Anomalous behaviours of protactinium in the acid-leaching experiments on pitchblende

1985 ◽  
Vol 92 (2) ◽  
pp. 315-321 ◽  
Author(s):  
Z. Z. Sheng ◽  
P. K. Kuroda
Keyword(s):  
Acid Leaching ◽  
Leaching Experiments

scholarly journals Recovery of Zinc and Silver from Zinc Acid-Leaching Residues with Reduction of Their Environmental Impact Using a Novel Water Leaching-Flotation Process

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 586
Author(s):  
Yunpeng Du ◽  
Xiong Tong ◽  
Xian Xie ◽  
Wenjie Zhang ◽  
Hanxu Yang ◽  
...  
Keyword(s):  
Hazardous Waste ◽  
Acid Leaching ◽  
Copper Recovery ◽  
Water Leaching ◽  
Flotation Process ◽  
Metal Levels ◽  
Valuable Metals ◽  
Leaching Experiments ◽  
Zinc Hydrometallurgy ◽  
Poor Stability

Zinc-leaching residue (ZLR) is a strongly acidic hazardous waste; it has poor stability, high heavy metal levels, and releases toxic elements into the environment. ZLR has potential as a valuable resource, because it contains elevated levels of zinc and silver. In this paper, the recovery of zinc (Zn) and silver (Ag) from ZLR wastes from zinc hydrometallurgy workshops using water leaching followed by flotation was studied. During water leaching experiments, the zinc and copper recovery rates were 38% and 61%, respectively. Thereafter, various flotation testing parameters were optimized and included grinding time, reagent dosages, pulp density, flotation time, and type of adjuster. Experimental results demonstrated this flotation method successfully recycled Ag and Zn. A froth product containing more than 9256.41 g/t Ag and 12.26% Zn was produced from the ZLR with approximately 80.32% Ag and 42.88% Zn recoveries. The toxicity characteristic leaching procedure (TCLP) results indicated the water-leaching flotation process not only recycled valuable metals such as zinc and silver in zinc-containing hazardous wastes but lowered the hazardous waste levels to those of general wastes and recycled wastes in an efficient, economical, and environmentally friendly way.

scholarly journals The Alteration Mechanism of Copper-bearing Biotite and Leachable Property of Copper-bearing Minerals in Mulyashy Copper Mine, Zambia

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Gai-rong Wang ◽  
Hong-ying Yang ◽  
Yuan-yuan Liu ◽  
Lin-lin Tong ◽  
Ali Auwalu
Keyword(s):  
Sample Size ◽  
Acid Leaching ◽  
Special Structure ◽  
Leaching Rate ◽  
Polarizing Microscopy ◽  
Copper Mine ◽  
Copper Leaching ◽  
Different Temperatures ◽  
Leaching Experiments

Abstract The XRF, XRD, polarizing microscopy and SEM-EDS were used to study the alteration mechanism of copper-bearing biotite and the leachable property of copper-bearing minerals in Mulyashy Copper Mine, Zambia. It was found that biotite can be divided into copper-bearing biotite and copper-free biotite. Some copper-bearing biotite existed in the form of monomer, and others aggregated with copper-bearing chlorite, malachite or copper-bearing limonite. The main reason for the occurrence of biotite aggregations was that copper-bearing biotite underwent two kinds of alteration mechanisms as follows: altering into copper-bearing chlorite and malachite, and altering into copper-bearing chlorite and copper-bearing limonite. The order of factors effecting the copper leaching rate of the ores in acid leaching experiments was temperature > sample size > H2SO4 concentration > leaching time > stirring speed. In addition, the copper leaching rate of copper-bearing minerals at different temperatures was in the following order: malachite, chrysocolla and pseudomalachite > copper-bearing chlorite > copper-bearing muscovite > copper-bearing biotite > copper-bearing limonite. The leachable property of biotite is closely related to its special structure.

scholarly journals A New Process of Extracting Titanium from Vanadium–Titanium Magnetite

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 327
Author(s):  
Yandong Li ◽  
Shuangyin Chen ◽  
Huamei Duan
Keyword(s):  
Recovery Rate ◽  
Acid Leaching ◽  
Leaching Rate ◽  
Optimum Conditions ◽  
Solid Ratio ◽  
New Process ◽  
Leaching Experiments ◽  
Panxi Area ◽  
Vanadium Titanium ◽  
Titanium Magnetite

