Leaching kinetics of electronic waste for the recovery of copper: Rate‐controlling step and rate process in a multisize particle system

2020 ◽  
Author(s):  
Gloria I. Dávila‐Pulido ◽  
Armando Salinas‐Rodríguez ◽  
Francisco R. Carrillo‐Pedroza ◽  
Adrián A. González‐Ibarra ◽  
Juan Méndez‐Nonell ◽  
...  
Keyword(s):  
Particle System ◽  
Electronic Waste ◽  
Leaching Kinetics ◽  
Rate Process ◽  
Kinetics Of ◽  
Rate Controlling Step

Study on leaching kinetics of hexavalent chromium from aged calcium-free chromium slag

2021 ◽  
pp. 1-13
Author(s):  
Quan Qi ◽  
Liang Li ◽  
Liangyu Wei ◽  
Baoming Hu ◽  
Zheng Liu ◽  
...  
Keyword(s):  
Hexavalent Chromium ◽  
Resource Utilization ◽  
Scientific Basis ◽  
Diffusion Reaction ◽  
Leaching Kinetics ◽  
Leaching Rate ◽  
Chromium Slag ◽  
Leaching Solution ◽  
Main Components ◽  
Kinetics Of

To provide a scientific basis for the resource utilization of chromium slag, this article studies the release law of hexavalent chromium in the aged calcium-free chromium slag. XRD (X-ray diffractometer) and MLA (Mineral Liberation Analyzer) were used to analyze the composition of the chromium slag; using sulfuric acid-nitric acid as the leaching solution, the release law of hexavalent chromium in chromium slag and the leaching kinetics were studied. The results show that main components of the chromium slag are magnesioferrite, chromite, hematite, hydrargillite, and spinel; chromium is mainly present in chromite and magnesioferrite; the leaching rate of hexavalent chromium increases with the increase of temperature or the decrease of pH. The analysis of leaching kinetics shows the leaching rate is controlled by the internal diffusion reaction, and the apparent activation energy is 11.93 kJ·mol–1. The chromium slag is aged in high temperature seasons, which is conducive to the precipitation of hexavalent chromium in the chromium slag, can increase the yield of chromate in the roasting kiln, and is conducive to resource utilization; chromium slag should be stored in order to prevent acid rain erosion which leads to environmental pollution risk (e.g. drinking water).

Leaching kinetics of copper and valuable metal extraction from copper-cadmium residues of zinc hydrometallurgy by oxidation acid leaching

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Jihao Guo ◽  
Hongao Xu ◽  
Bo Li ◽  
Yonggang Wei ◽  
Hua Wang
Keyword(s):  
Hydrogen Peroxide ◽  
Acid Concentration ◽  
Acid Leaching ◽  
Metal Extraction ◽  
Agitation Rate ◽  
Leaching Kinetics ◽  
Solid Ratio ◽  
Zinc Hydrometallurgy ◽  
Kinetics Of ◽  
Leaching Efficiency

Abstract Multiple purification of zinc sulfate solution is an important process for zinc hydrometallurgy, and large quantities of copper-cadmium residues are generated as byproducts in this process. Copper-cadmium residues contain a large number of valuable metals that must be recovered. A comprehensive extraction process has been proposed using sulfuric acid as the leaching reagent and hydrogen peroxide as the oxidizing reagent. The effects of acid concentration, leaching temperature, leaching time, liquid-to-solid ratio, hydrogen peroxide dosage and stirring speed on the leaching efficiency were investigated. The optimum conditions were determined as an acid concentration of 150 g/L, liquid-to-solid ratio of 4:1, hydrogen peroxide amount of 20 mL, time of 60 min, temperature of 30 °C, particle size of −d75 μm, and agitation rate of 300 r/min. It was concluded that the leaching efficiency of copper and cadmium reached 97%, but because of the existence of zinc sulfide in the residues, a lower leaching efficiency of zinc was obtained. Furthermore, the leaching kinetics of copper was also studied based on the shrinking core model. The activation energy for copper leaching was 5.06 kJ/mol, and the leaching process was controlled by the diffusion through the product layer.

Leaching kinetics of colemanite in potassium hydrogen sulphate solutions

2012 ◽  
Vol 18 (1) ◽  
pp. 38-44 ◽  
Author(s):  
Rövşen Guliyev ◽  
Soner Kuşlu ◽  
Turan Çalban ◽  
Sabri Çolak
Keyword(s):  
Leaching Kinetics ◽  
Potassium Hydrogen ◽  
Hydrogen Sulphate ◽  
Kinetics Of

scholarly journals Comparing hydrogen absorption kinetics of the samples of intermetallic compound and metal hydride compact on its basis

2021 ◽  
Vol 2057 (1) ◽  
pp. 012043
Author(s):  
I A Romanov ◽  
V I Borzenko ◽  
A N Kazakov
Keyword(s):  
Intermetallic Compound ◽  
Metal Hydride ◽  
Hydrogen Absorption ◽  
Reaction Rate ◽  
Nickel Foam ◽  
High Confidence ◽  
Compact Sample ◽  
Kinetics Of ◽  
Rate Controlling Step ◽  
Absorption Of Hydrogen

Abstract This work is devoted to an experimental study and comparison of the kinetics of hydrogen absorption by an intermetallic compound LaNi4.4Al0.3Fe0.3 in form of pure intermetallic compound free backfill and a compact based on it obtained by cold pressing with a spiral matrix of nickel-foam. To calculate the kinetic parameters of the hydrogen absorption reaction, the initial rates method is used. The PCT absorption isotherms are measured at temperatures of 313, 333, and 353 K. The experimental data are described with quite high confidence by the chosen model, which assumes that the reaction rate controlling step is the dissociative absorption of hydrogen on the surface of the a-phase. The rate of hydrogen absorption increases with increasing pressure drop and temperature. It is shown that the rate of hydrogen absorption by the sample of pure IMC is significantly less dependent on temperature compared to the compact sample. In addition, the reaction rate at temperatures of 313 and 333 K is higher for the free backfill sample, and at 353 K it is higher for the metal hydride compact. The values of the absorption constant and the activation energy of the hydrogen absorption reaction are determined for both samples.

Leaching kinetics of szaibelyite ore in NaOH solution

2015 ◽  
Vol 157 ◽  
pp. 333-339 ◽  
Author(s):  
Shiyue Qin ◽  
Baowen Yin ◽  
Yifei Zhang ◽  
Yi Zhang
Keyword(s):  
Leaching Kinetics ◽  
Naoh Solution ◽  
Kinetics Of

Effect of mechanical activation on the leaching kinetics of niobium-bearing mineralisation in KOH hydrothermal system

2018 ◽  
Vol 181 ◽  
pp. 123-129 ◽  
Author(s):  
Xiaohui Wang ◽  
Yujuan Jia ◽  
Shuhua Ma ◽  
Shili Zheng ◽  
Qing Sun
Keyword(s):  
Mechanical Activation ◽  
Hydrothermal System ◽  
Leaching Kinetics ◽  
Kinetics Of

Alkaline Hydrothermal Treatment and Leaching Kinetics of Silicon from Laterite Nickel Ore

2021 ◽  
Author(s):  
Shiyuan Cao ◽  
Longjiao Chang ◽  
Xiaolong Bi ◽  
Shaohua Luo ◽  
Jianan Liu
Keyword(s):  
Hydrothermal Treatment ◽  
Leaching Kinetics ◽  
Kinetics Of
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