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Green process to recover magnesium chloride from residue solution of potassium chloride production plant

WANG Lin, HE Yunliang, WANG Yanfei, BAO Ying, WANG Jingkang

《化学科学与工程前沿(英文)》 2008年 第2卷 第4期   页码 385-389 doi: 10.1007/s11705-008-0079-z

摘要: The green process to recover magnesium chloride from the residue solution of a potassium chloride production plant, which comes from the leach solution of a potash mine in Laos, is designed and optimized. The residue solution contains magnesium chloride above 25 wt-%, potassium chloride and sodium chloride together below 5 wt-% and a few other ions such as Br, SO and Ca. The recovery process contains two steps: the previous impurity removal operation and the two-stage evaporation-cooling crystallization procedure to produce magnesium chloride. The crystallized impurity carnallite obtained from the first step is recycled to the potassium chloride plant to recover the potassium salt. The developed process is a zero discharge one and thus fulfills the requirements for green chemical industrial production. The produced magnesium chloride is up to industrial criteria.

关键词: industrial production     chemical industrial     produced magnesium     chloride production     impurity carnallite    

Influences of additives on the crystal habit of potassium chloride

Xiaofu GUO, Junsheng YUAN, Zhiyong JI, Min SU,

《化学科学与工程前沿(英文)》 2010年 第4卷 第1期   页码 78-81 doi: 10.1007/s11705-009-0300-8

摘要: By means of constant control speed cooling crystallization, the influences of four additives, including lead chloride, cadmium chloride, sodium salicylate, and quaternary ammonium salt, on the crystal habit of KCl were investigated. The results show that the crystal habit of KCl is cube without additives, the crystal habit of KCl is ellipsoid-like in the presence of Pb, the crystal habit of KCl is strip in the presence of Cd, and the crystal habit of KCl is cavate cube in the presence of sodium salicylate. X-ray diffractometry analysis reveals that these additives can change the crystal habit of KCl but not its crystal structure.

关键词: cadmium chloride     salicylate     presence     crystallization     diffractometry analysis    

Chemical deactivation of V

Xiaodong WU, Wenchao YU, Zhichun SI, Duan WENG

《环境科学与工程前沿(英文)》 2013年 第7卷 第3期   页码 420-427 doi: 10.1007/s11783-013-0489-0

摘要: V O -WO /TiO catalyst was poisoned by impregnation with NH Cl, KOH and KCl solution, respectively. The catalysts were characterized by X-ray diffraction (XRD), inductively coupled plasma (ICP), N physisorption, Raman, UV-vis, NH adsorption, temperature-programmed reduction of hydrogen (H -TPR), temperature-programmed oxidation of ammonia (NH -TPO) and selective catalytic reduction of NO with ammonia (NH -SCR). The deactivation effects of poisoning agents follow the sequence of KCl>KOH>>NH Cl. The addition of ammonia chloride enlarges the pore size of the titania support, and promotes the formation of highly dispersed V=O vanadyl which improves the oxidation of ammonia and the high-temperature SCR activity. K ions are suggested to interact with vanadium and tungsten species chemically, resulting in a poor redox property of catalyst. More importantly, potassium can reduce the Br?nsted acidity of catalysts and decrease the stability of Br?nsted acid sites significantly. The more severe deactivation of the KCl-treated catalyst can be mainly ascribed to the higher amount of potassium resided on catalyst.

关键词: V2O5-WO3/TiO2     potassium chloride     poisoning     reducibility     acid sites    

Effect of potassium carbonate on catalytic synthesis of calcium carbide at moderate temperature

Dejun SHI, Ke QIAO, Zifeng YAN

《化学科学与工程前沿(英文)》 2011年 第5卷 第3期   页码 372-375 doi: 10.1007/s11705-010-0570-1

摘要: Calcium carbide was successfully synthesized by carbothermal reduction of lime with coke at 1973 K for 1.5 h. The effect of potassium carbonate as additive on the composition and morphology of the product was investigated using X-ray diffraction and scanning electron microscope. Addition of potassium carbonate increased the yield of calcium carbide. The sample in the presence of potassium carbonate generated acetylene gas of 168.3 L/kg, which was 10% higher than that in the absence of potassium carbonate. This result confirmed the catalytic effect of potassium carbonate on the synthesis of calcium carbide. A possible mechanism of the above effects was that the additive, which was melted at the reduction temperature, dissolved CaO and so promoted the contact between CaO and carbon, which was essential for the solid-solid reaction to form calcium carbide.

