Pretreatment of low-grade shredded dust e-waste to enhance silver recovery through biocyanidation by Pseudomonas balearica SAE1

3 Biotech ◽  
2021 ◽  
Vol 11 (11) ◽  
Author(s):  
Pooja Thakur ◽  
Sudhir Kumar
2012 ◽  
Vol 581-582 ◽  
pp. 1110-1114
Author(s):  
Hong Xiao ◽  
Quan Jun Liu ◽  
Mei Guang Jiang ◽  
Jun Long Yang

The lead-zinc mine is a low grade of refractory oxide mineral. The grade of lead is 2.84%, with the oxidation rate of 90.95%.The grade of zinc is 3.223%, and with the oxidation rate of 87.9%.The grade of silver is 99.5g/t.This test used the silver-lead sulphide flotation at first, then depressing zinc oxide and floating lead oxide mineral. As a result, in silver-lead sulphide concentrate, the silver grade for 1180 g/t, lead 11.45%. Lead and silver recovery rate were 18.41% and 51.14% respectively. Lead oxide concentrate grade is 32.59%, and the silver is 518g/t. Lead and silver recovery rate were 68.34% and 29.18%. Zinc oxide concentrate grade is 32.65%, including 1.14% lead; zinc recovery rate is 80.11%.


2020 ◽  
Author(s):  
Abiodun Aderibigbe ◽  
Andrew J. Clark

Ligands bearing <i>S</i>- and <i>N</i>- donors are an important class of extractants with demonstrated efficiency and selectivity for Ag<sup>+</sup> extraction over metals with similar chemistries. However, the synthesis of some of these ligands can be complicated and low yielding. Here, we report the synthesis of a novel ligand - <i>N</i>-(2-((4-vinylbenzyl)thio)ethyl)acetamide, over two simple steps and in a good yield. The extractant was observed to demonstrate excellent selectivity for Ag<sup>+</sup>, extracting only Ag<sup>+</sup> from an aqueous solution also containing Cu<sup>2+</sup> and Pb<sup>2+</sup>. Moderate extraction efficiencies of 36 % for Ag<sup>+</sup> and 0% each for Cu<sup>2+</sup> and Pb<sup>2+</sup> were observed. From mass spectrometry and proton NMR titration data, the extractant was found to form both the 1:1 and 1:2 (Ag<sup>+</sup>:ligand) complexes with Ag<sup>+ </sup>indicating that ligand forms bent linear and tetrahedral coordination complexes with Ag<sup>+</sup>. Overall, the results indicate that the novel amide-based ligand is highly selective for Ag<sup>+</sup> removal from aqueous solutions containing Cu<sup>2+</sup> and Pb<sup>2+</sup>. These results indicate the ligand could be easily synthesized and applied for selective silver recovery from low grade ores.


2020 ◽  
Author(s):  
Abiodun Aderibigbe ◽  
Andrew J. Clark

Ligands bearing <i>S</i>- and <i>N</i>- donors are an important class of extractants with demonstrated efficiency and selectivity for Ag<sup>+</sup> extraction over metals with similar chemistries. However, the synthesis of some of these ligands can be complicated and low yielding. Here, we report the synthesis of a novel ligand - <i>N</i>-(2-((4-vinylbenzyl)thio)ethyl)acetamide, over two simple steps and in a good yield. The extractant was observed to demonstrate excellent selectivity for Ag<sup>+</sup>, extracting only Ag<sup>+</sup> from an aqueous solution also containing Cu<sup>2+</sup> and Pb<sup>2+</sup>. Moderate extraction efficiencies of 36 % for Ag<sup>+</sup> and 0% each for Cu<sup>2+</sup> and Pb<sup>2+</sup> were observed. From mass spectrometry and proton NMR titration data, the extractant was found to form both the 1:1 and 1:2 (Ag<sup>+</sup>:ligand) complexes with Ag<sup>+ </sup>indicating that ligand forms bent linear and tetrahedral coordination complexes with Ag<sup>+</sup>. Overall, the results indicate that the novel amide-based ligand is highly selective for Ag<sup>+</sup> removal from aqueous solutions containing Cu<sup>2+</sup> and Pb<sup>2+</sup>. These results indicate the ligand could be easily synthesized and applied for selective silver recovery from low grade ores.


Minerals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 434
Author(s):  
Yibing Zhang ◽  
Jianhua Chen

In this study, we investigate a low-grade oxidized lead ore containing noble metal silver, with complex mineralogy. The sulfurization behaviors of different types of lead-silver minerals at different pH values were analyzed using the chemical phase analysis method. The interactions between different types of lead-silver minerals and different types of collectors were investigated. An effective laboratory process was developed, and closed-circuit tests were carried out at industrial sites. We found that the order of difficulty for sulfidizing various lead minerals and silver minerals was (PbFe6(OH)12SO4)4 < PbCO3 < PbSO4 < Pb5(P/As/VO4)3Cl; Ag2AsS2 < AgCl < natural-Ag. Aerophine 3418A had the best selectivity and capture capacity of the silver minerals. In the laboratory, the total recovery of lead and silver was 65.16% and 87.81%, respectively. In industrial closed-circuit testing, flotation alone was used, which produced a total lead recovery yield of 67.71%, and a total silver recovery yield of 87.64%.


