not limited to block walls only, this material began to appear in some buildings as a material to fill concrete structures and a material for creating partitions, and then it was adopted as a basic building material and it will have an effective role when integrating the industry of open system building systems that can be developed. This research examines ways to enhance specifications and create a thermostone building system that, in terms of function, performance, and construction techniques, both meets the needs of regional architecture and the technical development process as a whole. The research's goal is to increase the requirements of thermostone by introducing additives like polypropylene at a rate ranging from 1 to 5%. The addition of sodium sulfate (Na2SO4) or organic fumigants (phosphine and sulfur) as well as three percentages, where 20% produced the best results. The substitution of a portion of one of its constituent materials with another component, as in the replacement of 2% of sand with fly ash powder after re-grinding it to a fineness of 75-85 micrometers to suit the mixing process and the use of white sand with a purity of up to 95%. The best results were obtained when replacing a powdered glass (the best replacement percentage is 10%). the best formation percentage is 0.12%, and the research regulated the ratios of the original thermostone ingredients, such as aluminum, with decrease and increase to achieve the best outcome.

An exploratory study of FA-based hybrid binder with alkaline sulfates as activator

Hybrid binders emerge as an intermediate solution to further decrease the clinker factor in cementitious systems without unfavorable slow development of microstructure. There is an amount of fly ash that is not yet used in the production of cementitious materials due to its limited reactivity. Therefore, by the election of an appropriate activator and small contents of Portland cement, it may be possible to provide an acceptable behaviour in terms of early-age strength and at the same time to achieve a valorization of these supplementary cementitious materials. This paper presents results of an exploratory study for the activation of a low calcium fly ash in hybrid systems. In literature previous studies have proved the synergy effect between GGBFS and FA in AAMs. For these reasons, low amounts of GGBFS with a lower carbon footprint than PC were also incorporated into some mixes. The interaction Portland cement/activator seems to control the early age behaviour. Life Cycle Assessment calculations for mortars are also presented. By comparing the different mixes in a cradle-to-gate oriented analysis, an estimation of the eco-efficiency of each of the systems was obtained. The results demonstrated that the addition of sodium sulfate was the most effective approach for hybrid binders containing FA and GGBFS, increasing not only the heat release but also the compressive strength.

Adsorption of Reactive Red 120 in Decamethyl-Cyclopentasiloxane Non-Aqueous Dyeing System

Traditional dyeing usually consumes a significant amount of water and salts, thus causing environmental pollution. Salt-free and low-water dyeing has become an important research direction in the cotton fabric dyeing industry. The non-aqueous media dyeing technology, using decamethylcyclopentasiloxane (D5) as the dyeing medium, has achieved energy saving and emission reduction in this industry. To investigate the influence of inorganic salts on the dyeing properties of reactive dyes in a non-aqueous medium dyeing system, the adsorption kinetics and level dyeing property of C.I. Reactive Red 120 were investigated at various concentrations of sodium sulfate. When no salts were included in the siloxane non-aqueous dyeing system, 80% of the reactive dye could diffuse onto the cotton fabric surface after 10 min. However, if 13% salts were added during dyeing, 87% of the reactive dye could diffuse to cotton fabric surface over the same amount of time. Moreover, the adsorption rate of dye was increased from 3.85 mg/g·min to 5.04 mg/g·min when the quantity of salts was increased from 0% to 13%. However, the concentration of sodium sulfate had minimal effect on the color depth of the dyed fabric and the final uptake of dye. But, when the concentration of sodium sulfate was significant, the level dyeing property of the dye became poor as the Sγ(λ) value was increased from 0.020 to 0.042. The adsorption kinetic of C.I. Reactive Red 120 in D5 dyeing solution may be best described by the pseudo-second-order kinetic model. As the sodium sulfate concentration increases, the half-dyeing time gradually decreases and the adsorption rate of dye increases. The repulsive force between the dye and the cotton fiber was lowered by the addition of sodium sulfate. Consequently, in the D5 dyeing system, the level dyeing property of reactive dye may be affected by the adsorption rate. Therefore, the formula of reactive dyes that do not contain salts can be applied successfully in non-aqueous dyeing systems.

