scholarly journals Recovery of Diamond and Cobalt Powders from Polycrystalline Drawing Die Blanks via Ultrasound Assisted Leaching Process—Part 2: Kinetics and Mechanisms

Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 741
Author(s):  
Ferdinand Kießling ◽  
Srecko Stopic ◽  
Sebahattin Gürmen ◽  
Bernd Friedrich
Keyword(s):  
Polycrystalline Diamond ◽  
Reaction Rate Constant ◽  
Free Gibbs Energy ◽  
Aqua Regia ◽  
Leaching Process ◽  
Drawing Die ◽  
Diffusion Controlled ◽  
Cobalt Removal ◽  
Shrinking Core ◽  
Solid Liquid

The leaching of industrial polycrystalline diamond (PCD) blanks in aqua regia at atmospheric pressure between 60 °C and 80 °C was performed using an ultrasound to improve the rate of cobalt removal in order to be able to reuse very expensive polycrystalline diamond. Because cobalt (20 wt.%) is used as a solvent catalyst in the production of PCD, its recovery is very important. The cleaned PCD are returned to the production process. Kinetic models were used in the study of cobalt dissolution from polycrystalline diamond blanks by measuring the declining ferromagnetic properties over time. For a better understanding of this leaching process, thermochemical aspects are included in this work. The lowest free Gibbs energy value was obtained with a low solid/liquid ratio and the full use of an ultrasound. A transition from a reaction-controlled to a diffusion-controlled shrinking core model was observed for PCD with a thickness greater than 2.8–3.4 mm. Intermittent ultrasound doubles the reaction rate constant, and the full use of ultrasound provides a 1.5-fold further increase. The obtained maximum activation energy between 60 °C and 80 °C is 20 kJ/mol, for a leaching of diamond blank with grain size of 5 µm.

Solid-Liquid Extraction Kinetics of Flavonoids in Ficus microcarpa

2011 ◽  
Vol 396-398 ◽  
pp. 575-581
Author(s):  
Li Sheng Wang ◽  
Li Heng Liu ◽  
Man Duan ◽  
Xiong Min Liu
Keyword(s):  
Liquid Extraction ◽  
Diffusion Control ◽  
Extraction Kinetics ◽  
Leaching Process ◽  
Shrinking Core ◽  
Higher Temperature ◽  
Ficus Microcarpa ◽  
Solid Liquid Extraction ◽  
Solid Liquid ◽  
Kinetics Of

The solid-liquid extraction kinetics of flavonoids from Ficus microcarpa with ethanol was studied. The effects of temperature and concentration of ethanol on extraction kinetics were examined. It is found that the higher temperature and concentration of ethanol, the higher leaching yields. The leaching process can be described by outer diffusion control model before 60 min and the shrinking-core model between 60 min and 150 min. The leaching process kinetics equations were established, respectively.

scholarly journals Recovery of Diamond and Cobalt Powder from Polycrystalline Drawing Die Blanks via Ultrasound-Assisted Leaching Process—Part 1: Process Design and Efficiencies

Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 731
Author(s):  
Ferdinand Kießling ◽  
Srecko Stopic ◽  
Sebahattin Gürmen ◽  
Bernd Friedrich
Keyword(s):  
Process Design ◽  
Negative Impact ◽  
Polycrystalline Diamond ◽  
Cobalt Content ◽  
Industrial Applications ◽  
Liquid Ratio ◽  
Leaching Process ◽  
Drawing Die ◽  
Ultrasound Assisted ◽  
Blank Size

The treatment of industrial polycrystalline diamond (PCD) blanks in aqua regia at atmospheric pressure between 333 K and 353 K was performed via the ultrasound-assisted leaching process to investigate whether the influence of ultrasound is beneficial. Cobalt content in the solution and in the blanks was monitored as well as the effects of leaching temperature, solid-to-liquid ratio, and PCD blank size. The use of intermittent and permanent ultrasound helped reduce the leaching time and thus energy consumption by up to 50%. In all trials with ultrasound, higher temperature only has a slight effect. Solid-to-liquid ratio does not have a positive or negative impact. A new process design was tested using an innovative experimental setup for ultrasound-assisted leaching aiming at maximum cobalt and diamond recovery from PCD and final reuse of fine PCD for cutting and polishing other hard materials in different important industrial applications.

