scholarly journals Study on Intensification Behavior of Bismuth Ions on Gold Cyanide Leaching

Metals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 362 ◽  
Author(s):  
Yongbin Yang ◽  
Meixiang Lai ◽  
Qiang Zhong ◽  
Qian Li ◽  
Bin Xu ◽  
...  
Keyword(s):  
Anodic Dissolution ◽  
Gold Surface ◽  
Corrosion Current ◽  
Electrochemical Analysis ◽  
Anode Current Density ◽  
Gold Cyanide ◽  
Cyanide Leaching ◽  
Structure Information ◽  
Passivation Film ◽  
Gold Plate

Gold cyanide leaching is inefficient with conventional cyanidation. Bismuth ions can improve the efficiency of gold cyanidation by intensifying gold dissolution. The electrochemical behavior, structure information, and surface product of gold anodic dissolution were studied during the intensification of bismuth ions on gold cyanide leaching. The electrochemical analysis showed that the bismuth ions can not only improve anode current density, but also make gold dissolve at a lower potential, increase the corrosion current and intensify gold anodic dissolution. The microstructure analysis showed that bismuth ions intensified the cyanide corrosion of the gold surface, causing a large number of loose honeycombs, gullies, pits, and large holes on the gold surface. The XPS, FT-IR, and Raman analysis showed that there is weak information of C≡N in the spectrum of Bi intensification contrasting to that of conventional cyanidation. Cyanide compounds may be the insoluble AuCNads, which does not deposit on the surface of gold plate after Bi intensification cyanidation. The insoluble intermediate AuCNads is likely to react promptly with CN- to form soluble Au(CN ) 2 − , making less insoluble AuCNads deposits on the gold surface. Therefore, bismuth ions can promote the dissolution of insoluble AuCNads, prevents its passivation film to cover around the gold plate, keeps cyanide good contact with gold, and finally accelerates the cyanide dissolution of gold.

Microstructure and Properties of 304 Stainless Steel Specimen Manufactured by Cold Metal Transfer + Pulse Composite Arc Additive

2021 ◽  
Vol 13 (1) ◽  
pp. 152-160
Author(s):  
Yanjie Wang ◽  
Xuru Hou ◽  
Lin Zhao ◽  
Yun Peng ◽  
Chengyong Ma ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Additive Manufacturing ◽  
Fracture Surface ◽  
Steel Specimen ◽  
Corrosion Current ◽  
Electrochemical Analysis ◽  
304 Stainless Steel ◽  
Cold Metal Transfer ◽  
Σ Phase ◽  
Microstructure And Properties

304 stainless steel test block was fabricated by continuous melting wire with CMT and pulse mixed mode, and the path of additive manufacturing is layered slice S-shaped. The relationship between microstructure and properties of the specimen was investigated by microscope, SEM, EBSD, XRD, tensile, impact and electrochemical experiments. The results show that molding between weld and weld is very good, and the microstructure is mainly Austenite, Ferrite and a little of σ, and there are three kinds of Ferrite morphology: cellular, wormlike and lath. σ phase precipitates easily in regions with high ferrite content and is distributed at the boundary between austenite and ferrite. The specimen has good low temperature toughness. The microscopic fracture surface is mainly dimple, and the precipitates in the fracture surface are mainly fine carbide particles. The tensile strength of the additive manufacturing 304 specimen is higher than the forged specimen, and the type of fracture is ductile fracture. The electrochemical analysis of 304 stainless steel specimens and forgings shows that CMT and pulse arc additive manufacturing specimen has excellent corrosion resistance and its corrosion current is slightly lower than the forging.

