Leaching kinetics of zinc silicate in ammonium chloride solution

The leaching kinetics of zinc silicate in ammonium chloride solution was investigated. The effects of stirring speed （150？400 r/min）, leaching temperature （95-108 ℃, particle size of zinc silicate （61-150 μm） and the concentration of ammonium chloride （3.5-5.5 mol/L） on leaching rate of zinc were studied. The results show that decreasing the particle size of zinc silicate and increasing the leaching temperature and concentration of ammonium chloride can obviously enhance the leaching rate of zinc. Among the kinetic models of the porous solids tested, the grain model with porous diffusion control can well describe the zinc leaching kinetics. The apparent activation energy of the leaching reaction is 161.26 kJ/mol and the reaction order with respect to ammonium chloride is 3.5.

Oxygen-assisted zinc recovery from electric arc furnace dust using magnesium chloride

Electric arc furnace(EAF)dust is an important secondary resource containing metals,such as zinc(Zn)and iron(Fe).Recover-ing Zn from EAF dust can contribute to resource recycling and reduce environmental impacts.However,the high chemical stability of ZnFe_(2)O_(4)in EAF dust poses challenges to Zn recovery.To address this issue,a facile approach that involves oxygen-assisted chlorination using molten MgCl_(2)is proposed.This work focused on elucidating the role of O2 in the reaction between ZnFe_(2)O_(4)and molten MgCl_(2).The results demonstrate that MgCl_(2)effectively broke down the ZnFe_(2)O_(4)structure,and the high O2 atmosphere considerably promoted the sep-aration of Zn from other components in the form of ZnCl_(2).The presence of O2 facilitated the formation of MgFe_(2)O_(4),which stabilized Fe and prevented its chlorination.Furthermore,the excessive use of MgCl_(2)resulted in increased evaporation loss,and high temperatures pro-moted the rapid separation of Zn.Building on these findings,we successfully extracted ZnCl_(2)-enriched volatiles from practical EAF dust through oxygen-assisted chlorination.Under optimized conditions,this method achieved exceptional Zn chlorination percentage of over 97%within a short period,while Fe chlorination remained below 1%.The resulting volatiles contained 85wt%of ZnCl_(2),which can be further processed to produce metallic Zn.The findings offer guidance for the selective recovery of valuable metals,particularly from solid wastes such as EAF dust.

Indirect Determination of CTMAB with Sodium Chloride and Ammonium Thiocyanate by Floatation and Separation of Zinc

A new method for indirect determination of cetyl-trimethyl ammonium bromide (CTMAB) with NaCl and NH4SCN by floatation and separation of zinc has been studied. The study shows that Zn(II) can associate with NH4SCN and CTMAB to form insoluble ternary ion-association complex, and the precipitate can float on the surface of the liquid phase. A good linear relationship is observed between the floatation yield (E%) of Zn(II) and the amount of CTMAB. On the ground, CTMAB can be indirectly determined by determining E% of Zn(II). The results were satisfactory.

Effects of Urea Ammonium Chloride of Different Fertilization Patterns on Maize Yield and Yield Components

[Objective] To understand the application effects of urea ammonium chloride fertilizer on maize production. [Methods] A field plot experiment was conducted to study the effects of urea ammonium chloride of different fertilization patterns on summer maize yield and yield components. [Results] Urea ammonium chloride had a long fertilizer effect and the same yield-increasing effect with urea, which could im- prove the agronomic traits and economic traits of maize apparently and the applica- tion of urea ammonium chloride with nutrient reduction of 40% （namely just use urea ammonium chloride equaled 60% pure nitrogen）, had the same yield-increasing effect with urea of traditional fertilization patterns, and input-output ratio was high and the economic benefit was remarkable. [Conclusion] To provide scientific theoretical direc- tion for large area popularization and application of urea ammonium chloride.

