scholarly journals Selective Extraction of Ni from Superalloy Scraps by Molten Mg-Zn

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 993
Author(s):  
Qinghua Tian ◽  
Xiangdong Gan ◽  
Fuhui Cui ◽  
Dawei Yu ◽  
Xueyi Guo
Keyword(s):  
Vacuum Distillation ◽  
Heating Temperature ◽  
Selective Extraction ◽  
Heating Time ◽  
Metal Extraction ◽  
Molar Ratio ◽  
Distillation Process ◽  
Mass Ratio ◽  
Critical Metals ◽  
Nickel Based Superalloy

Bearing significant concentrations of high value and critical metals, superalloy scraps require comprehensive recycling for metal reclamation. In this study, nickel-based superalloy was treated with molten Mg-Zn for the selective extraction of nickel. The influence of heating temperature, the molar ratio of Mg to Zn in the molten metal, Mg-Zn/superalloy mass ratio, and heating time on metal extraction were investigated. Using the heating temperature of 800 °C, the Mg/Zn molar ratio of 9/1, the Mg-Zn/superalloy mass ratio of 5/1, and heating time of 240 min, the extraction rate of 97.1% was achieved for Ni, and the extraction rates of Fe, Cr and refractory metals (Nb, Mo and Ti) were all less than 1%. In the subsequent vacuum distillation process, nickel with a purity of 98.3 wt% was obtained. Therefore, the proposed method is a short, clean, and efficient process for selectively extracting nickel from the superalloy scraps.

Ammonium removal from wastewater via struvite pyrolysate recycling with Mg(OH)2 addition

2013 ◽  
Vol 68 (12) ◽  
pp. 2661-2667 ◽  
Author(s):  
Rongtai Yu ◽  
Subin Cheng ◽  
Hongqiang Ren ◽  
Yanru Wang ◽  
Lili Ding ◽  
...  
Keyword(s):  
Heating Temperature ◽  
Ammonium Phosphate ◽  
Heating Time ◽  
Phosphate Concentration ◽  
Molar Ratio ◽  
Optimum Conditions ◽  
Magnesium Ammonium Phosphate ◽  
Ammonium Removal ◽  
Ammonia Release ◽  
Magnesium Ammonium

Magnesium ammonium phosphate (MAP) pyrolysate recycling technology was investigated with Mg(OH)2-mediated pyrolysis. The results revealed that the removal ratio of ammonium was stable at about 75%, and could be increased to 79% after additional acidolysis. The phosphate concentration in the supernate was low at 2 mg/L. The optimum conditions for ammonia release were a 1:1 molar ratio of Mg(OH)2:NH4+, a heating temperature of 110 °C and a heating time of 3 h. With continual additions of Mg(OH)2 to release ammonia, magnesium phosphate (Mg3(PO4)2) was suggested as a possible derivative. However, with Mg(OH)2-mediated pyrolysis, the growth and nucleation of MAP was inhibited during MAP pyrolysate recycling.

scholarly journals Study on Ultra-High Temperature Contact Solution Treatment of Al–Zn–Mg–Cu Alloys

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 842
Author(s):  
Wenming Jin ◽  
Jianhao Yu ◽  
Zhiqiang Zhang ◽  
Hongjie Jia ◽  
Mingwen Ren
Keyword(s):  
Heating Temperature ◽  
Solution Treatment ◽  
Strengthening Mechanism ◽  
Heating Time ◽  
Solution Time ◽  
Solution Temperature ◽  
Second Phase ◽  
Total Strength ◽  
Cu Alloys ◽  
Short Heating Time

Contact solution treatment (CST) of Al–Zn–Mg–Cu alloys can shorten solution time to within 40 s in comparison with 1800 s with traditional solution treatment using a heating furnace. Heating temperature is the key factor in solution treatment. Considering the short heating time of CST, the ultra-high solution temperature over 500 °C of Al–Zn–Mg–Cu alloys was studied in this work. The effects of solution temperatures on the microstructures and the mechanical properties were investigated. The evolution of the second phases was explored and the strengthening mechanisms were also quantitatively evaluated. The results showed that solution time could be reduced to 10 s with the solution temperature of 535 °C due to the increasing dissolution rate of the second phase and the tensile strength of the aged specimen could reach 545 MPa. Precipitation strengthening was the main strengthening mechanism, accounting for 75.4% of the total strength. Over-burning of grain boundaries occurred when the solution temperature increased to 555 °C, leading to the deterioration of the strength.

scholarly journals Continuous Integrated Process of Biodiesel Production and Purification—The End of the Conventional Two-Stage Batch Process?