A new process of extracting titanium from vanadium–titanium magnetite (VTM) in the Panxi area in Sichuan, China is introduced in this work. Various experiments, including reduction–magnetic separation, leaching and hydrolyzing experiments, are carried out. The results show that the optimum conditions for leaching experiments are an acid/slag ratio of 4:1, a leaching temperature of 60 °C, a leaching time of 80 min, and a liquid/solid ratio of 3.2:1. The leaching rate of titanium in Ti-bearing slag is 92.41%. The optimum conditions for hydrolyzing experiments are an H+ concentration of 0.75 g·L−1, hydrolyzing temperature of 100 °C, and hydrolyzing time of 180 min, and the hydrolyzing rate of titanium in acid leaching liquor is 96.80%. After the leaching and hydrolyzing experiments, the recovery rate of titanium from the Ti-bearing slag is 89.45%.

Acid Leaching of Cu and Zn from a Smelter Slag with a Bacterial Consortium

2015 ◽  
Vol 1130 ◽  
pp. 660-663 ◽  
Author(s):  
Olli H. Tuovinen ◽  
Silja Särkijärvi ◽  
Esa Peuraniemi ◽  
Saku Junnikkala ◽  
Jaakko A. Puhakka ◽  
...  
Keyword(s):  
Slag Sample ◽  
Acid Leaching ◽  
Bacterial Consortium ◽  
Growth Media ◽  
Dissolved Metals ◽  
Test Culture ◽  
Shake Flasks ◽  
Leaching Experiments ◽  
Cu And Zn ◽  
Smelter Slag

This study was undertaken to determine the leaching of Cu and Zn from a smelter slag in acidic, sulfate-rich solutions with, and without, mesophilic Fe-and S-oxidizing bacteria. Cu in the slag was mostly distributed in fayalite, Fe-deficient Cu-sulfides and metallic Cu, and Zn was associated with fayalite, magnetite and glassy silicates. The test culture was enriched from acid mine water using mineral salt growth media supplemented with 4.5 g Fe2+ L-1 and 10 g S0 L-1. The bioleaching experiments were carried out in shake flasks at 27 °C and chemical controls were included. The slag sample was pre-leached for 24 h to partially satisfy the acid demand before the leaching experiments at 10% pulp density. In the bioleaching experiments, 69-83% Cu and 4.1-14% Zn were dissolved in 25 days at pH 2.0-2.2. The highest extent of bioleaching was with S0 as the substrate. The efficiency of the bioleaching depended on H2SO4 generation from the added S0. The activities of the bacteria were not adversely affected by the dissolved metals. The maximum yields of chemical leaching were 68% Cu and 3.7% Zn.

Excess argon in amphiboles linked to greenschist facies alteration in the Kamila Amphibolite Belt, Kohistan island arc system, northern Pakistan: insights from 40Ar/39Ar step-heating and acid leaching experiments

1996 ◽  
Vol 133 (5) ◽  
pp. 595-609 ◽  
Author(s):  
Jo Anne Wartho ◽  
David C. Rex ◽  
Philip G. Guise
Keyword(s):  
Shear Zone ◽  
Acid Leaching ◽  
Northern Region ◽  
Greenschist Facies ◽  
Acid Etching ◽  
Northern Pakistan ◽  
Brittle Deformation ◽  
Excess Argon ◽  
Step Heating ◽  
Leaching Experiments

AbstractA mineralogical and 4OAr/39Ar study of 13 amphibole samples in the Kamila Amphibolite Belt and Kamila Shear Zone in northern Pakistan has found a correlation between the degree of greenschist facies alteration and quantity of excess 40Ar. Additionally, there is a north–south divide with amphibole samples from the northern region showing larger degrees of gree schist facies alteration, brittle deformation, and excess 40Ar incorporation compared to the predominantly plastically deformed, less altered, amphibole samples from the Kamila Shear Zone in the south. Acid leaching of two amphiboles from the Kamila Amphibolite Belt indicates that a large proportion of the excess 40Ar is correlated with later greenschist facies alteration hases, and can be easily removed by acid etching, thus revealing acceptable regional 40Ar/39Ar plateau ages.

scholarly journals The Investigation of Optimizing Leaching Efficiency of Al in Secondary Aluminum Dross via Pretreatment Operations

Processes ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 1269
Author(s):  
Haigang Feng ◽  
Guofan Zhang ◽  
Qun Yang ◽  
Luobing Xun ◽  
Siyuan Zhen ◽  
...  
Keyword(s):  
Chemical Interaction ◽  
Acid Leaching ◽  
Scanning Electron Micrographs ◽  
Water Leaching ◽  
Secondary Aluminum ◽  
Aluminum Dross ◽  
Process Mineralogy ◽  
Leaching Experiments ◽  
Physical And Chemical ◽  
Leaching Efficiency