Kinetics of simultaneous leaching of Ag and Pb from hydrometallurgical zinc residues by chloride

The leaching kinetics of silver and lead simultaneously from zinc residue by chloride was investigated.The effects of stirring speed,temperature,sodium chloride concentration,particle size and liquid/solid ratio on Ag and Pb dissolution in sodium chloride were studied.It was determined that the dissolution rates increased with increasing sodium chloride concentration,temperature and decreasing particle size.The dissolution kinetics followed a shrinking core model,with inter-diffusion through gangue layer as the rate determining step.This finding is in accordance with the apparent activation energy(E_a) of 26.8 kJ·mol^(-1)(Ag) and 26.5 kJ·mol^(-1)(Pb),and a linear relationship between the rate constant and the reciprocal of squared particle size.The orders of reaction with respect to sodium chloride concentration,temperature and particle size were also achieved.The rate of reaction based on diffusion-controlled process can be expressed by semi-empirical equations.

Effect of ammonium chloride on leaching behavior of alkaline anion and sodium ion in bauxite residue

This study focused on leaching behavior of alkaline anion and sodium in bauxite residue through ammonium chloride treatment.The results showed that the pH of bauxite residue decreased from 10.49 to 8.93,total alkaline anion(HCO3^-,CO3^2-,OH^-,AlO2^-)concentration reduced from 38.89 to 25.50 mmol/L,leaching rate of soluble sodium was 80.86%with ammonium chloride addition of 0.75%,liquid/solid(L/S)ratio of 3(mL/g),temperature of 30°C and reaction time of 18 h;L/S ratio was the main factor affecting the removal of alkaline anion and the leaching of sodium.Furthermore,ammonium chloride promoted the dissolution of diaspore and changed the micro/morphological characteristics with the increase of massive structure.The findings of this work will contribute to achieve soil-formation of bauxite residue.

Effects of propofol on ammonium chloride-exposed astrocyte morphology and aquaporin-4 expression

Ammonia induces astrocyte swelling, which is strongly associated with overexpression of aquaporin-4. However, the mechanisms by which ammonia induces astrocyte swelling, and subsequently upregulating aquaporin-4 expression, remain unknown. In the present study, astrocytes were cultured in vitro and exposed to ammonium chloride （NH4CI）, followed by propofol protein kinase C agonist, or antagonist, respectively. Astrocyte morphology was observed by light microscopy, and aquaporin-4 expression was detected by western blot analysis. Results showed that propofol or protein kinase C agonist significantly attenuated the degree of NH4CI-induced astrocyte swelling and inhibited increased aquaporin-4 expression. Propofol treatment inhibited aquaporin-4 overexpression in cultured astrocyte induced by NH4CI; protein kinase C pathway activation is potentially involved.

Leaching of lead from zinc leach residue in acidic calcium chloride aqueous solution

A process with potentially reduced environmental impacts and occupational hazards of lead-bearing zinc plant residue was studied to achieve a higher recovery of lead via a cost-effective and environmentally friendly process. This paper describes an optimization study on the leaching of lead from zinc leach residue using acidic calcium chloride aqueous solution. Six main process conditions, i.e., the solution pH value, stirring rate, concentration of CaC12 aqueous solution, liquid-to-solid （L/S） ratio, leaching temperature, and leaching time, were inves- tigated. The microstructure and components of the residue and tailing were characterized using scanning electron microscopy （SEM） and X-ray diffraction （XRD）. On the basis of experimental results, the optimum reaction conditions were determined to be a solution pH value of 1, a stirring rate of 500 r·min-1, a CaC12 aqueous solution concentration of 400 g·L-1, a liquid-to-solid mass ratio of 7：1, a leaching tempera- ture of 80℃, and a leaching time of 45 min. The leaching rate of lead under these conditions reached 93.79%, with an iron dissolution rate of 19.28%. Silica did not take part in the chemical reaction during the leaching process and was accumulated in the residue.

