Table of Content

28 May 2022, Volume 22 Issue 5

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Cover and Contents

The Chinese Journal of Process Engineering. 2022, 22(5):  0. 

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Reviews

Research progress and application of heat transfer enhancement of twisted oval tubes

Xiuzhen LI Yingying TAN Junfei YUAN Zhanwei WANG Lin WANG

The Chinese Journal of Process Engineering. 2022, 22(5):  561-572.  DOI: 10.12034/j.issn.1009-606X.221153

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The twisted oval tube has simple structure, excellent heat transfer enhancement and anti-fouling performance, and has become one of the research hotspots in the field of passive heat transfer enhancement. In recent years, researchers have carried out a lot of research on the heat transfer performance of twisted elliptical tubes (bundles) through experiments and numerical simulations. The mechanism of heat transfer enhancement is explained.Although there are reviews on the technology of twisted oval tube exchangers, there are deficiencies in the induction of the heat transfer enhancement characteristics of twisted oval tubes and the analysis of the research clues of the engineering application. This review focuses on the internal and external heat transfer and flow resistance performance of the twisted oval tube, and summarizes the influence of the structure of the twisted oval tube (bundle), working fluid and flow state on the heat transfer performance and flow resistance characteristics. The review also reviews the engineering application cases of twisted oval tube heat exchangers, and outlines the contents to be perfected in the researches on twisted oval tubes, and prospects the development trend of the research on heat transfer intensification of twisted oval tubes. This review is expected to provide guidance and reference for deepening the theoretical research and engineering practice of twisted oval tubes.

Progress on catalysts for hydrogen production by low temperature methanol water reforming

Zhan SHEN Zhidong JIANG Pengfei ZHANG Ziyu ZHANG Haiying CHE Zifeng MA

The Chinese Journal of Process Engineering. 2022, 22(5):  573-585.  DOI: 10.12034/j.issn.1009-606X.221147

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Methanol is a promising energy carrier owing to its simple structure, high hydrogen content and huge production capacity. Methanol steam reforming (MSR) is an energy-saving and efficient on-site hydrogen production method. Combined with fuel cells, MSR can be applied in many fields. However, due to the high reaction temperature (250~300℃), there are some problems such as slow start-up, high CO content and low thermal efficiency. Low temperature methanol water reforming (LT-MWR), including LT-MSR and aqueous-phase reforming of methanol (APRM), means that the reaction proceeds below 200℃, and maintains high reaction activity, which can reduce the preheating time and the side reactions, and achieve stronger thermal coupling with fuel cells. In this review, the performance and defects of commercial catalysts are firstly introduced based on characterization results. The research of LT-MWR catalysts for hydrogen production is reviewed, including Cu-based catalysts, noble metal catalysts and photo-synergistic catalysts. The modification strategies for low temperature Cu-based catalysts are summarized, including synthesis methods, structure design and element doping. The commercial CuZnAlOx catalyst at home and abroad has the characteristics of high methanol conversion and good stability, despite its relatively high price and low activity below 200℃. Because the activity of Cu-based catalysts is greatly affected by temperature, the catalytic activity decreases sharply at low temperature. By appropriate modification, Cu-based catalysts can perform high activity at low temperature. Noble metal catalysts have high activity at low temperature, but they are expensive and the synthesis process is complex. Photo-synergistic catalysts are functional under the condition of light, which is still in the research stage. The synthesis method can strengthen the micromixing degree and reproducibility. Appropriate structure design can increase the specific surface area and thermal stability of the catalyst. Element doping enables better dispersion of active components and modifies the surface structure. Three modification strategies can effectively improve the performance of Cu-based catalyst for LT-MSR, reducing the content of CO content while maintaining high activity. Finally, the prospect and challenges of LT-MSR catalysts for hydrogen production are prospected.