Corrosion Protection and Microstructure of Magnesium Alloys Anodized by Phosphate Solution

2010 ◽  
Vol 638-642 ◽  
pp. 1464-1469
Author(s):  
Koji Murakami ◽  
Makoto Hino ◽  
Atsushi Saijo ◽  
Teruto Kanadani
Keyword(s):  
Sodium Chloride ◽  
Magnesium Oxide ◽  
Magnesium Alloys ◽  
Corrosion Protection ◽  
Corrosion Current ◽  
Electrochemical Analysis ◽  
The State ◽  
Phosphate Solution ◽  
Protective Films ◽  
Sacrificial Protection

Corrosion protection by anodization and conversion treatment in phosphate solution was studied by microstructural and electrochemical analysis. Both the anodized and the conversion-treated layers showed sacrificial protection in a solution of sodium chloride. The corrosion current or the dissolving rate of the anodized layer was smaller than that of the conversion-treated surface. The modified layers had another mode of protection to form protective films on magnesium substrate where the original modified layers were mechanically lost. Since the state of magnesium in the anodized layer is close to magnesium oxide, phosphorus in the layer is considered to have an important role in these properties concerning the above corrosion protection.

The Effect of Grain Size and Cl-Concentration on the Passive Behavior of Cu in Borate Buffer Solution

2013 ◽  
Vol 785-786 ◽  
pp. 928-932 ◽  
Author(s):  
Qi Jun Zhong ◽  
Li Bin Yu ◽  
Yi Xiao ◽  
Yi Wang ◽  
Qiong Yu Zhou ◽  
...  
Keyword(s):  
Grain Size ◽  
Electrochemical Analysis ◽  
Borate Buffer ◽  
Borate Buffer Solution ◽  
Buffer Solution ◽  
Solution Ph ◽  
Passivation Film ◽  
Passive Behavior ◽  
Anode Passivation ◽  
Passivation Potential

Effect of grain size and Cl-concentration on corrosion behavior of Cu was investigated by using a series of electrochemical analysis in borate buffer solution (pH=8.40).The results indicated that in all cases, the Mott-Schottky plots of the passive films on the surface of Cu were linear with negative slop, and showed behavior of the p-type semiconductor.With the decrease of the grain size and the increase of anode passivation potential, the acceptor density (NA) of the passivation film on the surface of Cu was reducing. As the concentration of Cl-in the medium solution was heightening, the acceptor density (NA) of the passivation film on the surface of Cu was increasing.

Study on Corrosion Resistance and Mechanical Property of Welding HAZ Treated by Laser Surface Remelting

2013 ◽  
Vol 734-737 ◽  
pp. 2346-2350 ◽  
Author(s):  
Yan Li Li ◽  
Jia Rui Qi ◽  
Dan Feng Zhang ◽  
Ji Liu ◽  
Chao Li
Keyword(s):  
Mechanical Property ◽  
Corrosion Resistance ◽  
Corrosion Current ◽  
Processing Parameters ◽  
Electrochemical Analysis ◽  
Constructional Steel ◽  
Orthogonal Test ◽  
Laser Surface ◽  
Laser Remelting ◽  
Laser Surface Remelting

Welding is a main joint way of the alloy constructional steel. However, the welding HAZ is very sensitive to corrosion. In order to increase the corrosion resistance of the welding HAZ without reducing mechanical property of the parts simultaneously, the laser surface remelting was used to treat the welding HAZ in this study. According to the results of the orthogonal test, the optimized processing parameters were obtained. Based on the electrochemical analysis, the corrosion current of 30CrMnSi welding HAZ can be decreased by laser remelting technology. The corrosion resistance of the HAZ can be improved effectively. At the same time, the mechanical property of the treated welding HAZ was better compared with the untreated.

Synthesis and Characterization of Chrom-Free Dark Coating on AA6063 Aluminium Alloy with K2ZrF6

2014 ◽  
Vol 1053 ◽  
pp. 421-428
Author(s):  
Ting Yi Chen ◽  
Ye Qi Fu ◽  
Wen Lu ◽  
Wen Fang Li
Keyword(s):  
Corrosion Resistance ◽  
Aluminium Alloy ◽  
Corrosion Current ◽  
Visual Assessment ◽  
Electrochemical Analysis ◽  
Conversion Coating ◽  
Electrochemical Tests ◽  
Excellent Corrosion Resistance ◽  
New Treatment