关键词: calcium carbide     synthesis     catalysis    

Insight of chemical environmental risk and its management from the vinyl chloride accident

《环境科学与工程前沿(英文)》 2023年 第17卷 第4期 doi: 10.1007/s11783-023-1652-x

摘要: The combustion of vinyl chloride (VC) after the train derailment accident in Ohio, USA in February, 2023 has caused widespread concern around the world. This paper tried to analyze several issues concerning the accident, including the appropriateness of the VC combustion in the emergency response in this accident, the meanings of so-called “controlled combustion”, the potential environmental risks caused by VC and combustion by-products, and follow-up work. In our view, this accident had surely caused environmental and health risks to some extent. Hence, a comprehensive environmental risk assessment is necessary, and then the site with risk should be comprehensively remediated, hazardous waste should be harmlessly treated as soon as possible. Finally, this accident suggests that further efforts should be taken to bridge the gap between chemical safety management and their environmental risk management.

关键词: Vinyl chloride     Combustion     Chemical safety management     Environmental risk     Emerging contaminants    

Evaluating effect of chloride attack and concrete cover on the probability of corrosion

Sanjeev Kumar VERMA, Sudhir Singh BHADAURIA, Saleem AKHTAR

《结构与土木工程前沿(英文)》 2013年 第7卷 第4期   页码 379-390 doi: 10.1007/s11709-013-0223-9

摘要: Corrosion of reinforced concrete (RC) structures is one of the significant causes of deterioration of reinforced concrete (RC) structures. Chlorination is a major process governing the initiation and advancement of the injurious corrosion of steel bars. Now, several researches on the chlorination of concrete structures have been ongoing around the world. Present article reviews several recently performed chlorination studies, and from results of a field survey evaluates the effect of chloride content on the probability of corrosion and the influence of concrete compressive strength on the chloride content and penetration, also evaluates the effect of concrete cover over the chloride content of the RC structures at rebar depth and on the probability of corrosion.

关键词: concrete     chloride     reinforcement     corrosion     deterioration     cover    

Progress on cleaner production of vinyl chloride monomers over non-mercury catalysts

Jinli ZHANG, Nan LIU, Wei LI, Bin DAI

《化学科学与工程前沿(英文)》 2011年 第5卷 第4期   页码 514-520 doi: 10.1007/s11705-011-1114-z

摘要: Polyvinyl chloride (PVC) has become the third most used plastic after polyethylene and polypropylene and the worldwide demand continues to increase. Polyvinyl chloride is produced by polymerization of the vinyl chloride monomer (VCM), which is manufactured industrially via the dehydrochlorination of dichloroethane or the hydrochlorination of acetylene. Currently PVC production through the acetylene hydrochlorination method accounts for about 70% of the total PVC production capacity in China. However, the industrial production of VCM utilizes a mercuric chloride catalyst to promote the reaction of acetylene and hydrogen chloride. During the hydrochlorination, the highly toxic mercuric chloride tends to sublime, resulting in the deactivation of the catalyst and also in severe environmental pollution problems. Hence, for China, it is necessary to explore environmental friendly non-mercury catalysts for acetylene hydrochlorination as well as high efficiency novel reactors, with the aim of sustainable PVC production via the acetylene-based method. This paper presents a review of non-mercury heterogeneous and homogeneous catalysts as well as reactor designs, and recommends future work for developing cleaner processes to produce VCM over non-mercury catalysts with high activity and long stability.

关键词: polyvinyl chloride     vinyl chloride monomer     acetylene hydrochlorination     non-mercury catalysts     green chemical process    

Chloride binding and time-dependent surface chloride content models for fly ash concrete

S. MUTHULINGAM,B. N. RAO

《结构与土木工程前沿(英文)》 2016年 第10卷 第1期   页码 112-120 doi: 10.1007/s11709-015-0322-x

摘要: Corrosion of embedded rebars is a classical deterioration mechanism of reinforced concrete structures exposed to chloride environments. Such environments can be attributed to the presence of seawater, deicing or sea-salts, which have high concentrations of chloride ion. Chloride ingress into concrete, essential for inducing rebar corrosion, is a complex interaction between many physical and chemical processes. The current study proposes two chloride ingress parameter models for fly ash concrete, namely: 1) surface chloride content under tidal exposure condition; and 2) chloride binding. First, inconsistencies in surface chloride content and chloride binding models reported in literature, due to them not being in line with past research studies, are pointed out. Secondly, to avoid such inconsistencies, surface chloride content and chloride binding models for fly ash concrete are proposed based upon the experimental work done by other researchers. It is observed that, proposed models are simple, consistent and in line with past research studies reported in literature.