Dissolution kinetics of low grade complex copper ore in ammonia-ammonium chloride solution

The leaching kinetics of Tang-dan refractory low grade complex copper ore was investigated in ammonia-ammonium chloride solution.The concentration of ammonia and ammonium chloride,the ore particle size,the solid-to-liquid ratio and the temperature were chosen as parameters in the experiments.The results show that temperature,concentration of ammonia and ammonium chloride have favorable influence on the leaching rate of copper oxide ores.But,leaching rate decreases with increasing particle size and solid-to-liquid ratio.The leaching process is controlled by the diffusion of the lixiviant and the activation energy is determined to be 23.279 kJ/mol.An equation was also proposed to describe the leaching kinetics.

Cooperative Chloride Hydrogel Electrolytes Enabling Ultralow-Temperature Aqueous Zinc Ion Batteries by the Hofmeister Effect

Aqueous zinc ion batteries have high potential applicability for energy storage due to their reliable safety,environmental friendliness,and low cost.However,the freezing of aqueous electrolytes limits the normal operation of batteries at low temperatures.Herein,a series of high-performance and low-cost chloride hydrogel electrolytes with high concentrations and low freezing points are developed.The electrochemical windows of the chloride hydrogel electrolytes are enlarged by>1 V under cryogenic conditions due to the obvious evolution of hydrogen bonds,which highly facilitates the operation of electrolytes at ultralow temperatures,as evidenced by the low-temperature Raman spectroscopy and linear scanning voltammetry.Based on the Hofmeister effect,the hydrogen-bond network of the cooperative chloride hydrogel electrolyte comprising 3 M ZnCl_(2)and 6 M LiCl can be strongly interrupted,thus exhibiting a sufficient ionic conductivity of 1.14 mS cm;and a low activation energy of 0.21 e V at-50℃.This superior electrolyte endows a polyaniline/Zn battery with a remarkable discharge specific capacity of 96.5 mAh g;at-50℃,while the capacity retention remains~100%after 2000 cycles.These results will broaden the basic understanding of chloride hydrogel electrolytes and provide new insights into the development of ultralow-temperature aqueous batteries.

Flotation of kaolinite and diaspore with hexadecyl dimethyl benzyl ammonium chloride

Tertiary amine was synthesized from fatty amine and formaldehyde. And then the synthesized tertiary amine was used to react with benzyl chloride to synthesize hexadecyl dimethyl benzyl ammonium chloride (1627) at ambient pressure. Using the synthesized 1627 as collector,the flotation properties of diaspore and kaolinite were investigated by single mineral and mixed mineral test. The flotation mechanism of diaspore,kaolinite and 1627 was discussed based on FTIR spectra. The results show that the mass ratio of aluminum to silicate achieves 15.02 and the recovery of alumina in concentrate is 43.07% using 1627 as a collector. The 1627 is found to be a more effective and a promising collector for reverse flotation to remove aluminum-silicate minerals from bauxite.

Preparation and characteristic research of anhydrous magnesium chloride with dehydrated ammonium carnallite

Taking the saline lake bischofite and NH4Cl that was removed with the ammonia method and continuously followed by filtration as raw materials with a molar ratio of 1∶1 of MgCl2 to NH4Cl, ammonium carnallite was synthesized. And then the ammonium carnallite was dehydrated to some extent at 160℃ for 4 h. Ammonium carnallite reacted with ammonia at 240℃ for 150 min and the ammonation ammonium carnallite was produced. Finally, the ammonation ammonium carnallite was calcined at 750℃ into anhydrous magnesium chloride containing only 0.1%（mass fraction） of MgO. On the other hand, dehydrated ammonium carnallite was mixed with the solid ammonium chloride at mass ratio 1∶4 at high temperature and with the differential pressure of NH3 above 30.5kPa. The dehydrated ammonium carnallite of mixture was dehydrated at 410℃, and then calcined at 700℃ into anhydrous magnesium chloride with only 0.087%（mass fraction） of MgO. X-ray diffraction and electron microscopy analysis results prove that anhydrous magnesium chloride obtained by both methods hasn’t mixed phases, the particle is large and even has good dispersion, which is suitable for preparation of metal magnesium in the electrolysis.

