scholarly journals Dissolution of copper from smelting slag by leaching in chloride media

2017 ◽  
Vol 53 (3) ◽  
pp. 407-412
Author(s):  
M. Dimitrijevic ◽  
D. Urosevic ◽  
S. Milic ◽  
M. Sokic ◽  
R. Markovic
Keyword(s):  
Hydrogen Peroxide ◽  
Hydrochloric Acid ◽  
Aqueous Solutions ◽  
Room Temperature ◽  
Catalytic Decomposition ◽  
Copper Smelting ◽  
Copper Extraction ◽  
Complete Dissolution ◽  
Iron Extraction ◽  
Smelting Slag

Leaching of copper smelting slag in chloride media was studied. The lixiviants used were aqueous solutions of hydrochloric acid (0.5-2.0 M HCl) as well as hydrogen peroxide and hydrochloric acid (0.5-3.0 M H2O2, 1.0 M HCl). The maximum final copper extraction from the slag of 73% was attained with 3 M H2O2, at room temperature after 120 minutes of reaction. At the same time, 55% of the iron from the slag was also dissolved. The copper extraction increased during the first 60 minutes of reaction and essentially ceased thereafter. Because of a rapid catalytic decomposition of hydrogen peroxide, it should be added contiuously to the leach suspension rather than at once at the begining of the experiment. In fact, it appears that almost complete dissolution of copper from the slag is achievable after about 4 hours of leaching by implementing the method of continuous lixiviant addition. Also, it seems that the final iron extraction could be limitied to as low as 20% by using this method.

scholarly journals Sequential leaching of copper from mill tailings with aqueous solutions of hydrochloric acid and sodium hypochlorite

2021 ◽  
Vol 340 ◽  
pp. 01029
Author(s):  
Leilya Syzdykova ◽  
Nargiza Nurtazina ◽  
Aidana Erdenbekova
Keyword(s):  
Hydrochloric Acid ◽  
Aqueous Solutions ◽  
Sodium Hypochlorite ◽  
Maximum Degree ◽  
Room Temperature ◽  
Copper Extraction ◽  
Sequential Leaching ◽  
Mill Tailings ◽  
Copper Leaching ◽  
Kinetics Of

This work presents an investigation of kinetics of copper leaching from mill tailings with hydrochloric acid and sodium hypochlorite at room temperature in filtration mode. The concentration of hydrochloric acid and sodium hypochlorite varied from 0.05 to 0.5 M and 0.025 to 0.1 M respectively. When the samples were leached in the sequence of five-hour leaching with solutions of hydrochloric acid, and then six-hour with sodium hypochlorite, the maximum degree of copper extraction into the solution was 32.62 %. And in case of leaching samples in the inverse direction, with a solution of sodium hypochlorite for two hours, and then with hydrochloric acid for seven hours, 87.10 % of copper was extracted, which is 2.67 times more than in the previous case. It has been shown that the sequence of using reagents in leaching has a significant impact on the efficiency of copper extraction from the tailings.

Intensified-Fenton process for the treatment of phenol aqueous solutions

2014 ◽  
Vol 71 (3) ◽  
pp. 359-365 ◽  
Author(s):  
M. Isabel Pariente ◽  
Raúl Molina ◽  
Juan Antonio Melero ◽  
Juan Ángel Botas ◽  
Fernando Martínez
Keyword(s):  
Hydrogen Peroxide ◽  
Aqueous Solutions ◽  
Heterogeneous Catalyst ◽  
Reaction Temperature ◽  
Catalytic Performance ◽  
Fenton Process ◽  
Iron Species ◽  
Iron Extraction ◽  
Dissolved Iron ◽  
Iron Leaching