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 403
Author(s):  
Matea Bačić ◽  
Anabela Ljubić ◽  
Martin Gojun ◽  
Anita Šalić ◽  
Ana Jurinjak Tušek ◽  
...  
Keyword(s):  
Extraction Efficiency ◽  
Deep Eutectic Solvent ◽  
International Standards ◽  
Biodiesel Production ◽  
Molar Ratio ◽  
Process Conditions ◽  
Integrated Process ◽  
Free Glycerol ◽  
Mass Ratio ◽  
Glycerol Content

In this research, optimization of the integrated biodiesel production process composed of transesterification of edible sunflower oil, catalyzed by commercial lipase, with simultaneous extraction of glycerol from the reaction mixture was performed. Deep eutectic solvents (DESs) were used in this integrated process as the reaction and extraction media. For two systems, choline chloride:glycerol (ChCl:Gly) and choline chloride:ethylene glycol (ChCl:EG), respectively, the optimal water content, mass ratio of the phase containing the mixture of reactants (oil and methanol) with an enzyme and a DES phase (mass ratio of phases), and the molar ratio of deep eutectic solvent constituents were determined using response surface methodology (RSM). Experiments performed with ChCl:Gly resulted in a higher biodiesel yield and higher glycerol extraction efficiency, namely, a mass ratio of phases of 1:1, a mass fraction of water of 6.6%, and a molar ratio of the ChCl:Gly of 1:3.5 were determined to be the optimal process conditions. When the reaction was performed in a batch reactor under the optimal conditions, the process resulted in a 43.54 ± 0.2% yield and 99.54 ± 0.19% glycerol extraction efficiency (t = 2 h). Unfortunately, the free glycerol content was higher than the one defined by international standards (wG > 0.02%); therefore, the process was performed in a microsystem to enhance the mass transfer. Gaining the same yield and free glycerol content below the standards (wG = 0.0019 ± 0.003%), the microsystem proved to be a good direction for future process optimization.

Numerical Simulation and Process Optimization of Automotive Friction Materials in Warm Pressing Forming

2013 ◽  
Vol 788 ◽  
pp. 57-60
Author(s):  
Chun Cao ◽  
Chun Dong Zhu ◽  
Chen Fu
Keyword(s):  
Process Optimization ◽  
Heating Temperature ◽  
Maximum Energy ◽  
Heating Time ◽  
Product Performance ◽  
Forming Process ◽  
Friction Materials ◽  
Forming Technology ◽  
The Relationship ◽  
Temperature Heating

Warm pressing forming technology has been gradually applied to the forming of automotive friction materials. How to ensure product performance to achieve the target at the same time achieve the maximum energy saving is the research focus of this study. In this paper, by using finite element method, the field of automotive friction materials in warm pressing forming was analyzed, reveals the relationship between the temperature field and the heating temperature/heating time. Furthermore, the energy consumption was analyzed and compared it with hot pressing forming process. The results will have significant guiding to the process optimization in warm pressing forming.

Application Self-Regulating Heating Cable Curing of Concrete in Winter

2014 ◽  
Vol 638-640 ◽  
pp. 1531-1535 ◽  
Author(s):  
Jin Bao Guo ◽  
Lin Liu ◽  
Qiang Wang
Keyword(s):  
Heat Dissipation ◽  
Heating Temperature ◽  
Heating Time ◽  
Minimum Length ◽  
It Use ◽  
Heating Efficiency ◽  
Cable Length ◽  
Heating Cable ◽  
Curing Methods ◽  
Two Parameters

In order to solve the shortcomings of traditional methods of concrete curing in winter, proposed self-regulating heating cable new concrete curing methods. Several aspects were considered, about the heating cable length and heating time, heating temperature. According to energy conservation, heating and heat dissipation balance, derived formulas of heating cable normal use length and minimum. As conclusions is shown, first, the normal length design can controlled better heating temperature, it use the cable length and heating time, heating temperature two parameters to control the other parameters. Second, it is better heating efficiency, can be the overall warming state quickly. In addition, when the concrete pouring temperature is above 10 °C, it is not need additional heating, and it can choose minimum length design formula.

Resistance Welding Process Development and Optimization for Recycled High-Density Polyethylene (HDPE)

2015 ◽  
Author(s):  
Peter F. Baumann ◽  
Lucas Sendrowski
Keyword(s):  
Tensile Strength ◽  
Response Surface ◽  
High Density Polyethylene ◽  
Heating Temperature ◽  
Base Material ◽  
Heating Time ◽  
High Density ◽  
Hot Plate ◽  
Initial Testing ◽  
Hot Plate Welding