Research progress on degradation of organic pollutants in water by catalytic ozonation

Shuhuan WANG Lilong ZHOU Zhengjie LI Jilong HAN Runjing LIU Jimmy YUN

The Chinese Journal of Process Engineering. 2022, 22(5):  586-600.  DOI: 10.12034/j.issn.1009-606X.221094

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For the further development of industry and improvement of living resources for everyone, the pollution of water resources is one of the urgent problems to be solved nowadays. The organic pollutants can be removed effectively by the catalytic ozonation process and the method is easy to operate, so it has been used in industry widely. The selection of catalysts has an important influence on the catalytic oxidation process of organic pollutants. In this study, the mechanism of the homogeneous catalytic ozonation process and heterogeneous catalytic ozonation process were analyzed and summarized. The catalytic effects of noble metal catalysts, transition metal catalysts, alkaline earth metal catalysts, and non-metal catalysts that have been used in heterogeneous catalytic ozonation to remove organic pollutants were summarized. The methods that have been used to improve the catalytic activity of these catalysts were also reviewed. The effects of pH value, ozone concentration, catalyst dosage, and the concentration of organic matters on the process of catalytic ozonation were summarized. It is pointed out that the main problem in the process of degradation of organic pollutants by catalytic ozonation is the loss of active components and the reduction of catalytic activity in an aqueous solution. Therefore, for future research, the development and preparation of novel catalysts with high catalytic activity and stability remain the research focus of this process.We can take the measures of improving the adsorption capacity of the catalyst, improving the transfer capacity of ozone in water, and using the synergistic coupling of different active components to effectively inhibit the loss of active components, improve the service life of the catalyst and improve the stability of the catalyst at the same time, to achieve the purpose of effective degradation of organic pollutants.

Research Paper

Effects of hole distribution on flow field and noise for multi-hole plates

Qian LI Hua JI Donglin FENG Ziyang ZHANG Zongxing DUAN

The Chinese Journal of Process Engineering. 2022, 22(5):  601-611.  DOI: 10.12034/j.issn.1009-606X.221131

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At present, the multi-hole plates with uniform hole distribution structure are widely used in the process industry to limit the flow and reduce the pressure, vibration and noise because of low manufacturing cost, simple structure, easy processing, easy installation and maintenance. In order to further improve the flow stability and reduce the flow noise, multi-hole plates of non-uniform hole distribution with different hole spacing, hole number, and hole diameter are designed with the equivalent opening diameter unchanged. Based on the numerical results, the velocity, pressure, reflux characteristics, jet convergence and flow development in the pipeline with different multi-hole plates are compared in detail to analyze the flow field characteristics. Moreover, the noise of multi-hole plates is numerically calculated by the acoustic analogy model. The observation points are set on the centerline and the section perpendicular to the flow direction to compare the spectrum characteristics and the overall sound pressure level. The numerical results show that the decrease of hole spacing with equal difference, the increase of hole number on the plate edge, and the increase of hole diameter without reducing the hole number can all effectively improve the flow stability and reduce the noise level of multi-hole plates without influencing the pressure drop ability compared with the general multi-hole plate with uniform hole distribution, and the maximum decrease of noise level is 5.62, 6.10 and 7.00 dB respectively.

Influence of aspect ratio on heat transfer enhancement performance by jet in helical duct with rectangular cross section

Yaxia LI Pengyu XU Zemin HAN Yunhang LI Fengyuan CUI Jing ZHANG

The Chinese Journal of Process Engineering. 2022, 22(5):  612-621.  DOI: 10.12034/j.issn.1009-606X.221123

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The purpose of this work is to explore fluid turbulent flow and heat transfer characteristics in the single rectangular helical duct with different aspect ratios of cross section γ. Furthermore, better heat transfer enhancement effect of the jet on the rectangular helical duct can be obtained. Computational fluid dynamic software is employed to research the turbulent flow fields, secondary flow fields and heat transfer characteristics both in the single rectangular helical duct and the helical duct mounted with a jet pipe. The jet pipe is mounted on the outer wall of the helical duct with a certain angle. Four aspect ratios of the cross section γ as 0.625, 1.1, 1.6 and 2.5 respectively are selected for the rectangular helical duct. The results show that with the same cross-section area and flow rate, a four-vortex structure of the secondary flow can be found only in the helical duct at γ≥1.6 under high Reynolds number. Secondary flow pattern under other conditions is a two-vortex structure in the studied range. For a single helical channel, the larger the γ value is, the smaller the flow resistance is and the worse the heat transfer performance is. Heat transfer capacities of the four walls on the rectangular cross section are all improved after the jet is added to the helical duct. The larger the γ value is, the more significant heat transfer enhancement effect of jet can be obtained. The average value of the local Nusselt number on the heated wall (Nulocal)m can be up to 2.51 times than that of a single helical duct when γ=2.5 and the ratio of jet velocity to the mainstream velocity εj=3.55. The comprehensive enhanced heat transfer factor PEC2 of the helical duct area under the influence of the jet is between 1.05~1.21 when the influence of the increase of jet flow rate is considered.