An intensified-Fenton process for the treatment of phenol aqueous solutions has been studied as a continuous catalytic wet hydrogen peroxide oxidation system. This process consists of coupling the catalytic activity of a heterogeneous Fenton-like catalyst with the homogeneous contribution of its dissolved iron species. Agglomerated mesoporous SBA-15 silica-supported iron oxide (Fe2O3/SBA-15) material was used as heterogeneous catalyst. The influence of the reaction temperature and the initial hydrogen peroxide dosages was studied in order to minimize the operation cost of the process. The catalytic performance of the process was assessed in terms of total organic carbon (TOC) and hydrogen peroxide conversions. Likewise, the stability of the solid Fenton-like catalyst was also evaluated in terms of the dissolved iron species. The increase of the reaction temperature enhanced the TOC conversion and reduced the iron leaching from the heterogeneous catalyst. These results were related to the degradation of oxalic acid as responsible for iron extraction by formation of soluble stable iron complexes into the aqueous medium. Finally, the use of a moderate hydrogen peroxide concentration (2.6 g/L) and milder temperatures (80–120 °C) has led to remarkable results of TOC and phenol reductions as well as oxidant efficiency through the intensified-Fenton process.

Terpenoid chemistry. XXIV. (1R)-1-Methoxymyodesert-3-ene, an Iridoid Constitutent of Myoporum deserti (Myoporaceae)

1980 ◽  
Vol 33 (4) ◽  
pp. 853 ◽  
Author(s):  
HG Grant ◽  
PJ O'Regan ◽  
RJ Park ◽  
MD Sutherland
Keyword(s):  
Hydrogen Peroxide ◽  
Hydrochloric Acid ◽  
Essential Oil ◽  
Phthalic Acid ◽  
Room Temperature ◽  
Chromic Acid ◽  
Spectral Studies ◽  
Cyclic Acetal ◽  
Common Variety ◽  
Substituted Furans

A common variety of Myoporum deserti A. Cunn. (Ellangowan Poison Bush) yields an essential oil consisting largely of the iridoid monoterpene, (1R)-1-methoxymyodesert-3-ene, C11H18O2,(1R,4aS,7R,7aR)-1-methoxy-4,7- dimethyl-1,4a,5,6,7,7a-hexahydrocycopenta[c]pyran, b.p. 67°/2 mm,[α]D- 165°. This cyclic acetal is hydrolysed to methanol and a mixture of two epimeric cyclopentanoid dialdehydes which are oxidized to the two epimeric trans,trans-nepetalinic acids and yield (+)-(R)-actinidine with Brady's reagent. (1R)-1-Methoxymyodesert-3-ene is oxidized by ozone/hydrogen peroxide to (1R,2R,5R)-2-acetyl-5- methylcyclopentanecarboxylic acid. Hydrogenation yields mainly (1R)- methoxymyodesertan, hydrolysed by aqueous maleic acid at room temperature to methanol and a cyclic hemiacetal, (1R,4R,4aR,7R,7aR)- 4,7-dimethyl-1,3,4,4a,5,6,7,7a-octahydrocyclopenta[c]pyran-1-ol. Oxidation of this cis,cis-hemiacetal by bromine in acetate buffer yields a lactone further oxidized by chromic acid to (2R,1'S,2'R,3'R)- 2-(2'-carboxy-3'-methylcyclopentyl)-propionic acid.��� (1R)-1-Methoxymyodesertan, refluxed with aqueous phthalic acid, yields (+)-(4R,4aR,7R)-4,7-dimethyl-3,4,4a,5,6,7-hexahydrocyclopenta[c]pyran. Treatment of the hexahydropenta[c]pyran, the cis,cis-hemiacetal or (1R)-1-methoxymyodesertan with hydrochloric acid yields a trans,trans-hemiacetal, (1R,4R,4aR,7R,7aS)-4,7-dimethyl- 1,3,4,4a,5,6,7,7a-octahydrocyclopenta[c]pyran-1-ol, which equilibrates in solution to a mixture of α- and β-anomers. Spectral studies of these and otherproducts establish the configuration of the natural product at C1.��� (1R)-1-Methoxymyodesert-3-ene is not toxic to sheep as are the β- substituted furans characteristic of most other chemovarieties of M. deserti.

