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.

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 Input of Protein to Lake Water Microcosms Affects Expression of Proteolytic Enzymes and the Dynamics ofPseudomonas spp

2001 ◽  
Vol 67 (11) ◽  
pp. 4955-4962 ◽  
Author(s):  
Jakob Worm ◽  
Ole Nybroe
Keyword(s):  
Population Structure ◽  
Lake Water ◽  
Leucine Aminopeptidase ◽  
Proteolytic Enzymes ◽  
Extracellular Enzyme ◽  
Bacterial Consortium ◽  
Proteinase Activity ◽  
Aminopeptidase Activity ◽  
Growth Media ◽  
Hydrolysis Of

ABSTRACT The objective of this study was to determine how an input of protein to lake water affects expression of a proteolytic potential and influences the abundance and composition of a specific group of bacteria. Pseudomonas spp. were chosen as a target group that can be recovered on selective growth media and contain both proteolytic and nonproteolytic strains. Amendment with 2 mg of casein per liter increased total proteinase activity (hydrolysis of [3H]casein) by 74%, leucine-aminopeptidase activity (hydrolysis of leucine-methyl-coumarinylamide) by 133%, bacterial abundance by 44%, and phytoplankton biomass (chlorophylla) by 39%. The casein amendment also increased the abundance of culturable Pseudomonas spp. by fivefold relative to control microcosms but did not select for proteolytic isolates. Soluble proteins immunochemically related to thePseudomonas fluorescens alkaline proteinase, AprX, were detected in amended microcosms but not in the controls. The expression of this class of proteinase was confirmed exclusively for proteolyticPseudomonas isolates from the microcosms. The population structure of Pseudomonas isolates was determined from genomic fingerprints generated by universally primed PCR, and the analysis indicated that casein amendment led to only minor shifts in population structure. The appearance of AprX-like proteinases in the lake water might thus reflect a general induction of enzyme expression rather than pronounced shifts in the Pseudomonaspopulation structure. The limited effect of casein amendment onPseudomonas population structure might be due to the availability of casein hydrolysates to bacteria independent of their proteinase expression. In the lake water, 44% of the total proteinase activity was recovered in 0.22-μm-pore-size filtrates and thus without a direct association with the bacteria providing the extracellular enzyme activity. Since all Pseudomonasisolates expressed leucine-aminopeptidase in pure culture, proteolytic as well as nonproteolytic pseudomonads were likely members of the bacterial consortium that metabolized protein in the lake water.

Selective Acid Leaching of Copper and Zinc from Old Flotation Tailings

2020 ◽  
Vol 989 ◽  
pp. 554-558
Author(s):  
Aleksandr Bulaev ◽  
Vitaliy Melamud
Keyword(s):  
Sulfuric Acid ◽  
Acid Leaching ◽  
Distilled Water ◽  
Acid Solutions ◽  
Iron Ions ◽  
Flotation Tailings ◽  
Ferrous Metals ◽  
Non Ferrous Metals ◽  
Sulfuric Acid Solutions ◽  
Cu And Zn

The goal of the present work was to develop hydrometallurgical method based on acid leaching, which makes it possible to perform selective extraction of non-ferrous metals from old flotation tailings. Leaching was performed with sulfuric acid solutions (from 0.5 to 10%) and distilled water. Leaching was carried out using percolators and bottle agitator. Percolators were loaded with 100 g of old tailings, and leaching was performed with 100 mL of acid solutions. Pulp density during agitation leaching (S: L) was 1: 5. Two samples of old flotation samples were studied. The first sample of flotation tailings contained 0.26% of copper, 0.22% of zinc, and 17.4% of iron; while the second sample contained 0.36% of copper, 0.23% of zinc, and 23.2% of iron. Percolation leaching made it possible to extract up to 43 and 47% of Cu and Zn from the first sample. Extraction rate was maximum during the leaching with 1 and 2.5% sulfuric acid solutions. During the agitation leaching, the maximum extraction rate was reached with a 2.5% sulfuric acid solution (52 and 54% Cu and Zn), but the leaching rate with all solutions and distilled water differed insignificantly. Percolation leaching made it possible to extract up to 54 and 37% of Cu and Zn from the second sample of tailings, while agitation leaching made it possible to extract up to 34 and 68% Cu and Zn, respectively. The rate of non-ferrous metals extraction from the second sample with water did not differ significantly from that of obtained in the experiments with sulfuric acid solutions. In all experiments, the increase in the H2SO4 concentration led to the increase in concentrations of iron ions in productive solutions, which impedes the extraction of non-ferrous metals from solutions. Thus, it was possible to reach selective leaching of non-ferrous metals and to obtain solutions with relatively low concentrations of iron ions.