Analysis of flow characteristics of power law-fluid in Kenics static mixer

Jing ZHANG Sixu HUANG Can JIANG Jianhua WU Bin GONG

The Chinese Journal of Process Engineering. 2022, 22(5):  622-630.  DOI: 10.12034/j.issn.1009-606X.221164

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The purpose of this work is to explore the flow of power-law fluid in Kenics static mixer. The flow was affected by the element shearing action of Kenics static mixer. Discovery HR-2 rheometer was used to measure the consistency coefficient K and rheological index n of the carboxymethyl cellulose solution at 0.5wt%, 0.7wt% and 0.9wt%. The parameter of power-law fluid was provided for the numerical simulation. The computational fluid dynamics software Fluent was used to simulate the computational domain. The flow resistance and shear-thinning characteristic in the Kenics static mixer were experimentally measured and numerically simulated in the conditions of the element aspect ratio Ar=1.0~2.0 and the flow rate 50×10-6~450×10-6 m3/s. It was showed that the resistance coefficient of the twisted blade with Ar=2.0 was 66.6% lower and the viscosity was 9.0% higher than that with Ar=1.0. The flow research showed that the internal-flow vortex, the detour-flow vortex and the near-wall vortices were induced by twist blade. The formation and dissipation of near-wall vortices played a good role in drag reduction because the internal vorticity and shear stress were increased and the viscosity of carboxymethyl cellulose solution was effectively reduced. The longitudinal vortices enhanced the shear effect of fluid flow in the static mixer. Affected by the vortices, the highest velocity was at 45° of circumferential direction in the local flow field of the element. The highest vorticity, shear stress and the lowest viscosity were at 30° of circumferential direction. The velocity was the highest at 0.4 times radius and the viscosity was highest at 0.7 times radius. The secondary flow velocity and shear stress were improved effectively by Kenics static mixer, and the viscosity of power-law was reduced. The flow resistance coefficient was effectively reduced with the flow velocity increasing, the power-law fluid concentrations reducing and the element aspect ratio reducing. The study about flow characteristics of a power-law fluid in Kenics static mixer provided the basic data for optimizing structure design.

Performance analysis of the granular bed/cyclone coupled separator under different operation modes

Ming CHANG Jinzhuang FU Yongqi LI Yiping FAN Chunxi LU

The Chinese Journal of Process Engineering. 2022, 22(5):  631-639.  DOI: 10.12034/j.issn.1009-606X.221166

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A significant proportion of the dust in industrial flue gas is melted particles and these particles can cause problems such as blockages, wear, and corrosion in heat exchangers. Therefore, these melted dust particles must be removed before heat recycling. A separator coupling the cyclone with the built-in granular bed filter has been put forward. By investigating the influences of the full bed/empty bed operation on the coupled separator, the pressure drop and the collection efficiency were obtained under two different operations, respectively. Comparative experiments were carried out in a pilot-scale cold-model experimental apparatus. The inlet dust concentrations varied from 5.95 g/m3 to 59.13 g/m3 and the inlet velocity varied from 9.06 m/s to 13.59 m/s, respectively. The experimental results indicated that the collection efficiency under the full bed condition was higher than that under the empty bed condition. While the entrainment effect on the trapped dusts and the collector particles was enhanced by high inlet gas velocity, the collection efficiency of the built-in granular bed filter was increased. Besides, the pressure drop was much lower under the full bed operation. As the downward movement of the collector particles, the dust cake formed on the inner screen surface was continuous rubbed so that the cake thickness was retrained. Based on the particle size analysis, the collection efficiency of the dusts below 5 μm was improved due to the built-in granular bed filled with the collector particles. It was evident that the collection efficiency was further improved by combining different separation mechanisms in the cyclone. According to parameter, i.e., the quality factor, the coupled separator with the collector particles was verified to have a better comprehensive performance both on the collection efficiency and the pressure drop. In general, the collection efficiency and the stability were strengthened by the introduction of the built-in granular bed filter in the coupled separator. In addition, these self-cleaning phenomenons should be investigated in the future.