Thermal decomposition behaviour of polyacrylamidomethyltrimethyl ammonium chloride in red mud separation process

In order to provide references for selecting highly efficient red mud flocculants, the behaviour of polyacrylamidomethyltrimethyl ammonium chloride （PATAC） in red mud separation process was investigated. PATAC was employed as a flocculant for red mud separation from the caustic aluminate liquor at 95 ℃. The used red mud was generated from Chinese diaspore bauxite in Bayer process of alumina production. And the changes of PATAC before or after being treated in caustic solution at 95 ℃ were studied by thermogravimetry （TG） and Fourier transform infrared （FTIR） spectral analysis. The results show that PATAC fails in effectively focculating red mud and PATAC is readily converted to a quaternary ammonium hydroxide （PATAH） in caustic solution. PATAH can be decomposed to a new polymer （HPATAH） even at 95 ℃. Furthermore, there is an intramolecular hydrogen bond formed in the HPATAH polymer chain with two functional groups of--CH2--OH and --CONH2. Therefore, the poor flocculation property of PATAC for red mud separation can be attributed to the thermal decomposition of PATAC in the caustic red mud slurry at 95 ℃ and the formation of intramolecular hydrogen bond in the polymer chain of HPATAH during the thermal decomposition, which causes the absorbable functional groups of PATAC to decrease greatly.

Thermodynamics of solubility of Cu_2(OH)_2CO_3 in ammonia-ammonium chloride-ethylenediamine(En)-water system

In order to decrease the evaporating rate of ammonia and increase the solubility of copper in the solution,ethylenediamine was added into the ammonia-ammonium chloride system to leach the copper-containing oxide ores.The thermodynamic model was constructed and the solubility of malachite Cu2(OH)2CO3 in the ammonia-ammonium chloride-ethylenediamine(En)-water system was calculated using the exponential computation method based on both mass balance and charge balance.It is found that the solubility of copper can be increased and the free ammonia concentration can be decreased by submitting partial ammonia with ethylenediamine.The lower free ammonia concentration in the solution is a guarantee to the lower evaporating rate of ammonia.The conditions of malachite Cu2(OH)2CO3 converting to atacamite Cu(OH)1.5Cl0.5 were also studied.A group of experiments were designed to validate the veracity of the results of the thermodynamic calculation.It is found that the thermodynamic model is reliable and it can guide the leaching process.

Dissolution Kinetics of Calcined Ulexite in Ammonium Chloride Solutions at High Solid-to-Liquid Ratios

The dissolution kinetics of calcined ulexite in ammonium chloride solutions at high solid-to-liquid ratios were investigated. In the experiments, calcination temperature, solution concentration, reaction temperature, and pre-hydration were chosen as parameters. It was observed that the dissolution rate increased with increasing calcination temperature, solution concentration, and reaction temperature, whereas it was not affected by pre-hydration. Employing graphical and statistic methods, the dissolution rate, based on homogeneous reaction model, can be given as: (1-X(B2O3))-1-1= k(c(NH4Cl))1.982t. The activation energy for the dissolution of the ulexite sample calcined at 160 ℃ was found to be 84.04 kJ·mol-1.

Zinc chloride catalyzed synthesis of 5-substituted 1H-tetrazoles under solvent free condition

Zinc chloride is an efficient and safe catalyst in the [3 ＋ 2] cycloaddition reaction of organic nitriles with sodium azide in solventless condition. The corresponding 5-substituted ^1H tetrazoles were obtained under mild conditions. This method can overcome disadvantages such as： the use of toxic metals and expensive reagents, drastic reaction conditions, water sensitivity and the presence of dangerous hydrazoic acid.