scholarly journals The phenomena arising from the addition of hydrogen peroxide to the sol of silicic acid

1927 ◽  
Vol 114 (768) ◽  
pp. 517-521
Keyword(s):  
Hydrogen Peroxide ◽  
Hydrochloric Acid ◽  
Sodium Silicate ◽  
Silicic Acid ◽  
Room Temperature ◽  
Gas Bubbles ◽  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Usual Manner ◽  
Acid Gel

The formation of gas bubbles in silicic acid gel (or, in fact, any gel) has been described by Hatschek, and he expresses the view that “such bubbles, which can be produced by a variety of means, are always lenticular, while gas bubbles in a liquid at rest—however viscous—are, of course, spherical. It is possible to produce such bubbles during the transformation, and to note an abrupt change from the spherical to the lenticular shape, which, as stated, cannot be explained by a mere increase in viscosity.” Experimental. Preliminary Experiment. Bubbles were caused to form in the gel of siliic acid in the following manner:— A mixture of equal volumes of sodium silicate solution (D = 1·15) and hydrochloric acid (3N) was prepared in the usual manner (by using solutions of such concentrations as would cause gelation in 1 to 2 hours). After the mixture had cooled down to room temperature, 2 c.c. of twenty-volume hydrogen peroxide solution were added and the resulting mixture allowed to stand. The experiment was carried out in a small rectangular vessel to facilitate observation.

Photoinduced Generation of H2O2 and O2•- by 6-formylpterin in Aqueous Solutions

Pteridines ◽  
2006 ◽  
Vol 17 (3) ◽  
pp. 82-89 ◽  
Author(s):  
Gabriela Petroselli ◽  
Jonas Martin Bartsch ◽  
Andrés H. Thomas
Keyword(s):  
Hydrogen Peroxide ◽  
Aqueous Solutions ◽  
Superoxide Anion ◽  
Anion Radical ◽  
Room Temperature ◽  
Anaerobic Conditions ◽  
White Skin ◽  
Independent Process ◽  
Enzymatic Methods ◽  
Independent Reaction

Abstract 6-Formylpterin is one of the oxidized pterins that accumulate in the white skin patches of patients affected by vitiligo. Studies of photoinduced generation of hydrogen peroxide (H2O2 ) and superoxide anion radical (O2• ) by formylpterin in acidic and alkaline aqueous solutions at 350 nm and room temperature have been performed. The photochemical processes were followed by UV-V1S spectrophotometry and enzymatic methods for H2O2 and O2•- determination. When formylpterin is irradiated a red intermediate, that has been proposed to be 6-carboxy- 5,8-dihydropterin, is generated in an O2-independent process. In the presence of air that intermediate reacts with O2 to yield H2O2 and 6-carboxyptcrin. In anaerobic conditions it undergoes a thermal O2-independent reaction which leads to a non-identified product without generation of H202 . The rate constants of such a process were determined to be 0.011 min 1 and 0.044 min1 at pH 5.4 and 10.5, respectively. (O2 · ), is also generated during photooxidation of formylpterin, probably as a consequence of the electron transfer from the red intermediate to O2 . The biomedical importance of photoinduced generation of H2O2 and O2• is discussed.

Kinetics of copper extraction from copper smelting slag by pressure oxidative leaching with sulfuric acid

2020 ◽  
Vol 241 ◽  
pp. 116699 ◽  
Author(s):  
Gongchu Shi ◽  
Yalong Liao ◽  
Bowen Su ◽  
Yu Zhang ◽  
Wei Wang ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Copper Smelting ◽  
Copper Extraction ◽  
Oxidative Leaching ◽  
Smelting Slag ◽  
Kinetics Of

scholarly journals Influence of a Polycarboxylate Based Solution on Stability of Hydrogen Peroxide and Application to E-waste Leaching