Large recycled high-density polyethylene (HDPE) structural members, difficult to manufacture by extrusion processes, have been created by the hot plate welding of simple plastic lumber sections. Hot plate welding generates better joint strength than any other welding method currently employed in plastic manufacturing. However, to achieve the desired temperature of the thick plate to melt the polymer uniformly, the process needs a high amount of heat energy requiring furnace (or resistance) heating of a considerable mass. A new method which could combine the heating element and a thin plate into one source could be more efficient in terms of heat loss and thus energy used. The premise of this investigation is to replace the hot plate with a very thin piece of high resistance nickel-chromium alloy ribbon to localize the application of heat within a plastic weld joint in order to reduce energy loss and its associated costs. This resistance ribbon method uses electrical current to reach an adequate temperature to allow for the welding of the HDPE plastic. The ribbon is only slightly larger than the welding surface and very thin to reduce the loss of excess heat through unused surface area and thick sides. The purpose of this project was to weld recycled high-density polyethylene (HDPE) using resistance welding and to match the tensile strength results considered acceptable in industry for hot plate welding, that is, equal to or greater than 80% of the base material strength. Information obtained through literature review and previous investigations in our laboratories established welding (heating) temperature and time as testing factors. Designed experimentation considered these factors in optimizing the process to maximize the weld tensile strength. A wide-ranging full-factorial experimental design using many levels was created for the initial testing plan. Tensile strengths obtained after welding under the various condition combinations of weld temperature and time revealed a region of higher strength values in the response surface. After the wide-range initial testing, the two control parameters, heating temperature and heating time, were ultimately set up in a focused Face Centered Cubic (FCC) Response Surface Method (RSM) testing design and the tensile strength response was then analyzed using statistical software. The results obtained indicated a strong correlation between heating time and heating temperature with strength. All welded samples in the final testing set exhibited tensile strength of over 90% base material, meeting the goal requirements. A full quadratic equation relationship for tensile strength as a function of welding time and temperature was developed and the maximum tensile strength was achieved when using 280°C for 60 seconds.

Extent of damage to amino acid availability of whey protein heated with sugar

1991 ◽  
Vol 58 (4) ◽  
pp. 431-441 ◽  
Author(s):  
Thérèse Desrosiers ◽  
Laurent Savoie
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Whey Protein ◽  
Significant Proportion ◽  
Protein Digestibility ◽  
Heating Time ◽  
Heat Treatments ◽  
Molar Ratio ◽  
Amino Acid Availability

SummaryThe effect of heat treatments, at various water activities (αw), on digestibility and on the availabilities of amino acids of whey protein samples in the presence of lactose was estimated by an in vitro digestion method with continuons dialysis. Four αw (0·3, 0·5, 0·7 and 0·97), three temperatures (75, 100 and 121 °C) and three heating periods (50, 500 and 5000 s) were selected. The initial lysine: lactose molar ratio was 1:1. Amino acid profiles showed that excessive heating of whey (121 °C, 5000 s) destroyed a significant proportion of cystine at all αw, lysine at αw 0·3, 0·5 and 0·7, and arginine at αw 0·5 and 0·7. At αw 0·3, 0·5 and 0·7, protein digestibility decreased (P < 0·05) as the temperature increased from 75 to 121 °C for a heating period of 5000 s, and as the heating time was prolonged from 500 to 5000 s at 121 °C. Excessive heating also decreased (P < 0·05) the availabilities of ail amino acids at αw 0·3, 0·5 and 0·7. The availabilities of lysine, proline, aspartic acid, glutamic acid, threonine, alanine, glycine and serine were particularly affected. Severe heating at αw 0·97 did not seem to favour the Maillard reaction, but the availabilities of cystine, tyrosine and arginine were decreased, probably as a result of structural modifications of the protein upon heating. Heating whey protein concentrates in the presence of lactose not only affected lysine, but also impaired enzymic liberation of other amino acids, according to the severity of heat treatments and αw.

Synthesis of AM-co-NVP and Thermal Stability in Hostile Saline Solution

2012 ◽  
Vol 602-604 ◽  
pp. 1349-1354 ◽  
Author(s):  
Rui Liu ◽  
Wan Fen Pu ◽  
Qin Peng ◽  
Feng Sheng Yao
Keyword(s):  
Thermal Stability ◽  
Saline Solution ◽  
Heat Stability ◽  
Structure Characterization ◽  
Vinyl Pyrrolidone ◽  
Molar Ratio ◽  
Mass Ratio ◽  
Excellent Thermal Stability ◽  
Hydrolyzed Polyacrylamide ◽  
Feed Molar Ratio

