scholarly journals Chemical Dissolution of Chalcopyrite Concentrate in Choline Chloride Ethylene Glycol Deep Eutectic Solvent

Minerals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 65
Author(s):  
Carlos Carlesi ◽  
Robert C. Harris ◽  
Andrew P. Abbott ◽  
Gawen R. T. Jenkin

Currently, the high demand for copper is in direct contrast with the decrease in the mineral grade and, more significantly, the concerns regarding the environmental impact that arise as a result of processing such low-grade materials. Consequently, new mineral processing concepts are needed. This work explores the chemical dissolution of chalcopyrite concentrate at ambient pressure and moderate temperatures in a deep eutectic solvent. Copper and iron are dissolved without changing their oxidation state, without solvent pH change, and stabilized as a chloride complex with no evidence of passivation. Chemical equilibria of the metallic chloride complexes limit the dissolution, and the step that is rate-controlling of the kinetics is the interdiffusion of species in the solvent. The chemical mechanism may involve initial chloride adsorption at positive sites of the solid surface, pointing out the importance of surfaces states on chalcopyrite particles. A model based on a shrinking particle coupled with pseudo-second-order increase in the liquid concentration of copper describes the dissolution kinetics and demonstrates the importance of the liquid to solid ratio. Iron and copper can be recovered separately from the solvent, which highlights that this concept is an interesting alternative to both redox-hydrometallurgy and pyrometallurgy to obtain copper by the processing of chalcopyrite concentrate.

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.


2016 ◽  
Vol 12 ◽  
pp. 1-4 ◽  
Author(s):  
David O. Oseguera-Galindo ◽  
Roberto Machorro-Mejia ◽  
Nina Bogdanchikova ◽  
Josue D. Mota-Morales

2021 ◽  
Vol 60 (5) ◽  
pp. 2011-2026
Author(s):  
Eng Kein New ◽  
Ta Yeong Wu ◽  
Khai Shing Voon ◽  
Alessandra Procentese ◽  
Katrina Pui Yee Shak ◽  
...  

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1170
Author(s):  
Yuan Zhu ◽  
Benkun Qi ◽  
Xinquan Liang ◽  
Jianquan Luo ◽  
Yinhua Wan

Herein, corn stover (CS) was pretreated by less corrosive lewis acid FeCl3 acidified solutions of neat and aqueous deep eutectic solvent (DES), aqueous ChCl and glycerol at 120 °C for 4 h with single FeCl3 pretreatment as control. It was unexpected that acidified solutions of both ChCl and glycerol were found to be more efficient at removing lignin and xylan, leading to higher enzymatic digestibility of pretreated CS than acidified DES. Comparatively, acidified ChCl solution exhibited better pretreatment performance than acidified glycerol solution. In addition, 20 wt% water in DES dramatically reduced the capability of DES for delignification and xylan removal and subsequent enzymatic cellulose saccharification of pretreated CS. Correlation analysis showed that enzymatic saccharification of pretreated CS was highly correlated to delignification and cellulose crystallinity, but lowly correlated to xylan removal. Recyclability experiments of different acidified pretreatment solutions showed progressive decrease in the pretreatment performance with increasing recycling runs. After four cycles, the smallest decrease in enzymatic cellulose conversion (22.07%) was observed from acidified neat DES pretreatment, while the largest decrease (43.80%) was from acidified ChCl pretreatment. Those findings would provide useful information for biomass processing with ChCl, glycerol and ChCl-glycerol DES.


Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2149
Author(s):  
Chan-Woo Park ◽  
Song-Yi Han ◽  
Rajkumar Bandi ◽  
Ramakrishna Dadigala ◽  
Eun-Ah Lee ◽  
...  

In this study, the effect of lignin esterification with fatty acid chloride on the properties of lignin and lignin/poly(lactic acid) (PLA) composites was investigated. Lignocellulose (Pinus densiflora S. et Z.) was treated using a deep eutectic solvent (DES) with choline chloride (ChCl)/lactic acid (LA). From the DES-soluble fraction, DES-lignin (DL) was isolated by a regeneration process. Lignin esterification was conducted with palmitoyl chloride (PC). As the PC loading increased for DL esterification, the Mw of esterified DL (EDL) was increased, and the glass transition temperature (Tg) was decreased. In DL or EDL/PLA composite films, it was observed that EDL/PLA had cleaner and smoother morphological characteristics than DL/PLA. The addition of DL or EDL in a PLA matrix resulted in a deterioration of tensile properties as compared with neat PLA. The EDL/PLA composite film had a higher tensile strength and elastic modulus than the DL/PLA composite film. DL esterification decreased water absorption with lower water diffusion coefficients. The effect of lignin esterification on improving the compatibility of lignin and PLA was demonstrated. These results are expected to contribute to the development of high-strength lignin composites.


2021 ◽  
Vol 23 (3) ◽  
pp. 1300-1311 ◽  
Author(s):  
Dasom Jung ◽  
Jae Back Jung ◽  
Seulgi Kang ◽  
Ke Li ◽  
Inseon Hwang ◽  
...  

The in vitro and in vivo studies suggest that choline chloride-based deep eutectic solvents may not be considered as pure, safe mixtures even if they consist of safe compounds.


2021 ◽  
Vol 255 ◽  
pp. 117443
Author(s):  
Huiqiang Wang ◽  
Jiachen Li ◽  
Xin Yu ◽  
Guihua Yan ◽  
Xing Tang ◽  
...  

2021 ◽  
Vol 56 (5) ◽  
Author(s):  
Lucie Percevault ◽  
Thomas Delhaye ◽  
Alain Chaumont ◽  
Rachel Schurhammer ◽  
Ludovic Paquin ◽  
...  

2020 ◽  
Vol 32 (4) ◽  
pp. 733-738 ◽  
Author(s):  
R. Manurung ◽  
Taslim ◽  
A.G.A. Siregar

Deep eutectic solvents (DESs) have numerous potential applications as cosolvents. In this study, use of DES as organic solvents for enzymatic biodiesel production from degumming palm oil (DPO) was investigated. Deep eutectic solvent was synthesized using choline chloride salt (ChCl) compounds with glycerol and 1,2-propanediol. Deep eutectic solvent was characterized by viscosity, density, pH and freezing values, which were tested for effectiveness by enzymatic reactions for the production of palm biodiesel with raw materials DPO. Deep eutectic solvent of ChCl and glycerol produced the highest biodiesel yield (98.98%); weight of DES was only 0.5 % of that of the oil. In addition, the use of DES maintained the activity and stability of novozym enzymes, which was assessed as the yield until the 6th usage, which was 95.07 % biodiesel yield compared with the yield without using DES. Hence, using DES, glycerol in enzymatic biodiesel production had high potentiality as an organic solvent for palm oil biodiesel production


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