A new passivation process has been developed for producing a chrome-free and coloured conversion coating on aluminium alloy AA6063 with K2ZrF6. The conversion coating obtained has a dark film, which enables visual assessment of the coating development and coating quality during processing. The colouring effect is a significant advantage over the zirconium based conversion coatings currently used in the industry, which are largely colourless. The new treatment process is simple and allows a uniform coating to be formed within a few minutes. The composition and the surface morphology of the coatings were characterized. The corrosion resistance of the coated samples was evaluated by electrochemical tests. Through electrochemical analysis, corrosion current of the coatings is low, it has excellent corrosion resistance; SEM, EDS and XRD are used to analyze the process coating.

Passivator Composition of Rich of Phytic Acid Used for Brass-Strip

2011 ◽  
Vol 399-401 ◽  
pp. 36-39 ◽  
Author(s):  
Wei Cai ◽  
Li Li ◽  
Ren Hui Liu ◽  
Zhen Zhen Wan
Keyword(s):  
Hydrogen Peroxide ◽  
Polyethylene Glycol ◽  
Boric Acid ◽  
Phytic Acid ◽  
Mass Fraction ◽  
Orthogonal Experiment ◽  
Corrosion Current ◽  
Sodium Dichromate ◽  
Electrochemical Test ◽  
Passivation Film

Passivator components of phytic acid, hydrogen peroxide, boric acid and polyethylene glycol was optimized by orthogonal experiment. Corrosion resistance of passivation film of brass-strip was invertigated by salt spraying, weight loss and electrochemical test. The results show that the optimization passivator consists of phytic acid (50% mass fraction) 8ml/L, hydrogen peroxide (mass fraction 30%) 30ml/L, boric acid 5g/L, polyethylene glycol 15ml/L and additive 4g/L. Corrosion current density and corrosion rate of the brass-strip specimens coated by rich-phytic acid passivator are similar to that treated by traditional sodium dichromate passivator, the characteristic of anti-tarnish slightly better than that coated by sodium dichromate passivator. The feature of rich-phytic acid passivator is environmental protection.

scholarly journals Intensification Behavior of Mercury Ions on Gold Cyanide Leaching

Metals ◽  
2018 ◽  
Vol 8 (1) ◽  
pp. 80 ◽  
Author(s):  
Qiang Zhong ◽  
Yongbin Yang ◽  
Lijuan Chen ◽  
Qian Li ◽  
Bin Xu ◽  
...  
Keyword(s):  
Mercury Ions ◽  
Gold Cyanide ◽  
Cyanide Leaching

Electrochemical Investigations of Microbiologically Influenced Corrosion on 316L-Cu Stainless Steel by Pseudoalteromonas lipolytica

2020 ◽  
Vol 12 (2) ◽  
pp. 191-199 ◽  
Author(s):  
Phuri Kalnaowakul ◽  
Trinet Yingsamphancharoen ◽  
Ke Yang ◽  
Dake Xu ◽  
Aphichart Rodchanarowan
Keyword(s):  
Corrosion Current Density ◽  
Marine Bacterium ◽  
Induction Furnace ◽  
Cooling Water ◽  
Corrosion Current ◽  
Water Systems ◽  
Electrochemical Analysis ◽  
Microbiologically Influenced Corrosion ◽  
Vacuum Induction Furnace ◽  
Corrosion Resistant

Microbiologically influenced corrosion (MIC) is becoming more often a risk factor in several industries, such as offshore, cooling water systems and construction. The Pseudoalteromonas lipolytica (P. lipolytica) is a highly corrosive aerobic marine bacterium. In this work, the 316L-Cu SS was investigated the corrosion behavior under the abiotic medium and biotic medium of P. lipolytica. Based on the electrochemical analysis, the corrosion current density (icorr) under the biotic medium is higher than that under the abiotic medium. The presence of P. lipolytica has led to the dissolution of the passive film of 316L-Cu SS, which initiates the localized pitting corrosion. However, the addition of Cu in 316L SS by melting in the vacuum induction furnace improved more corrosion-resistant than without the addition of Cu.

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