Secondary aluminum dross (SAD) is an inevitable by-product from the secondary aluminum industry and has caused serious environmental issues. In this study, the effect of pretreatment operations on the subsequent acid leaching operation was studied by process mineralogy, a series of leaching experiments, XRD, and SEM. Leaching results showed that the leaching efficiency of Al in direct acid leaching was only 22.99%. Process mineralogy showed the complex intertexture and continuous network structure in the SAD. Pretreatment operations were extremely efficient in destroying the structure by physical and chemical interaction. Interestingly, by adding the grinding and water leaching operations, the leaching efficiency of total aluminum in the SAD reached approximately 28.70%. XRD results showed that nearly all metallic Al, AlN, and partial Al2O3 were leached by grinding–water leaching–acid leaching. The scanning electron micrographs showed that the residue particles mainly included some insoluble components and had a smooth surface.

Accelerating Mineral Carbonation in Ultramafic Mine Tailings via Direct CO2 Reaction and Heap Leaching with Potential for Base Metal Enrichment and Recovery

2020 ◽  
Vol 115 (2) ◽  
pp. 303-323 ◽  
Author(s):  
Jessica L. Hamilton ◽  
Siobhan A. Wilson ◽  
Bree Morgan ◽  
Anna L. Harrison ◽  
Connor C. Turvey ◽  
...  
Keyword(s):  
Mine Tailings ◽  
Reactive Transport ◽  
Co2 Sequestration ◽  
Acid Leaching ◽  
Heap Leaching ◽  
Column Experiments ◽  
Mineral Carbonation ◽  
Field Scale ◽  
Ore Processing ◽  
Leaching Experiments

Abstract Accelerated carbonation of ultramafic mine tailings has the potential to offset CO2 emissions produced by mining ores from Cu-Ni-platinum group element, podiform chromite, diamondiferous kimberlite, and historical chrysotile deposits. Treatments such as acid leaching, reaction of tailings with elevated concentrations of gaseous CO2, and optimization of tailings pore water saturation have been shown to enhance CO2 sequestration rates in laboratory settings. The next challenge is to deploy treatment technologies on the pilot and field scale while minimizing cost, energy input, and adverse environmental impacts. Implementation of accelerated tailings carbonation at field scale will ideally make use of in situ treatments or modified ore-processing routes that employ conventional technology and expertise and operate at close to ambient temperatures and pressures. Here, we describe column experiments designed to trial two geochemical treatments that address these criteria: (1) direct reaction of partially saturated ultramafic tailings with synthetic flue gas from power generation (10% CO2 in N2) and (2) repeated heap leaching of ultramafic tailings with dilute sulfuric acid. In the first experiment, we report rapid carbonation of brucite [Mg(OH)2] in the presence of 10% CO2 gas within tailings sampled from the Woodsreef chrysotile mine, New South Wales, Australia. Within four weeks, we observe a doubling of the amount of CO2 stored within minerals relative to what is achieved after three decades of passive mineral carbonation via air capture in the field. Our simulated heap leaching experiments, treated daily with 0.08 M H2SO4, produce high-Mg leachates that have the potential to sequester 21.2 kg CO2 m–2 y–1, which is approximately one to two orders of magnitude higher than the rate of passive carbonation of the Woodsreef mine tailings. Although some nesquehonite (MgCO3 · 3H2O) forms from these leachates, most of the Mg is precipitated as Mg sulfate minerals instead. Therefore, an acid other than H2SO4 could be used; otherwise, sulfate removal would be required to maximize CO2 sequestration potential from acid heap leaching treatments. Reactive transport modeling (MIN3P) is employed to simulate acid leaching experiments and predict the effects of heap leaching for up to five years. Finally, our synchrotron X-ray fluorescence microscopy results for leached tailings material reveal that valuable trace metals (Fe, Ni, Mn, Co, Cr) become highly concentrated within secondary Fe (hydr)oxide minerals at the pH neutralization horizon within our column experiments. This discrete horizon migrates downward, and our reactive transport models indicate it will become increasingly enriched in first-row transition metals in response to continued acid leaching. Acid-leaching treatments for accelerated mineral carbonation could therefore be useful for ore processing and recovery of base metals from tailings, waste rock, or low-grade ores.

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