Co-pyrolysis characteristics of caking coal with non-caking coal

Fujun LI Zhouen LIU Shiqiu GAO Xin JIN Yimin XIE Zhipeng HE

The Chinese Journal of Process Engineering. 2022, 22(5):  640-650.  DOI: 10.12034/j.issn.1009-606X.221084

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The decaking technology with co-pyrolysis of caking coal and non-caking coal was brought out to destroy the caking property of caking coal. And the properties of decaking and co-pyrolysis of caking coal with the decaking technology were studied with co-pyrolysis experiments using TG-MS and fixed bed pyrolyzer. It could be seen from TG-MS experiments that the caking property of the mixed coal produced by caking coal and non-caking coal was smaller than that of caking coal. And pyrolysis of caking coal can be improved by the addition of non-caking coal. The co-pyrolysis characteristics of the mixed coal were the combined action of those of the two single coals. And it could be seen from the fixed-bed pyrolysis experiment that the decline of caking property of the mixed coal rised with smaller particle size of coal and the descent of the ratio of caking coal to non-caking coal in the mixed coal (XX:XF). And the agglomerate was slight. With the descent of XX:XF, the content of char reduced in pyrolysis products, but the contents of tar, coal gas and carbon deposition and water were higher. With the descent of XX:XF, the fractions of distillation cut <170℃ and 230~300℃ in tar from mixed coal first rise and then decrease and reach peak value at XX:XF=6:4~3:7, and the fractions of distillation cut of 170~210℃, 210~230℃, 300~360℃ rised, while the fraction of distillation cut >360℃ decreased. With the descent of XX:XF, the contents of H2, CO and CO2 in coal gas from mixed coal become larger, but the contents of CH4 and C2~C3 became smaller. While the contents of H2+CO+CH4 became first smaller and then larger with XX:XF and reached peak value at XX:XF=5:5~3:7. And with the descent of XX:XF, the char from mixed coal had smaller C/N and C/H, larger amplitudes of increase of C content and reduction of content of N and H, larger special surface area, more and larger internal pore structure, lower ignition temperature, more complete combustion.

A novel process for preparation Ti-rich material from modified electric furnace titanium slag by phase deconstruction method

Yusheng ZHOU Guanzhou QIU Jianfa JING Fuqiang ZHENG Shuai WANG Feng CHEN Yufeng GUO

The Chinese Journal of Process Engineering. 2022, 22(5):  651-659.  DOI: 10.12034/j.issn.1009-606X.221137

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In this study, a novel process for preparation rich-titanium material from modified titanium slag after melting in electric furnace by ammonium hydrogen fluoride leaching and hydrochloric acid leaching was proposed. The thermodynamic analysis of ammonium hydrogen fluoride leaching and hydrochloric acid leaching were investigated. The thermodynamic results of ammonium hydrogen fluoride leaching indicated that a small part of anosovite and the silicate can be decomposed, the silicate react with ammonium hydrogen fluoride leaching to produce sediment (CaMg2Al2F12), CaF2 and AlF3. The element of Si was converted to (NH4)2SiF6 existed in solution. The effects of ammonium hydrogen fluoride leaching conditions on the impurities extraction rate were investigated. The results indicated that the extraction rate of Si, Al, Ti, Fe, Ca and Mg were 93.55wt%, 28.03wt%, 3.88wt%, 20.50wt%, 3.40wt% and 2.45wt% respectively when the concentration of ammonium hydrogen fluoride was 15wt%, the liquid-solid ratio was 10:1, the temperature was 20℃ and the time was 2 h. The XRD results showed that the main phases in residue were rutile, anosovite and sediment (CaMg2Al2F12), the diopside was decomposed by ammonium hydrogen fluoride leaching. The thermodynamic results of hydrochloric acid leaching indicated that the sediment (CaMg2Al2F12), CaF2, AlF3 and the residual anovosite was decomposed by hydrochloric acid leaching. The effects of hydrochloric acid leaching conditions on the impurities extraction rate were investigated. The results of hydrochloric acid leaching indicated that the extraction rate of Ca, Al, Mg, Ti, Si and Fe were 86.78wt%, 62.33wt%, 92.31wt%, 18.08wt%, 40.23wt% and 75.36wt% respectively when the concentration of hydrochloric acid was 20wt%, the liquid-solid ratio was 8:1, the temperature was 120℃ and the time was 2 h. The main phase after hydrochloric acid leaching was rutile. The XRD results indicated that the sediment (CaMg2Al2F12) phase was solute by hydrochloric acid leaching. The titanium dioxide grade in rich-titanium material was 95.20wt%, the content of CaO was 0.49wt%, and the content of MgO was 0.48wt% which meet the need of boiling chlorination charge.