Author(s):  
Thomas R. McKee ◽  
Peter R. Buseck

Sediments commonly contain organic material which appears as refractory carbonaceous material in metamorphosed sedimentary rocks. Grew and others have shown that relative carbon content, crystallite size, X-ray crystallinity and development of well-ordered graphite crystal structure of the carbonaceous material increases with increasing metamorphic grade. The graphitization process is irreversible and appears to be continous from the amorphous to the completely graphitized stage. The most dramatic chemical and crystallographic changes take place within the chlorite metamorphic zone.The detailed X-ray investigation of crystallite size and crystalline ordering is complex and can best be investigated by other means such as high resolution transmission electron microscopy (HRTEM). The natural graphitization series is similar to that for heat-treated commercial carbon blacks, which have been successfully studied by HRTEM (Ban and others).


Author(s):  
V.K. Berry

There are two strains of bacteria viz. Thiobacillus thiooxidansand Thiobacillus ferrooxidanswidely mentioned to play an important role in the leaching process of low-grade ores. Another strain used in this study is a thermophile and is designated Caldariella .These microorganisms are acidophilic chemosynthetic aerobic autotrophs and are capable of oxidizing many metal sulfides and elemental sulfur to sulfates and Fe2+ to Fe3+. The necessity of physical contact or attachment by bacteria to mineral surfaces during oxidation reaction has not been fairly established so far. Temple and Koehler reported that during oxidation of marcasite T. thiooxidanswere found concentrated on mineral surface. Schaeffer, et al. demonstrated that physical contact or attachment is essential for oxidation of sulfur.


Author(s):  
Gejing Li ◽  
D. R. Peacor ◽  
D. S. Coombs ◽  
Y. Kawachi

Recent advances in transmission electron microscopy (TEM) and analytical electron microscopy (AEM) have led to many new insights into the structural and chemical characteristics of very finegrained, optically homogeneous mineral aggregates in sedimentary and very low-grade metamorphic rocks. Chemical compositions obtained by electron microprobe analysis (EMPA) on such materials have been shown by TEM/AEM to result from beam overlap on contaminant phases on a scale below resolution of EMPA, which in turn can lead to errors in interpretation and determination of formation conditions. Here we present an in-depth analysis of the relation between AEM and EMPA data, which leads also to the definition of new mineral phases, and demonstrate the resolution power of AEM relative to EMPA in investigations of very fine-grained mineral aggregates in sedimentary and very low-grade metamorphic rocks.Celadonite, having end-member composition KMgFe3+Si4O10(OH)2, and with minor substitution of Fe2+ for Mg and Al for Fe3+ on octahedral sites, is a fine-grained mica widespread in volcanic rocks and volcaniclastic sediments which have undergone low-temperature alteration in the oceanic crust and in burial metamorphic sequences.


2020 ◽  
Vol 134 (17) ◽  
pp. 2243-2262
Author(s):  
Danlin Liu ◽  
Gavin Richardson ◽  
Fehmi M. Benli ◽  
Catherine Park ◽  
João V. de Souza ◽  
...  

Abstract In the elderly population, pathological inflammation has been associated with ageing-associated diseases. The term ‘inflammageing’, which was used for the first time by Franceschi and co-workers in 2000, is associated with the chronic, low-grade, subclinical inflammatory processes coupled to biological ageing. The source of these inflammatory processes is debated. The senescence-associated secretory phenotype (SASP) has been proposed as the main origin of inflammageing. The SASP is characterised by the release of inflammatory cytokines, elevated activation of the NLRP3 inflammasome, altered regulation of acetylcholine (ACh) nicotinic receptors, and abnormal NAD+ metabolism. Therefore, SASP may be ‘druggable’ by small molecule therapeutics targeting those emerging molecular targets. It has been shown that inflammageing is a hallmark of various cardiovascular diseases, including atherosclerosis, hypertension, and adverse cardiac remodelling. Therefore, the pathomechanism involving SASP activation via the NLRP3 inflammasome; modulation of NLRP3 via α7 nicotinic ACh receptors; and modulation by senolytics targeting other proteins have gained a lot of interest within cardiovascular research and drug development communities. In this review, which offers a unique view from both clinical and preclinical target-based drug discovery perspectives, we have focused on cardiovascular inflammageing and its molecular mechanisms. We have outlined the mechanistic links between inflammageing, SASP, interleukin (IL)-1β, NLRP3 inflammasome, nicotinic ACh receptors, and molecular targets of senolytic drugs in the context of cardiovascular diseases. We have addressed the ‘druggability’ of NLRP3 and nicotinic α7 receptors by small molecules, as these proteins represent novel and exciting targets for therapeutic interventions targeting inflammageing in the cardiovascular system and beyond.


Sign in / Sign up

Export Citation Format

Share Document