关键词: binding isotherms     chloride ingress     concrete     fly ash     surface chloride content    

Experimental study on high-efficiency polishing for potassium dihydrogen phosphate (KDP) crystal by using

Ziyuan LIU, Hang GAO, Dongming GUO

《机械工程前沿(英文)》 2020年 第15卷 第2期   页码 294-302 doi: 10.1007/s11465-019-0576-4

摘要: A high-efficiency polishing approach using two-phase air–water fluid (TAWF) is proposed to avoid surface contamination and solve the inefficiency of previous water-dissolution polishing techniques for potassium dihydrogen phosphate (KDP) crystal. In the proposed method, controllable deliquescence is implemented without any chemical impurity. The product of deliquescence is then removed by a polishing pad to achieve surface planarization. The mechanism underlying TAWF polishing is analyzed, a special device is built to polish the KDP crystal, and the effect of relative humidity (RH) on polishing performance is studied. The relationship between key parameters of polishing and surface planarization is also investigated. Results show that the polishing performance is improved with increasing RH. However, precisely controlling the RH is extremely difficult during TAWF polishing. Controllable deliquescence can easily be disrupted once the RH fluctuates, which therefore needs to be restricted to a low level to avoid its influence on deliquescence rate. The material removal of TAWF polishing is mainly attributed to the synergistic effect of deliquescence and the polishing pad. Excessive polishing pressure and revolution rate remarkably reduce the life of the polishing pad and the surface quality of the KDP crystal. TAWF polishing using IC-1000 and TEC-168S increase the machining efficiency by 150%, and a smooth surface with a root mean square surface roughness of 5.5 nm is obtained.

关键词: potassium dihydrogen phosphate (KDP) crystal     controllable deliquescence     two-phase air–water fluid     high-efficiency polishing     material removal    

On corrosion to stainless steel by calcium chloride with different extender

Lv XU, Yuanyang HU, Liwei WANG, Ruzhu WANG,

《能源前沿(英文)》 2010年 第4卷 第2期   页码 181-184 doi: 10.1007/s11708-009-0065-2

摘要: A calcium chloride solution with a different extender, which is made up of either pure calcium chloride, calcium chloride with expanded graphite, or calcium chloride with activated carbon, acts differently on stainless steel. The mass ratio between calcium chloride with expanded graphite or activated carbon is almost 4∶1, which is demonstrated to be the optimum ratio. The experimental research in this paper reveals that, of the three solutions, which are pure calcium chloride, calcium chloride with expanded graphite, and calcium chloride with activated carbon, the strongest oxidation creation and pitting corrosion happened in the solution of calcium chloride with expanded graphite, the weakest oxidation creation happened in the solution of calcium chloride with activated carbon, and pitting corrosion was stronger than oxidation creation in the solution of pure calcium chloride. This paper gives the reasons for these phenomena. Furthermore, based on theory analysis, multiple means and approaches are provided to prevent stainless steel from further corroding.

关键词: stainless steel     corrosion     calcium chloride     expanded graphite     activated carbon     oxidation creation     pitting corrosion    

A space power system of free piston Stirling generator based on potassium heat pipe

Mingqiang LIN, Jian MOU, Chunyun CHI, Guotong HONG, Panhe GE, Gu HU

《能源前沿(英文)》 2020年 第14卷 第1期   页码 1-10 doi: 10.1007/s11708-019-0655-6

摘要: The power system of a free piston Stirling generator (FPSG) based on potassium heat pipes has been developed in this paper. Thanks to the advantages of long life, high reliability, and high overall thermal efficiency, the FPSG is a promising candidate for nuclear energy, especially in space exploration. In this paper, the recent progress of FPSG based on nuclear reactor for space use was briefly reviewed. A novel FPSG weighted only 4.2 kg was designed, and one dimensional thermodynamic modeling of the FPSG using Sage software was performed to estimate its performance. The experiment results indicated that this FPSG could provide 142.4 W at a thermal-to-electric efficiency of nearly 17.4%. Besides, the power system integrated with four FPSGs and potassium heat pipes was performed and the single machine failure test was conducted. The results show that this system could provide an electrical power of 300 W at an overall thermal efficiency of 7.3%. Thus, it is concluded that this power system is feasible and will have a great prospect for future applications.