KINETIC MODEL FOR IDENTIFYING THE RATE CONTROLLING STEP OF THE ALUMINUM LEACHING FROM PEAT CLAY

2018 ◽  
Vol 80 (2) ◽  
Author(s):  
Agus Mirwan ◽  
Susianto Susianto ◽  
Ali Altway ◽  
Renanto Handogo
Keyword(s):  
Chemical Reaction ◽  
Product Layer ◽  
Rate Equations ◽  
Stage Model ◽  
Surface Chemical ◽  
Surface Chemical Reaction ◽  
Leaching Process ◽  
Shrinking Core ◽  
Solid Liquid ◽  
Rate Controlling Step

The aluminum (Al) leaching kinetics from peat clay was investigated using various acid concentrations 1 M to 6 M, particle sizes +70-120 mesh to +200-325 mesh and temperatures 30 °C to 90 °C. They all have significant effects on aluminum leaching process. The Al leaching recovery was best found to be 91.3 % at 4 M hydrochloric acid (HCl), using a particle size of +200-325 mesh with solid/liquid of 0.02 g·ml-1. Leaching kinetic study was applied to the two rate equations proposed that is acid diffusion via product layer and surface chemical reaction using the shrinking core (SC) model to analyze the leaching data. The product layer diffusion is controlling Al leaching process for one-stage model, while for two-stage model, it was controlled by surface chemical reaction. The activation energy in the two rate controlling step was 82.79 kJ mol-1 and 27.08 kJ mol-1, respectively. 

scholarly journals Study on Ultrasonically-Enhanced Sulfuric Acid Leaching of Nickel from Nickel-Containing Residue

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 810
Author(s):  
Zhanyong Guo ◽  
Ping Guo ◽  
Guang Su ◽  
Fachuang Li
Keyword(s):  
Sulfuric Acid ◽  
Acid Leaching ◽  
Ultrasonic Waves ◽  
Sulfuric Acid Leaching ◽  
Solid Product ◽  
Leaching Process ◽  
Diffusion Controlled ◽  
Extraction Degree ◽  
Ultrasonic Conditions ◽  
Complex Nickel

In this paper, nickel-containing residue, a typical solid waste produced in the battery production process, was used to study the cavitation characteristics of ultrasonic waves in a liquid–solid reaction. The ultrasonically-enhanced leaching technology for multicomponent and complex nickel-containing residue was studied through systematic ultrasonic-conventional comparative experiments. An ultrasonic leaching kinetics model was established which provided reliable technological guidance and basic theory for the comprehensive utilization of nickel-containing residue. In the study, it was found that ultrasonically-enhanced leaching for 40 min obtained the same result as conventional leaching for 80 min, and the Ni extraction degree reached more than 95%. According to the kinetic fitting of the leaching process, it was found that the sulfuric acid leaching process belonged to the diffusion-controlled model of solid product layers under conventional and ultrasonic conditions, and the activation energy of the reaction was Ea1 = 17.74 kJ/mol and Ea2 = 5.04 kJ/mol, respectively.

scholarly journals Fundamental Study of Palladium Recycling Using “Dry Aqua Regia” Considering the Recovery from Spent Auto-catalyst

2021 ◽  
Author(s):  
Akihiro Yoshimura ◽  
Shunta Tochigi ◽  
Yasunari Matsuno
Keyword(s):  
Potassium Chloride ◽  
Platinum Group Metals ◽  
Recycling Process ◽  
Fundamental Study ◽  
Aqua Regia ◽  
Sodium Chloride Solutions ◽  
Pure Compounds ◽  
The Difference ◽  
Solid Liquid ◽  
Solid Liquid Separation