2020 ◽  
Vol 26 (1) ◽  
pp. 17-23
Author(s):  
Ersin Y. Yazici
Keyword(s):  
Hydrogen Peroxide ◽  
Printed Circuit Boards ◽  
Catalytic Decomposition ◽  
Copper Extraction ◽  
Circuit Boards ◽  
H2o2 Decomposition ◽  
Printed Circuit ◽  
High Consumption ◽  
Alkaline Conditions ◽  
Extraction Of Metals

Hydrogen peroxide with its high oxidising potential is commonly used in hydrometallurgical extraction of metals from ores, anode slimes and waste materials (e.g. WEEE) and treatment of cyanidation effluents. Main detraction to H2O2 is its rapid catalytic decomposition leading to prohibitively high consumption. Effect of pH (0-4), Cu(II) (0-10 g.l-1) and temperature (20-80°C) on H2O2 stability was investigated using response surface methodology. Influence of neutral-alkaline conditions (pH 7.3-11.8) and presence of solids (1-20% w/v) was also tested. A polycarboxylate based solution (PBS) was utilised to improve H2O2 stabilisation. The significance order of parameters on H2O2 decomposition was temperature > pH > Cu(II). Elevating the level of these parameters increased H2O2 decomposition. The activation energy (60.7±2.5 kJ.mol-1) indicated a chemically controlled process. Alkaline conditions (up to pH 11.8) led to higher H2O2 decomposition. Presence of solids adversely affected H2O2 stability under certain conditions. The addition of PBS significantly improved (up to 54%) H2O2 stability in the presence of copper. The presence of PBS in H2SO4-H2O2 leaching of waste of printed circuit boards (WPCBs) enhanced copper extraction by up to 19%. PBS can be suitably utilised to stabilise and hence reduce H2O2 consumption in aqueous solutions particularly in the presence of copper.

scholarly journals Chalcopyrite Leaching with Hydrogen Peroxide and Iodine Species in Acidic Chloride Media at Room Temperature: Technical and Economic Evaluation

Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1567
Author(s):  
Germán A. Moraga ◽  
Nathalie E. Jamett ◽  
Pía C. Hernández ◽  
Teófilo A. Graber ◽  
María E. Taboada
Keyword(s):  
Hydrogen Peroxide ◽  
Economic Evaluation ◽  
Room Temperature ◽  
Copper Concentration ◽  
Unit Cost ◽  
Copper Extraction ◽  
Extraction Percentage ◽  
Leaching Solution ◽  
Acidic Chloride ◽  
Influential Variable

In Chile, the hydrometallurgical plants are operating below their capacity due to a depletion of copper oxide ores. To obtain suitable pregnant leach solutions (PLSs) for hydrometallurgical plants, leaching solutions combining iodine-based oxidants and hydrogen peroxide in a chloride–acid medium, at room temperature and pressure were studied. Factorial experiments were conducted to evaluate the effects of the different leaching solution reagents (KI, NaIO3, NaCl, H2O2, and H2SO4). The results showed that the most influential variable is the H2O2 concentration; increasing the PLS concentration from 3 g/L to 15 g/L increased the copper extraction percentage by ~25%. In decreasing order of importance, the factorial experimental results showed that the H2O2, H2SO4, NaCl, NaIO3, and KI concentrations affect the copper extraction percentage. The highest copper extraction percentage (i.e., 60.6%) was obtained using a leaching solution containing the highest reagent concentrations. At these conditions, the copper concentration in the PLS was 16.9 g/L. An economic evaluation of the laboratory-scale leaching experiments showed an increase in the unit cost (USD/t Cu) for experiments involving leaching solutions without H2O2 because of poor copper concentration in the PLS. As the concentrations of the reagents NaIO3 and KI, increase, the unit cost increases, because the reagents are relatively expensive and have a limited effect on the copper extraction percentage.

Sign in / Sign up

Export Citation Format

Share Document