Removal of Malachite Green Dye from Aqueous Solutions onto Microwave Assisted Zinc Chloride Chemical Activated Epicarp of <i>Ricinus communis</i>

Competitive adsorption of malachite green (MG) in single and binary system on microwave activated epicarp of Ricinus communis (MRC) and microwave assisted zinc chloride activated epicarp of Ricinus communis (ZRC) were analyzed. The preparation of ZRC from Ricinus communis was investigated in this paper. Orthogonal array experimental design method was used to optimize the preparation of ZRC. Optimized parameters were radiation power of 100 W, radiation time of 4 min, concentration of zinc chloride of 30% by volume and impregnation time of 16 h, respectively. The MRC and ZRC were characterized by pHzpc, SEM-EDAX and FTIR analysis. The effect of the presence of one dye solution on the adsorption of the other dye solution was investigated in terms of equilibrium isotherm and adsorption yield. Experimental results indicated that the uptake capacities of one dye were reduced by the presence of the other dye. The adsorption equilibrium data fits the Langmuir model well and follows pseudo second-order kinetics for the bio-sorption process. Among MRC and ZRC, ZRC shows most adsorption ability than MRC in single and binary system.

Antibacterial Properties of Starch Blending with Glycidyl Trimethyl Ammonium Chloride and Potassium Sorbate Used in Medical Dressings

Starch is easy to breed bacteria,which affects its performance and application in medical dressings.In this research,antibacterial starch was prepared by physical blending method with glycidyl trimethyl ammonium chloride(GTA)and potassium sorbate as antibacterial agents.The antibacterial activities of GTA,potassium sorbate,GTA-starch and potassium sorbate-starch were investigated with the purpose of understanding the growth of bacteria in starch system.Results showed that GTA had good antibacterial activity,and the bacteriostasis rate of 0.05 g/mL GTA against Staphylococcus aureus(S.aureus)was 96.55%.The antibacterial properties of starch increased with an increase of mass fraction of potassium sorbate and then decreased with the continuously increasing of mass fraction of GTA.GTA-starch with30%GTA showed the best antibacterial activities,the bacteriostasis rate of Escherichia coli(E.coli)and S.aureus were 26.48%and20.26%,respectively;50%potassium sorbate in potassium sorbatestarch showed the best antibacterial activities,the bacteriostasis rate of E.coli and S.aureus were 67.68%and 74.75%,respectively.

Mannich-Type Reaction of Aldimines with 2-Silyloxydienes Catalyzed by Ammonium Chloride

Reaction of imines with 2-silyloxydiene catalyzed by ammonium chloride has been perfectly proceeded under environmentally friendly conditions to give Mannich-type product selectively. The reaction would proceed via Mannich-type mechanism, not cyclization/ring-opening process. Cyclopropanation of the corresponding Mannich-type product gave the precursor of prasugrel skeleton in high yield.

PI3K/Akt pathway is involved in the activation of RAW 264.7 cells induced by hydroxypropyltrimethyl ammonium chloride chitosan

We previously demonstrated that 2-hydroxypropyltrimethyl ammonium chloride chitosan(HACC)promoted the production of nitric oxide(NO)and proinflammatory cytokines by activating the mitogen-activated protein kinases(MAPK)and Janus kinase(JAK)/STAT pathways in RAW 264.7 cells,indicating good immunomodulatory activity of HACC.In this study,to further investigate the immunomodulatory mechanisms of HACC,we determined the roles of phosphatidylinositol 3-kinase(PI3K)/Akt,activating protein(AP-1)and nuclear factor kappa B(NF-κB)in HACC-induced activation of RAW 264.7 cells by the western blotting.The results suggest that HACC promoted the phosphorylation of p85 and Akt.Furthermore,c-Jun and p65 were also increased after the treatment of RAW 264.7 cells with HACC,indicating the translocation of NF-κB and AP-1 from cytoplasm to nucleus.In addition,as scanning electron microscopy(SEM)analysis shows,the cell morphology changed after HACC treatment.These findings indicate that HACC activated MAPK,JAK/STAT,and PI3K/Akt signaling pathways dependent on AP-1 and NF-κB activation in RAW 264.7 cells,ultimately leading to the increase of NO and cytokines.