The influence mechanism of hydroxyl modification on the toluene adsorption by activated carbon based on molecular dynamics simulation

Bang XIAO Qing CAO Peiyong MA Hailin BI Pengcheng LI

The Chinese Journal of Process Engineering. 2022, 22(5):  660-670.  DOI: 10.12034/j.issn.1009-606X.221125

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In this work, activated carbon models modified with different hydroxy contents were constructed by implanting hydroxyl groups at the edges of coronene. The physical properties, atomic partial charges and pore size distribution of the modified activated carbon model were studied by molecular dynamics and giant canonical Monte Carlo simulation, and the kinetic characteristics and adsorption mechanism of toluene in modified activated carbon were further analyzed. The results showed that the introduction of hydroxyl can improve the adsorption capacity of activated carbon to toluene, and hydroxyl content significantly affected the adsorption capacity. At high relative pressure, the best concentration of the hydroxyl group was 39.4%, and when hydroxyl concentration exceeded this value, the adsorption amount of toluene decreased. The strong electronegative oxygen atom in the hydroxyl group of modified activated carbon and the hydrogen atom in the methyl of toluene were combined to form a Lewis acid-base pair, which led to a stable adsorption structure and then increased the adsorption capacity of activated carbon to toluene. At low relative pressure, the main factors affecting the adsorption capacity were porosity and pore size. The modified activated carbon with hydroxyl content of 20.8% and 31.4% had massive micropores and a relatively compact structure, which was favorable for toluene adsorption. The self-diffusion coefficient of the toluene molecule in activated carbon was decreased by hydroxyl modification, and the diffusion coefficient was the lowest in activated carbon containing 39.4% hydroxyl. This was because the non-bond interaction between the toluene molecule and modified activated carbon hindered the movement of the toluene molecule. In addition, according to the variable-temperature adsorption research, the increase in temperature was not conducive to the adsorption of toluene by activated carbon since it was an exothermic process. This study can provide a theoretical basis for the improvement of the adsorption performance of activated carbon materials.

Application of lignin epoxy resin synthesized in aqueous phase in wood adhesive

Yong WANG Yaqing YIN Qingyun LI Aixing TANG Lei ZHAO Youyan LIU

The Chinese Journal of Process Engineering. 2022, 22(5):  671-679.  DOI: 10.12034/j.issn.1009-606X.221198

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In this study, a lignin epoxy resin suitable for wood adhesive was synthesized in an aqueous phase by using lignin as raw material. To study the effect of reaction conditions of lignin epoxidation on the hydroxyl and epoxy groups of lignin-epoxy resin and the bonding strength of plywood, the structure of lignin-epoxy resin was characterized by FT-IR and 31P NMR, and the thermal stability of lignin-epoxy resin was analyzed by TG and DTG. The results showed that the epoxidation reaction mainly took place in the phenolic hydroxyl group. And in the process of epoxidation, the additional amount of NaOH exerted a greater effect on the structure of lignin epoxy resin and the bonding strength of plywood than that of epichlorohydrin. With the increase in the amount of NaOH added in the reaction process, the number of epoxy groups in lignin epoxy resin increased gradually and the bonding strength of plywood showed a trend of increasing firstly and then decreasing. When the molar ratio of a hydroxyl group to NaOH of lignin was 1:1, the bonding strength of plywood made of lignin epoxy resin can reach the maximum, and the wet strength can reach 1.61 MPa, which exceeded the requirements of class II board in Chinese national standard (≥0.7 MPa). SEM was used to study the bonding mechanism, it was found that the structure of cured lignin epoxy resin was more stable and compact when the degree of epoxidation was increased, which led to the improvement of the bonding strength of plywood. However, an excessively high degree of epoxidation will increase the particle size of the adhesive particles, resulting in the inability of the adhesive to form a good mechanical interlocking structure with the wood, thereby reducing the bonding strength of the plywood. Furthermore, the synthesis process of lignin epoxy resin wood adhesive was simplified, the epoxidized system can be directly applied to the wood adhesive, and after 30 days of storage, the bond strength did not decrease significantly. Besides, compared with commercial UF resin wood adhesive, the bonding strength of UF resin can reach the level of commercial UF resin. The results showed that this method may have a great application prospect in the wood adhesive industry.