关键词: free piston Stirling generator (FPSG)     potassium heat pipe     power system     energy conversion    

Effect of adding a smart potassium ion-responsive copolymer into polysulfone support membrane on the

Meibo He, Zhuang Liu, Tong Li, Chen Chen, Baicang Liu, John C. Crittenden

《化学科学与工程前沿(英文)》 2019年 第13卷 第2期   页码 400-414 doi: 10.1007/s11705-018-1757-0

摘要: Thin-film composite (TFC) nanofiltration (NF) membranes were fabricated via the interfacial polymerization of piperazine (PIP) and 1,3,5-benzenetricarbonyl trichloride on polysulfone (PSf) support membranes blended with K -responsive poly( -isopropylacryamide-co-acryloylamidobenzo-15-crown-5) (P(NIPAM-co-AAB C )). Membranes were characterized by attenuated total reflection Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, atomic force microscope, scanning electron microscope, contact angle, and filtration tests. The results showed that: (1) Under K -free conditions, the blended P(NIPAM-co-AAB C )/PSf supports had porous and hydrophilic surfaces, thereby producing NF membranes with smooth surfaces and low MgSO rejections; (2) With K in the PIP solution, the surface roughness and water permeability of the resultant NF membrane were increased due to the K -induced transition of low-content P(NIPAM-co-AAB C ) from hydrophilic to hydrophobic; (3) After a curing treatment at 95 °C, the improved NF membrane achieved an even higher pure water permeability of 10.97 L·m ·h ·bar under 200 psi. Overall, this study provides a novel method to improve the performance of NF membranes and helps understand the influence of supports on TFC membranes.

关键词: nanofiltration     interfacial polymerization     support membrane     potassium ion-responsive     thin-film composite    

Coupled diffusion of chloride and other ions in saturated concrete

Nattapong DAMRONGWIRIYANUPAP, Linyuan LI, Yunping XI

《结构与土木工程前沿(英文)》 2011年 第5卷 第3期   页码 267-277 doi: 10.1007/s11709-011-0112-z

摘要: Corrosion of reinforcing steel due to chloride ions is one of the severe deterioration problems in long-term performance of reinforced concrete structures. The deterioration process is frequently found in marine concrete structures, highway pavements, and bridges exposed to deicing salts. The diffusion of chloride ions is associated and strongly affected by other ions in the pore solution in concrete. In this paper, chloride penetration into concrete structures was mathematically characterized by the Nernst-Planck equation which considered not only diffusion mechanism of the chloride ions but also ionic interaction among other ions coming from externally applied deicers and within the Portland cement paste. Electroneutrality was used to determine the electrostatic potential induced by the ionic interaction. The material models of chloride binding capacity and chloride diffusion coefficient were incorporated in the governing equations. The governing equations were solved by using finite element method. A numerical example was used to illustrate the coupling effect of multi-ionic interactions and the effect of influential parameters. The numerical results obtained from the present model agreed very well with available test data.

关键词: diffusion     chloride     concrete     Nernst-Planck equation     durability    

Long-term durability of onshore coated concrete —chloride ion and carbonation effects

Seyedhamed SADATI,Mehdi K. MORADLLO,Mohammad SHEKARCHI

《结构与土木工程前沿(英文)》 2016年 第10卷 第2期   页码 150-161 doi: 10.1007/s11709-016-0341-2

摘要: Enhancing service life of reinforced concrete (RC) structures located in marine environments is an issue of great interest for design engineers. The present research addresses the effect of surface coatings on service life of onshore RC structures. Long-term performance of concrete samples up to 88 months of exposure at natural marine environment was investigated. Two onshore exposure conditions, including soil and atmosphere and different types of concrete coatings were studied. Carbonation rates of up to 0.5 and 1.5 mm/year were observed at the first 88 months of exposure for soil and atmospheric samples, respectively. Surface chloride ion build-up and variation in chloride ion diffusion were monitored with respect to time, and service life was estimated. Based on the obtained results it is proposed to use the aliphatic acrylic and polyurethane coatings for enhancing the service life of concrete structures in the investigated exposure conditions.

