An investigation on the calcination kinetics of zinc carbonate hydroxide and Calsimin zinc carbonate concentrate

Nobari, Amir Hossein; Halali, Mohammad

doi:10.1016/j.cej.2006.05.008

Cited by 12 publications

(18 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, the reaction order decreases from stage 2 to 3, which is probably due to the decrease in the nucleation rate [24]. The obtained kinetic parameters agree with the values for the pure malachite [25] and zinc carbonate hydroxide, hydrozincite [26]. It should be noted that the performed analysis reveals the formal macrokinetic mechanism.…”

Section: Thermokinetic Analysissupporting

confidence: 73%

Thermokinetic investigation of binary Cu/Zn hydroxycarbonates as precursors for Cu/ZnO catalysts

et al. 2014

View full text Add to dashboard Cite

A combination of thermogravimetric analysis (TG) and differential scanning calorimetry (DSC) coupled to mass spectrometry has been applied to study the thermal decomposition of Cu/Zn hydroxycarbonates, which are used as a precursor for the active methanol synthesis catalyst. Original TG and DSC profiles and results of a formal kinetic analysis of the calcination process are compared with transformations occurring in the solid phase, which has been studied by means of in-situ XRD. A series of hydroxycarbonate precursors with different Cu/Zn molar ratios (40/60, 60/40, 80/20) was synthesized under conditions reported as optimum for catalytic performance. The samples contain primarily two crystalline phases, aurichalcite (Cu,Zn) 5 (CO 3 ) 2 (OH) 6 and zincian malachite (Cu,Zn) 2 CO 3 (OH) 2 . At least four formal decomposition stages of CO 2 and H 2 O evolution cause the major mass loss in the TG experiments. The best-fit quality for the all studied samples was obtained for a four-step competitive reaction model. The experimental TG dependences are adequately described by the n-th order equation and 3D Jander diffusion equation. The effects of the gas flow, sample mass, and water transfer conditions on the reaction pathway were studied. The presence of H 2 O vapor in the reaction feed accelerates the decomposition and dramatically changes the reaction TG profile. The decomposition enthalpy of mixed Cu/Zn (80/20) hydroxycarbonate was determined, and the formation enthalpy of the decomposition intermediate, a carbonate-modified oxide, was calculated to be ΔH f 0 =-633.7±5.6 kJ/mol.

show abstract

Section: Thermokinetic Analysissupporting

confidence: 73%

Thermokinetic investigation of binary Cu/Zn hydroxycarbonates as precursors for Cu/ZnO catalysts

et al. 2014

View full text Add to dashboard Cite

show abstract

“…Pit corrosion mechanism has been proposed to initiate the scCO 2 induced patina formation, which is supported by the morphology of the residual metallic zinc coating that indicates dissolution of hexagonal zinc crystals (Figure ) . Zinc carbonate and zinc hydroxy carbonate can be transformed into ZnO by thermal treatment . It is noteworthy that the heat treatment did not visually alter the morphology of the zinc nanowire structure (Figure ), which confirms thermal decomposition of zinc hydroxy carbonates as a valid reaction route for synthesis of ZnO nanowires .…”

Section: Resultsmentioning

confidence: 68%

“…Thermal decomposition was utilized to transform the scarcely glycine insoluble ZnCO 3 into ZnO . The zinc hydroxy carbonate and (anhydrous) zinc carbonate decompose via reactions (1) and (2)

{Zn}_{5} {({CO}_{3})}_{2} {(OH)}_{6} \to 5ZnO + {2CO}_{2} ↑ + {3H}_{2} normalO ↑

{ZnCO}_{3} \to ZnO + {CO}_{2} ↑

…”

Section: Resultsmentioning

confidence: 99%

Convenient extraction method for quantification of thin zinc patina layers

Saarimaa¹,

Kaleva

Paunikallio³

et al. 2018

Surface & Interface Analysis

View full text Add to dashboard Cite

Synthetic zinc patina was grown on galvanized steel sheets in supercritical carbon dioxide atmosphere. Different patina compounds were dissolved and quantified using a stepwise immersion and dissolution procedure. The distinct patina components, namely anhydrous zinc carbonate (a dense layer adjacent to metallic zinc) and zinc hydroxy carbonate (nanowires on the surface), were dissolved in glycine solutions, followed by quantification of Zn 2+ in the solutes by X-ray fluorescence. The zinc hydroxy carbonate nanowires were readily glycine soluble, and the anhydrous zinc carbonate showed scarce glycine solubility, which enabled their selective quantification. The amount of the remaining (anhydrous) zinc carbonate after glycine extraction was determined from the glycine-soluble zinc oxide after calcination (heat treatment for 10 minutes at 350°C). The results were verified by scanning electron microscopy imaging and Fourier transform infrared spectroscopy measurements.

show abstract

“…In the literature, it is expressed that the solid product obtained by precipitation reaction from the solution containing zinc ions is generally in the form of hydroxycarbonates, such as Zn 3 CO 3 (OH) 4 and Zn 5 (CO 3 ) 2 (OH) 6 (20,22,30,34,38). The zinc contents and the values of mass loss of these compounds are theoretically 60.5% and 59.5% for zinc, and 24.7% and 25.8% for mass loss, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…Zinc oxide, a valuable zinc compound, has more commercial importance according to zinc carbonate (20,29,30). Zinc oxide is widely used in many fields, such as paints, ceramics, catalysts, electronics, optics, rubbers, solar cell, and chemical sensors (23,(30)(31)(32)(33)(34)(35)(36)(37).…”

Section: Introductionmentioning

confidence: 99%

Recovery of Zinc Ions From the Resulting Solution after Copper Cementation with Metallic Zinc

Demirkıran

2013

Separation Science and Technology

View full text Add to dashboard Cite

In this study, recovering of zinc ions in the residual solution occurring after copper cementation by zinc metal was investigated. The zinc ions in the solution were recovered by using sodium bicarbonate as precipitation agent. After the precipitated product was separated from the solution, it was dried at 80 C for 5 h in an oven and was subjected to the calcination process to obtain zinc oxide. The XRD and SEM analyses of the precipitated and calcined products were carried out. It was determined that the precipitated solid was Zn 5 (CO 3 ) 2 (OH) 6 (hydrozincite) and the calcined product was ZnO.

show abstract

An investigation on the calcination kinetics of zinc carbonate hydroxide and Calsimin zinc carbonate concentrate

Cited by 12 publications

References 23 publications

Thermokinetic investigation of binary Cu/Zn hydroxycarbonates as precursors for Cu/ZnO catalysts

Thermokinetic investigation of binary Cu/Zn hydroxycarbonates as precursors for Cu/ZnO catalysts

Convenient extraction method for quantification of thin zinc patina layers

Recovery of Zinc Ions From the Resulting Solution after Copper Cementation with Metallic Zinc

Contact Info

Product

Resources

About