Kinetics and Mechanism of Red Mud Carbothermic Reduction and Reduced Iron Grain Growth: An Influence of Sodium Sulfate

The main waste formed during the production of alumina by the Bayer method is red mud. This waste has a high content of iron, which can be effectively extracted by the carbothermic reduction and magnetic separation methods. The crucial factors affecting the commercial efficiency of this process are the iron reduction rate and the size of reduced iron particles. This study considers the influence of sodium sulfate addition to red mud on the kinetics of iron reduction and the iron grain growth process. The isothermal kinetics of the iron reduction process at 1000–1200 °C and 5–30 min of time was investigated for the red mud processing without additives and with 13.65% Na2SO4 addition. It was shown that the activation energy value for the reduction without additives was 65 kJ·mol−1, while it was 39 kJ·mol−1 for the reduction with Na2SO4 addition, respectively. Based on the microstructure study of the roasted samples, models were obtained for the calculation of the average diameter of iron grains without and with the additives. The iron grain growth process was thoroughly discussed, and its main mechanism was proposed.

Effects of sodium sulfate and potassium sulfate on the properties of calcium sulfoaluminate (CSA) cement based grouting materials

CSA cement is usually used in grouting materials because of its fast setting and high early strength properties. This paper focuses on the effects of sodium sulfate and potassium sulfate on the hydration mechanism and properties of calcium sulfoaluminate (CSA) cement based double liquid grouting materials (DLGM). A comprehensive experimental program including XRD, TG-DTA, hydration heat, scanning electron microscope (SEM) and mechanical tests were performed. The results show that both sodium sulfate and potassium sulfate accelerated the hydration of CSA cement and the formation of ettringite from the very beginning and shortened the initial and final setting time of DLGM. The changing behaviors of setting time, hydration heat and strength of DLGM with sodium sulfate and potassium sulfate were found to be different and their optimum contents were also different. The microstructure observation shows that the addition of sodium sulfate made the ettringite merged as plate-like, and potassium sulfate generated longer ettringite strips stacked together in DLGM. By considering both setting time and compressive strength, the recommended adding amounts of sodium sulfate and potassium sulfate are 3% and 1.5%, respectively. These findings could contribute to the adjustment of physical properties of DLGM.

Phase transformation and roasting kinetics of cobalt-rich copper sulfide ore in oxygen atmosphere assisted by sodium sulfate

The recovery rates of copper (99 %) and cobalt (93 %) could be significantly increased by adding sodium sulfate in activated roasting of Cobalt-rich copper sulfide (CRCS). The mechanism and kinetic parameters of CRCS roasting with sodium sulfate addition were not clear. Thus, in this study, the thermal roasting kinetics of carrollite (the predominant cobalt occurrence mineral) in CRCS adding Na2SO4 with an air atmosphere was studied in detail by TG-DTG method. The apparent activation energy (E) and pre-exponential factor (A) were obtained via Flynn-Wall-Ozawa method (FWO) and Kissinger-Akahira-Sunose method (KAS) methods, where E values were 113.89 kJ·mol−1 (KAS) and 120.87 kJ·mol−1 (FWO). The thermodynamic parameters of the roasting process were evaluated. The model function for the carrollite reaction was determined via Malek analysis. The mechanism of sodium sulfate addition in CRCS roasting was studied. Results showed that the addition of sodium sulfate in activated roasting can promote the transformation of carrollite mineral phase. The activation energy value of the oxidation process of carrollite decreases. From the kinetic point of view, the addition of sodium sulfate can promote the activation roasting.

The investigation on properties of sodium sulfate-activated mortar incorporating steel slag with various replacement ratio and particle size

The alkali-activated materials are alternatives for replacing Portland cement to manufacture concrete products, which has benefits on reducing carbon dioxide (CO2) emission and supporting the development of green sustainable construction. The combined use of steel slag (SS) and alkali activator (AA) to make alkali-activated concrete not only reuse the industrial waste but also improve the activity of SS. There are many types of chemicals can be used as AA, such as sodium silicate, sodium hydroxide, sodium carbonate and sodium sulfate (SST). In this study, SST was chosen as the AA, and the performance of alkali-activated mortar incorporating SS from 0 to 12.5% of Portland cement by mass, activated by SST with the dosage varying from 0 to 3% of cement by mass, was investigated. In addition, two types of SS, of which the particle sizes are less than 75 μm and 150 μm, were used to manufacture alkali-activated SS mortar. Flow table test, compressive strength test and flexural strength test were conducted to evaluate the fresh and hardened properties of alkali-activated steel slag (AA-SS) mortar. Response surface methodology (RSM) was used in this study as an analysis method. As result, the addition of SS tends to decrease the strength of mortar, while the addition of SST could lead to the increase in the strength of mortar.