关键词: carbonation     chloride ion     corrosion     service life     surface coating    

Impacts of climate change on optimal mixture design of blended concrete considering carbonation and chloride

Xiao-Yong WANG

《结构与土木工程前沿(英文)》 2020年 第14卷 第2期   页码 473-486 doi: 10.1007/s11709-020-0608-5

摘要: Many studies on the mixture design of fly ash and slag ternary blended concrete have been conducted. However, these previous studies did not consider the effects of climate change, such as acceleration in the deterioration of durability, on mixture design. This study presents a procedure for the optimal mixture design of ternary blended concrete considering climate change and durability. First, the costs of CO emissions and material are calculated based on the concrete mixture and unit prices. Total cost is equal to the sum of material cost and CO emissions cost, and is set as the objective function of the optimization. Second, strength, slump, carbonation, and chloride ingress models are used to evaluate concrete properties. The effect of different climate change scenarios on carbonation and chloride ingress is considered. A genetic algorithm is used to find the optimal mixture considering various constraints. Third, illustrative examples are shown for mixture design of ternary blended concrete. The analysis results show that for ternary blended concrete exposed to an atmospheric environment, a rich mix is necessary to meet the challenge of climate change, and for ternary blended concrete exposed to a marine environment, the impact of climate change on mixture design is marginal.

关键词: ternary blended concrete     climate change     optimal mixture design     carbonation     chloride ingress    

标题 作者 时间 类型 操作

Green process to recover magnesium chloride from residue solution of potassium chloride production plant

WANG Lin, HE Yunliang, WANG Yanfei, BAO Ying, WANG Jingkang

期刊论文

Influences of additives on the crystal habit of potassium chloride

Xiaofu GUO, Junsheng YUAN, Zhiyong JI, Min SU,

期刊论文

Chemical deactivation of V

Xiaodong WU, Wenchao YU, Zhichun SI, Duan WENG

期刊论文

Effect of potassium carbonate on catalytic synthesis of calcium carbide at moderate temperature

Dejun SHI, Ke QIAO, Zifeng YAN

期刊论文

Insight of chemical environmental risk and its management from the vinyl chloride accident

期刊论文

Evaluating effect of chloride attack and concrete cover on the probability of corrosion

Sanjeev Kumar VERMA, Sudhir Singh BHADAURIA, Saleem AKHTAR

期刊论文

Progress on cleaner production of vinyl chloride monomers over non-mercury catalysts

Jinli ZHANG, Nan LIU, Wei LI, Bin DAI

期刊论文

Chloride binding and time-dependent surface chloride content models for fly ash concrete

S. MUTHULINGAM,B. N. RAO

期刊论文

Experimental study on high-efficiency polishing for potassium dihydrogen phosphate (KDP) crystal by using

Ziyuan LIU, Hang GAO, Dongming GUO

期刊论文

On corrosion to stainless steel by calcium chloride with different extender

Lv XU, Yuanyang HU, Liwei WANG, Ruzhu WANG,

期刊论文

A space power system of free piston Stirling generator based on potassium heat pipe

Mingqiang LIN, Jian MOU, Chunyun CHI, Guotong HONG, Panhe GE, Gu HU

期刊论文

Effect of adding a smart potassium ion-responsive copolymer into polysulfone support membrane on the

Meibo He, Zhuang Liu, Tong Li, Chen Chen, Baicang Liu, John C. Crittenden

期刊论文

Coupled diffusion of chloride and other ions in saturated concrete

Nattapong DAMRONGWIRIYANUPAP, Linyuan LI, Yunping XI

期刊论文

Long-term durability of onshore coated concrete —chloride ion and carbonation effects

Seyedhamed SADATI,Mehdi K. MORADLLO,Mohammad SHEKARCHI

期刊论文

Impacts of climate change on optimal mixture design of blended concrete considering carbonation and chloride

Xiao-Yong WANG

期刊论文