AbstractIn this research, a recycling process for palladium using “dry aqua regia,” which consists of iron(III) chloride–potassium chloride, was proposed. Palladium was dissolved in “dry aqua regia,” and the dissolved palladium was recovered by leaching with potassium chloride solution with added ammonium chloride and nitric acid. Palladium was almost completely dissolved in 3 h at 600 K, and the recovery ratio of dissolved palladium was up to 80%. In addition, the dissolution of palladium in coexistence with platinum and the dissolution of platinum-palladium alloy by “dry aqua regia” were also tested. The dissolved palladium and platinum were separated and recovered by solid–liquid separation technique using the difference in solubility of their compounds in potassium chloride and sodium chloride solutions. As a result, pure compounds of each element were recovered. This result suggested the possibility of using “dry aqua regia” for the separation of platinum-group metals. Graphical Abstract

Intensification of solid–liquid separation by thermal sedimentation in pressure oxidative leaching process of chromite

2021 ◽  
Vol 164 ◽  
pp. 106825
Author(s):  
Xiaoyu Tang ◽  
Shihao He ◽  
Facheng Qiu ◽  
Xianfeng Qin ◽  
Xuejun Quan ◽  
...  
Keyword(s):  
Liquid Separation ◽  
Leaching Process ◽  
Oxidative Leaching ◽  
Solid Liquid ◽  
Solid Liquid Separation

scholarly journals Kinetic Study in Atmospheric Pressure Organic Acid Leaching: Shrinking Core Model versus Lump Model

Minerals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 613
Author(s):  
Kevin Cleary Wanta ◽  
Widi Astuti ◽  
Indra Perdana ◽  
Himawan Tri Bayu Murti Petrus
Keyword(s):  
Citric Acid ◽  
Acid Solution ◽  
Acid Leaching ◽  
Core Model ◽  
Shrinking Core Model ◽  
Citric Acid Solution ◽  
Lumped Model ◽  
Leaching Process ◽  
Shrinking Core ◽  
Simulation Results

The kinetics study has an essential role in the scale-up process because it illustrates the real phenomena of a process. This study aims to develop a mathematical model that can explain the mechanism of the leaching process of laterite ore using a low concentration of the citric acid solution and evaluate that model using the experimental data. As a raw material, this process used powder-shaped limonite laterite ores with a size of 125–150 µm. The leaching process is carried out using 0.1 M citric acid solution, F:S ratio of 1:20, and a leaching time of 2 h. The temperature parameter was varied at 303, 333, and 358 K. The experimental results showed that the higher the operating temperature, the higher the extracted nickel. The results of this experiment were used to evaluate the shrinking core kinetics model and the lumped model. The simulation results for both models show that the lumped model can provide better simulation results. Quantitatively, the percentage of errors from the shrinking core model is around 3.5 times greater than the percentage of errors from using the lumped model. This result shows that in this leaching process, the process mechanism that occurs involves the reactant diffusion step and the chemical reactions step; those steps run simultaneously.

scholarly journals Bacterial leaching kinetics for copper dissolution from a lowgrade Indian chalcopyrite ore

2013 ◽  
Vol 66 (2) ◽  
pp. 245-250 ◽  
Author(s):  
Abhilash ◽  
K.D. Mehta ◽  
B.D. Pandey
Keyword(s):  
Phase Identification ◽  
Low Grade ◽  
Bacterial Leaching ◽  
Copper Dissolution ◽  
Diffusion Controlled ◽  
Shrinking Core ◽  
Copper Mines ◽  
Chalcopyrite Ore ◽  
Best Fit

Bio-leaching of copper (0.3%) from a low grade Indian chalcopyrite ore of Malanjkhand copper mines, using a native mesophilic isolate predominantly Acidithiobacillus ferrooxidans (A.ferrooxidans), is reported. A bio-recovery of 72% Cu was recorded in the presence of this culture (not adapted), which increased to 75% with an ore adapted culture after 35 days at 35ºC and pH 2.0 with <50fim particles. The kinetic data showed best fit for the diffusion-controlled shrinking core model, exhibiting linear plots for [1- 2/3X-(1-X)2/3] vs time (X-fraction leached). Apparently, the role of the bacteria is to convert the ferrous ion to the ferric state, which oxidizes the chalcopyrite in order to dissolve copper, while maintaining a high redox potential. The activation energy value (E) was calculated to be 96 and 108 kJ/mol for the un-adapted culture and the ore adapted culture respectively in the temperature range 25-35ºC. This leaching mechanism was corroborated by XRD phase identification and SEM studies of the leach residue.

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