Mass Ratio Of NaOH Research Articles

Highly efficient leaching of aluminum and chromium from aluminum chromium slag using NaOH-NaNO3 binary molten salt

In this study, the NaOH-NaNO3 binary molten salt was proposed as a highly efficient technique to leach aluminum and chromium from aluminum chromium slag (ACS). Various factors, such as roasting temperature, roasting time, mass ratio of NaOH (or NaNO3)/ACS, water leaching temperature and time, were adjusted to investigate their influence on the activation and extraction of aluminum-chromium resources from ACS. Moreover, the roasting activation conditions were optimized by response surface methodology, and the optimal extraction rates of alumina and chromium (88.72% and 95.64%, respectively) were obtained with the roasting temperature of 451 °C, roasting time of 3.9 h, NaOH/ACS mass ratio of 5.39:1, and NaNO3/ACS mass ratio of 0.79:1. Kinetic studies showed that the roasting process was controlled by the diffusion of the product interface. Finally, based on the comprehensive analysis of leaching data and physicochemical properties change of ACS with roasting, the mechanism of NaOH-NaNO3-ACS activation was revealed: NaOH-NaNO3 melted and encapsulated the ACS during the roasting reaction, NaOH provided a strongly alkaline environmental medium, which facilitated the decomposition of NaNO3 into NaNO2 and reactive oxygen species, thus prompting the oxidative decomposition of aluminum-chromium solid solution to form NaAlO2 and Na2CrO4, further improving the leaching rate of aluminum and chromium.

Copper and zinc extraction from underspoil waters using sulfur solution in sodium hydroxide

During the passage of atmospheric precipitates through the porous dump body, the products of oxidation of sulfide minerals are dissolved. As a result, underspoil waters with low pH values and a significant amount of dissolved metals are formed. For the most part, all types of the sewage produced by mining and processing enterprises (underspoil, colliery, pit, drainage) are combined before treatment, which leads to the formation of a common water yield with complex chemical composition. According to the existing practice, the combined flow is neutralized with lime milk, which leads to irretrievable losses of non-ferrous metals with mud after neutralization. The use of the sulfiding method as part of the tactics of locally autonomous processing makes it possible to obtain the copper and zinc commercial products suitable for further metallurgical processing. Previously, sulphides of biogenic or chemical nature, as well as hydrogen sulphide, have been used in extraction of metals in the form of sulphides. In this study, we have used sulfur solution in sodium hydroxide with a mass ratio of NaOH:S = 1:1 as an alternative to the old reagents. During the study, the sulfur consumption for copper and zinc extraction were determined. The impact of water pH on zinc extraction is shown. The pilot-scale tests have confirmed the results of laboratory studies. Proposed is a flow chart with the following main operations: copper extraction, zinc extraction and the zinc product conditioning. Copper concentrate with a copper content of 32.9% and zinc concentrate with a zinc content of 48% were obtained. In the resulting deposits, copper is in the form of covellite (CuS), and zinc is in the form of sphalerite (ZnS). Through metal extraction was 99.9% for copper and 99.5% for zinc.

SPENT EDIBLE OIL SOAP ANALYSIS ON CHEMICAL PRACTICUM ACTIVITIES IN SMA HARAPAN III DELI SERDANG

Spent edible oil is the result of repeated frying that is mostly done in the fast food industry or in household activities and generally this used cooking oil is disposed of as waste that pollutes the waters in the environment. Spent edible oil is a good ingredient for soap making because its raw material is relatively cheaper than most oils. In a simple laboratory study conducted by students of SMA Harapan III Deli Serdang, soap was made from used cooking oil using alkaline NaOH. The saponification process was carried out using used edible oil soap 0.3 parts by mass ratio of NaOH at a concentration of 30% and 1 part of used edible oil bleached with activated charcoal. The analysis of edible oil soap that has been made by determinate the value of free alkali with acid-base titration method and foam stability test. The results obtained from the determination of the foam test provide foam stability of 83.3% and free alkali content of 0.211%. This soap provides a fairly stable foam stability, but it still feels hot in the hands due to the alkaline NaOH that is used not completely soaped in the washing process. The use of edible oil into soap by students can increase knowledge and can be applied to overcome environmental pollution due to the disposal of edible oil into the environment.

Effect of oxide composition and ingredient proportions on the rheological and mechanical properties of geopolymer mortar incorporating pumice aggregate

Being a relatively newer material in construction sector, geopolymer based building materials have been of large interest for last decade. This study presents a comprehensive experimental study for assessment of the effectiveness of mix parameters and compound characteristics of the ingredients on the engineering properties of lightweight geopolymer mortar (LWGM). The investigated fresh properties are rheology and flow behavior of LWGMs. Mechanical properties of hardened LWGMs were monitored in terms of compressive and flexural strength as well as ultrasonic pulse velocity. Acidic pumice aggregate was used to reduce the unit weight of the mortar. The mix parameters taken into account are molarity of NaOH solution, the mass ratio of NaOH and Na2SiO3 solutions to fly ash (S/FA), proportions of Na2SiO3/NaOH (SS/SH), and the oxide compositions, which are percentage of Na2O, the ratios of H2O/Na2O, SiO2/Na2O, and H2O/Solid. The results indicated that SS/SH and S/FA significantly affected viscosity behavior and the fresh mortars were observed to conform well to Herscel-Bulkley rheological model with shear thinning tendency. The mechanical properties of hardened LWGMs demonstrated strong correlation with oxide compositions.