copolymer preparation; structure characterization; thermal stability; brines solution. Abstract. The copolymer (AM-co-NVP) of acrylamide (AM) and vinyl pyrrolidone (NVP) was carried out in the presence of 2,2'-azobis[2-methylpropionamidine] dihydrochloride（V50）as initiator by free radical polymerization. The copolymer was characterized by its chemical structure with Fourier transform infrared spectroscopy (FTIR). The heat resistance of AM-co-NVP at 100°C and 120°C in harsh saline solution with high mineralized concentration ranging from 5×104 mg/L to 20×104 mg/L containing 2.5% (mass ratio) CaCl2, 2.5% (mass ratio) MgCl2 and 95% NaCl (mass ratio) was investigated. The experimental results indicate that AM-co-NVP has excellent thermal stability in saline solution compared to partially hydrolyzed polyacrylamide (HPAM). What is more, the copolymer exhibited the most perfect thermal tolerance in high divalent saline solution when the feed molar ratio of AM and NVP is 91.5 to 8.5. The microstructures of the copolymer samples after thermal aging in hostile environment captured by scanning electron microscope (SEM）further proved the NVP monomer was effectively introduced leading to the copolymer favorable heat stability in particularly high mineralized solution.

scholarly journals Biodiesel Production from Castor Oil and Its Application in Diesel Engine

2014 ◽  
Vol 31 (2) ◽  
pp. 90 ◽  
Author(s):  
S Ismail ◽  
S. A Abu ◽  
R Rezaur ◽  
H Sinin
Keyword(s):  
Diesel Engine ◽  
Castor Oil ◽  
Engine Performance ◽  
Calorific Value ◽  
Biodiesel Production ◽  
Molar Ratio ◽  
Mass Ratio ◽  
Performance And Emission ◽  
Transesterification Method ◽  
Optimum Production

In this study, the optimum biodiesel conversion from crude castor oil to castor biodiesel (CB) through transesterification method was investigated. The base catalyzed transesterification under different reactant proportion such as the molar ratio of alcohol to oil and mass ratio of catalyst to oil was studied for optimum production of castor biodiesel. The optimum condition for base catalyzed transesterification of castor oil was determined to be 1:4.5 of oil to methanol ratio and 0.005:1 of potassium hydroxide to oil ratio. The fuel properties of the produced CB such as the calorific value, flash point and density were analyzed and compared to conventional diesel. Diesel engine performance and emission test on different CB blends proved that CB was suitable to be used as diesel blends. CB was also proved to have lower emission compared to conventional diesel.

scholarly journals SPECTROPHOTOMETRIC DETERMINATION OF PYROCATHECOL AND PYROGALLOL BASED ON THEIR REDOX REACTION WITH IRON(III)/PHENANTHROLINE SYSTEM

2010 ◽  
Vol 2 (3) ◽  
pp. 161-166 ◽  
Author(s):  
Mudasir Mudasir ◽  
Mugiyanti Mugiyanti ◽  
Ngatidjo Hadipranoto
Keyword(s):  
Phenolic Compounds ◽  
Redox Reaction ◽  
Heating Temperature ◽  
Heating Time ◽  
Maximum Absorption ◽  
Optimum Conditions ◽  
Phenanthroline Complex ◽  
Maximum Absorption Wavelength ◽  
Absorption Wavelength

An analytical method for the spectrophotometric determination of some phenolic compounds, i.e.: pyrocathecol and pyrogallol based on their redox reaction with iron(III)-phenanthroline complex has been developed. These two compounds, in appropriate conditions, reduce iron(III)-phenanthroline complex to yield very stable and color-intense complex of iron(II)-phenanthroline, [Fe(phen)2]2+, whose concentration is equivalent to the amount of pyrocathecol or pyrogallol in the solution, and is easily detected by spectrophotometric method. Some parameters influencing the sensitivity of the determination were optimized. These included maximum absorption wavelength, pH of the solution, time and temperature of heatingand reagent to analyte minimum mole-ratio. Using the optimum conditions obtained, the analytical performance of the method was examined and the developed method was then applied to analyzed pyrocathecol and pyrogallol contents in several river water of Yogyakarta, Indonesia. Result of the study showed that the optimum conditions for the determination of pyrocathecol are as follows: maximum absorption wavelength (lmax) at 510 nm, pH of the solution = 4, heating time = 120 min, heating temperature = 70 0C and the minimum mole ratio of reagent to analyte is 8. On the other hand, the optimum conditions for the determination of pyrogallol are as follows: maximum absorption wavelength (lmax) at 510 nm, pH of the solution = 5, heating time = 90 min, heating temperature = 90 0C and the minimum mole ratio of reagent to analyte is 7. At the corresponding conditions of analysis, calibration curves for pyrocathecol and pyrogallol are linear in the range concentration of 0.00 - 0.16 ppm and 0.00 - 0.24 ppm, respectively. The correlation coefficients for both compounds were found to be higher than 0.998 and the detection limits went down below 0.07 ppm. It has been demonstrated that the developed method can be applied for the determination of pyrocathecol and pyrogallol contents in natural samples.   Keywords: Spectrophotometry, phenolic compounds, 1,10-phenanthroline, redox reaction

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