Kinetics analysis of pyrolysis of waste epoxy printed circuit boards by non-isothermal method

Guizhen DING Liugen ZHENG Dun WU Wenfei CHI

The Chinese Journal of Process Engineering. 2022, 22(5):  680-688.  DOI: 10.12034/j.issn.1009-606X.221119

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The pyrolysis characteristics and pyrolysis mechanism of waste epoxy resin circuit boards containing a small amount of copper foil are mostly studied by a single "model matching method". To illustrate its pyrolysis catalysis, the pyrolysis characteristics and pyrolysis mechanism of the screened samples were analyzed by synchronous thermal analyzer and gas chromatography-mass spectrometry (GC-MS) at four different heating rates (5, 10, 15, 20℃/min), proposed a method to accurately calculate the "kinetic triplet". That is, firstly, two equal conversion methods were compared and analyzed to determine whether to follow a single pyrolysis reaction. Secondly, ?atava-?esták method and master curve method were used to select the appropriate mechanism model. Finally, the exact dynamic reaction order and mechanism function were obtained. The results showed that with the increase of heating rate, the residual residue in pyrolysis of waste circuit boards increased, indicating that the smaller the heating rate, the more complete the pyrolysis and the maximum rate of pyrolysis increased with the increase of heating rate. The pyrolysis process can be divided into four stages: the first stage (<150℃), evaporation of residual water on the surface or dissipation of other small molecules, the second stage (150~380℃), the third stage (380~500℃), the epoxy resin continued to decompose tetrabromobisphenol A, which formed small molecules and volatilized, and the fourth stage (>500℃), the pyrolysis residue decomposed slowly. Kissinger, Flynn-Wall-Ozawa and Friedman methods were used to solve the kinetic parameters of the thermal decomposition reaction of the sample, and finally the pre-exponential factor was 1.14×1022 min-1 and the activation energy was 218.533 kJ/mol. The mechanism function was compared and analyzed by ?atava-?esták method and master curve method, and finally the complete kinetic three factors were obtained. In addition, the relationship between activation energy and conversion rate proved that the waste epoxy resin circuit board can be modeled by Avrami-Erofeev equation (random nucleation and growth model) with reaction order of 5.4131: G(α)=[-ln(1-α)]5.4131.

Research on recovery process and kinetics of gallium and indium from MOCVD production waste

Fu RAO Xiaohong ZHENG Xihua ZHANG Tianyi TAO Hongbin CAO Weiguang LÜ Zhi SUN

The Chinese Journal of Process Engineering. 2022, 22(5):  689-698.  DOI: 10.12034/j.issn.1009-606X.221085

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In recent years, LED has been widely used in various lighting fields because of its energy-saving and environment-friendly characteristics. As a key part of LED products, epitaxial wafers are produced by metal-organic vapor deposition (MOCVD). With the rapid development of the LED industry, green and clean recycling of MOCVD production waste has attracted much attention. In this study, the leaching behavior and kinetics of Ga and In elements from MOCVD production waste were studied with sulfuric acid as a leaching agent. The effects of different types of leaching agents, H2SO4 concentration, solid-liquid ratio, leaching temperature and leaching time on the leaching efficiencies of Ga and In were systemically investigated. It was found that the leaching efficiencies of Ga and In can reach 67.50% and 91.46% under the optimal conditions of H2SO4 concentration of 3 mol/L, the solid-liquid ratio of 50 g/L, the temperature of 80℃, and the reaction of 120 min. The kinetics study showed that the leaching kinetics of Ga and In in the temperature range of 293.15~333.15 K was by the shrinkage core model, and the leaching process was controlled by surface chemical reaction and external diffusion mixing. At the same time, the results of XRD and SEM-EDS also confirmed the agreement with the shrinkage kernel model. The activation energies of Ga and In are 25.7 and 21.7 kJ/mol, respectively, when the leaching temperature was ranged from 293.15 K to 333.15 K. Based on the kinetics behavior of Ga and In leaching, the feasibility of enhanced roasting-acid leaching process was proposed and verified. It was found that the leaching efficiencies of Ga and In can be increased from 67.50% and 91.46% to 88.27% and 98.32%, respectively, under the enhanced roasting-acid leaching process. And gallium oxide byproducts were obtained. The findings from this research are expected to provide technical support and alternative for industrial recycling of critical metals from MOCVD production waste.