Product Soap from Waste Cooking Oil

Waste cooking oil(WCO) is a good candidate as a material to make soap. It is typically cheaper than other oils. In this study, we have investigated the operation of produced soap from waste cooking oil. Phosphoric acid-hydration was provided for WCO degumming. The operating temperatures is 60°C, phosphoric acid concentration is 2% and 4% content of moisture is the optimum technology of degumming. The most favorable decoloring agent is activated clay, WCO and activated clay ratio of 100:5 at 70°C with 30 min treated time. The optimal technology of saponification is that the mass ratio of NaOH and WCO is 0.3:1, saponification temperature is 100°C and the concentration of NaOH is 30%.

Decomposition of mixed rare earth concentrate by NaOH roasting and kinetics of hydrochloric acid leaching process

A new clean extraction technology for the decomposition of Bayan Obo mixed rare earth concentrate by NaOH roasting is proposed. The process mainly includes NaOH roasting to decompose rare earth concentrate and HCl leaching roasted ore. The effects of roasting temperature, roasting time, NaOH addition amount on the extraction of rare earth and factors such as HCl concentration, liquid-solid ratio, leaching temperature and leaching time on the dissolution kinetics of roasted ore were studied. The experimental results show that when the roasting temperature is 550 °C and the roasting time is 60 min, the mass ratio of NaOH:rare earth concentrate is 0.60:1, the concentration of HCl is 6.0 mol/L, the ratio of liquid to solid (L/S) 6.0:1.0, and the leaching temperature 90 °C, leaching time 45 min, stirring speed 200 r/min, and the extraction of rare earth can reach 92.5%. The relevant experimental data show that the process of HCl leaching roasted ore conforms to the shrinking core model, but the control mechanism of the chemical reaction process is different when the leaching temperature is different. When the leaching temperature is between 40 and 70 °C, the chemical reaction process is controlled by the diffusion of the product through the residual layer of the inert material. The average surface activation energy of the rare earth element is Ea = 9.96 kJ/mol. When the leaching temperature is 75–90 °C, the chemical reaction process is controlled by the interface transfer across the product layer (product layer interface mass transfer) and diffusion. The average surface activation energy of rare earth elements is Ea = 41.65 kJ/mol. The results of this study have certain significance for the green extraction of mixed rare earth ore.

Optimation of Alkoxide formed step on Carboxymethyl Kappa Carrageenan synthesis

Carboxymethylation of kappa carrageenan with mono-chloroacetic acid as a reactant had been synthesized to produce carboxymethyl kappa carrageenan (CMKC). Carboxymethylation of kappa carrageenan was obtained in two steps. First, alkalization of k-carrageenan with NaOH to create alkoxy k-carrageenan, and optimization of the alkalization step, the optimization had been done include the mass ratio between NaOH and k-carrageenan and alkalization’s temperature, second, etherification of alkoxy k-carrageenan with Monochloroacetic acid (MCA) as etherification reactant, to produce CMKC. The optimal condition (2) characterization of the CMKC properties, including the degree of substitution (DS) and FTIR spectrum. The optimal condition was based on the formed degree of substitution(DS) of CMKC. The alkalization of k-carrageenan has been performed on three variations of mass ratio between NaOH: kappa carrageenan flour that dispersed in isopropanol, and then the mass ratio of NaOH: k-carrageenan that has the highest DS was used in the experiment to find the optimal alkalization temperature. To find the optimal temperature, the alkalization was performed at, 40°, 55° and 70°. The CMKC that has the highest DS value was produced when the mass ratio between NaOH mass: kappa carrageenan is 7,2:1, and the temperature of alkalization is 70°C, The DS value that reached when the CMKC synthesis had been done on the optimal alkalization condition is, 0,85.

Influence of alkaline additives on main minerals in Baotou rare earth tailings in the process of coal-based magnetizing roasting

The influence of NaOH-Ca(OH)2 on magnetizing roasting of iron minerals and on the decomposition reactions of rare earth minerals during coal-based magnetizing roasting is explored in the present work. The effect of alkaline additives was determined by means of SEM-EDS and X-ray diffraction methods in NaOH-Ca(OH)2-coal-tailings mixtures under optimal magnetizing roasting conditions (mass ratio of NaOH, Ca(OH)2, coal and tailings equal to 2.5: 4.5: 2.5: 100, roasting at 650 °C for 2.5 h). Although NaOH results in an adverse impact on magnetizing roasting of hematite, iron in silicate minerals could be released by NaOH-Ca(OH)2 additive as a form of hematite, which is further reduced to ferromagnetic magnetite. Moreover, the reduction ability of gas is improved in presence of coal and water from decomposition reaction of Ca(OH)2. Regarding the decomposition of bastanasite, no evident effect of NaOH-Ca(OH)2 is observed. The roasted products of pristine bastnasite particles are mainly composed of rare earth oxides (REO) with little fluorine, independent on the use of alkaline additives. No high purity REO were determined in the monazite particle by SEM-EDS, which is mainly decomposed into REO and REFeO3.