Hydrogen Sulphide Production at Alkaline, Neutral and Acid pH by a Bacterial Consortium Isolated from Peruvian Mine Tailing and Wetland

2013 ◽  
Vol 825 ◽  
pp. 384-387
Author(s):  
Juliet Mormontoy ◽  
Jasmin E. Hurtado
Keyword(s):  
Mixed Culture ◽  
Hydrogen Sulphide ◽  
Mine Tailings ◽  
Bacterial Consortium ◽  
Mixed Cultures ◽  
No Production ◽  
Alkaline Ph ◽  
Dissolved Metals ◽  
Biochemical Tests ◽  
Acid Ph

The gol aim of this study is to optimize the ability to produce hydrogen sulphide (H2S) in pure and mixed cultures of sulfate reducing bacteria (SRB) at pH variations from 9 to 5. Hydrogen sulphide produced by SRB reacts with dissolved metals in water or tailings generating highly insoluble metal sulfides and therefore the selective immobilization of different metals. Three strains of SRB were isolated from Orcopampa mine tailings and from the Pantanos de Villa wetlands, both located in Peru. Cultures were identified by microscopy, cultural characteristics and biochemical tests as production of desulfoviridin and growth in different substrates. The production of H2S by pure and mixed cultures was evaluated at: acid pH (5), neutral pH (7) and alkaline pH (9). The mixed culture consisted of all three isolated species:Desulfobactersp. from mine tailings andDesulfovibrio desulfuricansandDesulfovibrio sapovorans from wetland sludges. Pure cultures of these three strains grew and produced H2S at both neutral or alkaline pH. At low pH no pure culture was able to grow and no production of H2S was detected. A mixed culture formed by the three isolated SRB was the only culture that grew and produced sulphide at the three different pH tested in shorter time (24 hours). The improvement of bacterial activity can be based in the metabolic diversity of the mixed culture able to use lactate and acetate as a result of the joint activity of these species. Energy obtained from the substrate is thus used more efficiently.

Determination of Cd, Cu, and Zn in fish and mussel by AAS after ultrasound-assisted acid leaching extraction

2007 ◽  
Vol 101 (2) ◽  
pp. 817-824 ◽  
Author(s):  
Niwat Manutsewee ◽  
Wanlapa Aeungmaitrepirom ◽  
Pakorn Varanusupakul ◽  
Apichat Imyim
Keyword(s):  
Acid Leaching ◽  
Ultrasound Assisted ◽  
Cu And Zn

scholarly journals A Branch Point of Streptomyces Sulfur Amino Acid Metabolism Controls the Production of Albomycin

2015 ◽  
Vol 82 (2) ◽  
pp. 467-477 ◽  
Author(s):  
Aditya Kulkarni ◽  
Yu Zeng ◽  
Wei Zhou ◽  
Steven Van Lanen ◽  
Weiwen Zhang ◽  
...  
Keyword(s):  
Amino Acid ◽  
Process Development ◽  
Random Mutagenesis ◽  
Streptomyces Griseus ◽  
Defined Medium ◽  
Growth Media ◽  
Sulfur Amino Acid ◽  
Content Type ◽  
Promoter Sequences ◽  
Shake Flasks

ABSTRACTAlbomycin (ABM), also known as grisein, is a sulfur-containing metabolite produced byStreptomyces griseusATCC 700974. Genes predicted to be involved in the biosynthesis of ABM and ABM-like molecules are found in the genomes of other actinomycetes. ABM has potent antibacterial activity, and as a result, many attempts have been made to develop ABM into a drug since the last century. Although the productivity ofS. griseuscan be increased with random mutagenesis methods, understanding ofStreptomycessulfur amino acid (SAA) metabolism, which supplies a precursor for ABM biosynthesis, could lead to improved and stable production. We previously characterized the gene cluster (abm) in the genome-sequencedS. griseusstrain and proposed that the sulfur atom of ABM is derived from either cysteine (Cys) or homocysteine (Hcy). The gene product, AbmD, appears to be an important link between primary and secondary sulfur metabolic pathways. Here, we show that propargylglycine or iron supplementation in growth media increased ABM production by significantly changing the relative concentrations of intracellular Cys and Hcy. An SAA metabolic network ofS. griseuswas constructed. Pathways toward increasing Hcy were shown to positively impact ABM production. TheabmDgene and five genes that increased the Hcy/Cys ratio were assembled downstream ofhrdBp promoter sequences and integrated into the chromosome for overexpression. The ABM titer of one engineered strain, SCAK3, in a chemically defined medium was consistently improved to levels ∼400% of the wild type. Finally, we analyzed the production and growth of SCAK3 in shake flasks for further process development.

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