Surface characteristics and CO2 adsorption capacities of acid-activated zeolite 13X prepared from palm oil mill fly ash

Zeolite 13X was synthesized from palm oil mill fly ash (POMFA) using an alkaline fusion method. A zeolite 13X yield of 85% was obtained at a mass ratio of NaOH/(SiO2 and Al2O3 precursors) of 1.6, a fusion temperature of 600°C and a fusion time of 60min. Acid activation was performed on the zeolite 13X product in order to enhance its CO2 adsorption capacity. Acid activation with 4–8MHCl for 4h produced a marked increase in the mesopore and total pore volumes of the zeolite 13X. This increased mesopore volume resulted in CO2 adsorption capacities of the acid-activated zeolite 13X at 6MHCl for 4h that were 22% higher than those of the unactivated zeolite 13X and 11% higher than those of the commercial zeolite 13X. The CO2 adsorption capacity obtained was 6.42mol CO2/kg at a pressure of 403kPa and a temperature of 32°C.

Effects of Surfactants and Alkalis on the Stability of Heavy-Oil-in-Water Emulsions

Summary In this work, the effects of combining a surfactant/alkali on the stability of heavy-oil-in-water emulsions are analyzed by use of bottle testing, spinning-drop interfacial-tension (IFT) meters, microscopes, conductivity meters, zeta-potential analyzer Turbiscan laboratory expert stabilizer, and Anton Paar rheometer. The experimental results showed that the formulated surfactant (BS-12 and OP-10) had an optimal mass ratio (1:2), and the water-separation rates initially decreased sharply as the concentrations of the surfactant increased, before decreasing moderately until reaching a minimum value. The formulated alkali solution exerted a positive synergistic effect in tandem with the surfactant at low alkali concentrations. In this way, an increasing number of petroleum soaps are produced by reactions between the alkali solutions and the active components in heavy crude oil. However, the effect was reversed at high alkali concentrations, where the compression of the alkali on the electric double layer was more significant. Images of the emulsions taken with a microscope showed that the sizes of the oil droplets were the smallest when the alkali concentration was 0.2% and mass ratio of NaOH and TEA (triethanolamine) was 1:1, which indicated that the amount of petroleum soap produced reached the maximum at this point. In addition, TEA, as a type of surface-active molecule, can form cross-multiple adsorption and hydrogen-bonding structure with surfactant and petroleum soap at the water/oil interface. When the oil/water ratio was 7:3, the water-separation rate reached its lowest point 5.33% for 3 hours. In addition, the emulsion stabilized by the surfactant and the compositional alkali possesses salt tolerance and temperature resistance. When the concentration of the bivalent salt (CaCl2 and MgCl2) increased to 0.01mol·L−1, the water-separation rate was less than 20%, and when the temperature increased from 30 to 60°C, the growth of back-scattering (BS) value was less than 2%.

Preparation of silica nanoparticles from waste silicon sludge

In order to reduce the release of hazardous waste silicon sludge (WSS) into the environment, we report a novel method to transform the WSS into silica nanoparticles and simultaneously to separate abrasive silicon carbide (SiC) particles. Alkali dissolution and acid precipitation processes were utilized to prepare silica nanoparticles effectively. The alkali dissolution process was carried out by sodium hydroxide to produce sodium silicate solution, from which SiC was separated by filtration. Afterward, the silica nanoparticles were prepared by acid precipitation method using hydrochloric acid. Box–Behnken design (BBD) was used to optimize the process variables affecting the dissolution efficiency, namely, mass ratio of NaOH and WSS, reaction temperature, and reaction time, and to determine the optimum conditions for the reaction process. Ultraviolet-visible spectrophotometer was used to measure the silica concentration in the solution. Characterized by XRD, FTIR, TEM, and BET surface area analysis, the silica with average pore size (10.52nm), high specific surface area (430.9m2/g) was obtained, and the particle size was about 20–45nm.

Electrochemical Properties of Asymmetric Supercapacitors in Potassium Hydroxide Electrolyte

Three kinds of activated carbons were prepared from Taixi anthracite by NaOH activation. As-obtained activated carbons were adopted as electrode materials to construct asymmetric and symmetric supercapacitors. The electrochemical properties of as-constructed supercapacitors in aqueous electrolyte (3.0M KOH) were investigated. Results show that the asymmetric supercapacitor assembled with activated carbon of a higher specific surface area (SBET) as the positive electrode exhibits better ion diffusion behavior and higher cell gravimetric specific capacitance (Cg). This is different from the case in non-aqueous system, mainly because pseudo-capacitance rather than double-layer capacitance has a more important effect on Cg in the aqueous electrolyte. Namely, the wettability and pseudo-capacitance of activated carbons decrease with increasing mass ratio of NaOH to anthracite, which is more prominent for activated carbons used as negative electrode materials.