Decomposition of hydrogen peroxide in alkaline cyanide solutions

Fungene, T.; Groot, D.R.; Mahlangu, T.; Sole, Kathryn C.

doi:10.17159/2411-9717/2018/v118n12a4

Cited by 10 publications

(10 citation statements)

References 11 publications

(18 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…in the leaching solution. 14 In the case of the OP group, maximal Co (98.9%), Li (72.5%), Ni (98.2%) and Mn (99.8%), and recovery was observed with 200 mg of OP powder. However, in contrast to the H 2 O 2 group, metal leaching efficiencies did not decrease but plateaued at a nearmaximal with increasing OP concentration.…”

Section: Effect Of Reductant Amountmentioning

confidence: 85%

“…However, at higher amount of H 2 O 2 , a drastic decrease was observed in the leaching efficiencies for all the metals by as much as 20%. This could be attributed to the concentration-dependent self-decomposition of H 2 O 2 , which will severely decrease the availability of the reductant (i.e., H 2 O 2 ) in the leaching solution . In the case of the OP group, maximal Co (98.9%), Li (72.5%), Ni (98.2%), and Mn (99.8%) and recovery were observed with 200 mg of OP powder.…”

Section: Resultsmentioning

confidence: 99%

“…13 In contrast, hydrometallurgy, which makes use of water as a solvent, provides a more direct metal recovery route. In terms of the operational conditions, the processing temperatures in hydrometallurgy (10 to 200 °C) 14 are significantly lower than pyrometallurgy and its efficiency is independent of the growth kinetics of the microbes. Additionally, the low energy consumption, high recovery rate, and ease T h i s c o n t e n t i s of operation associated with hydrometallurgy make it a highly attractive approach to treat LIB waste.…”

Section: ■ Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Repurposing of Fruit Peel Waste as a Green Reductant for Recycling of Spent Lithium-Ion Batteries

Soh

Chan

et al. 2020

Environ. Sci. Technol.

102

View full text Add to dashboard Cite

The development of environmentally-benign hydrometallurgical processes to treat spent lithium ion batteries (LIBs) is a critical aspect of the electronic-waste circular economy. Herein, as an alternative to the highly explosive H 2 O 2 , discarded orange peel powder (OP) is valorized as a green reductant for the leaching of industrially produced LIBs scraps in citric acid (H 3 Cit) lixiviant.The reductive potential of the cellulosic-and antioxidants-rich OP was validated using the 3,5dinitrosalicylic acid and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic) acid assays. Leaching parameters such as OP concentration (200mg), processing temperature (100 o C), H 3 Cit concentration (1.5 M), reaction duration (4 h) and slurry density (25g /ml) were systematically optimized to achieve 80-99% leaching efficiencies of Ni, Mn, Co, and Li from the LIBs "black mass". Importantly, solid side-streams generated by the OP-enabled leaching displayed negligible cytotoxicity in 3 different human cell lines, suggesting that the process is environmentally safe. As a proof-of-concept, Co(OH) 2 was selectively recovered from the green lixiviant and subsequently utilized to fabricate new batches of LiCoO 2 (LCO) coin cell batteries.Galvanostatic charge-discharge test revealed that the regenerated batteries exhibited initial charge and discharge values of 120 mAh/g and 103 mAh/g respectively, which is comparable to

show abstract

Section: Effect Of Reductant Amountmentioning

confidence: 85%

Section: Resultsmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Repurposing of Fruit Peel Waste as a Green Reductant for Recycling of Spent Lithium-Ion Batteries

Soh

Chan

et al. 2020

Environ. Sci. Technol.

102

View full text Add to dashboard Cite

show abstract

“…Despite the one-to-one stoichiometric effectiveness of UV/H 2 O 2 , this process has been shown to be effective for treating cyanide-containing effluents [22,23] and is preferred over other AOPs, such as ozone, because peroxide is relatively inexpensive, water soluble, and simple to store and handle [18]. UV irradiation in combination with hydrogen peroxide (H 2 O 2 ) is also a particularly attractive treatment option [24], as the Arequipa region receives high solar radiation ranging between 850 to 950 W/m 2 and a UV intensity of~0.2 mW/cm 2 , which may be used in place of UV lamps [25]. Titanium dioxide (TiO 2 ) photocatalysts have also been used to accelerate degradation in cyanide containing effluents [26,27], although with varying degrees of success.…”

Section: Introductionmentioning

confidence: 99%

Photocatalytic Advanced Oxidation Processes for Neutralizing Free Cyanide in Gold Processing Effluents in Arequipa, Southern Peru

et al. 2021

View full text Add to dashboard Cite

Cyanide (CN−) from gold processing effluents must be removed to protect human health and the environment. Reducing the use of chemical reagents is desirable for small centralized and decentralized facilities. In this work, we aimed to optimize the use of ultraviolet (UV) radiation coupled with hydrogen peroxide (H2O2) to enhance the rate and extent of CN− removal in synthetic and actual gold processing effluents, from one centralized and one decentralized facility in southern Peru. Bench-scale studies conducted using H2O2 and ambient UV showed no significant effects on CN− destruction; however, experiments with higher UV intensity and H2O2 accelerated free CN− degradation. When a 1:1 stoichiometric ratio of CN−:H2O2 was tested, the highly concentrated effluent (1 g CN−/L) had a slower pseudo first-order rate constant (k = 0.0066 min−1) and took ~5 h longer to reach 99% destruction, compared with the low concentration effluent (100 mg CN−/L; k = 0.0306 min−1). Lastly, a TiO2 photocatalyst with low stoichiometric CN−:H2O2 ratios (1:0.1 and 1:0.2), in a compound parabolic solar concentrator, was tested to investigate the degradation of a high concentration effluent (1.28 g CN−/L). These results show a significant improvement to degradation rate within a 20 min period, advancing treatment options for mineral processing facilities.

show abstract

“…Leaching also requires the presence of an oxidant; thus, an essential source of oxygen (typically air) is introduced into the leaching environment [6]. The two sources of oxygen during cyanide heap leaching are dissolved oxygen (DO) in the feed solution and gaseous oxygen in the heap interspace [7].…”

Section: Introductionmentioning

confidence: 99%

Ozone Ice as an Oxygen Release Reagent for Heap Leaching of Gold Ore

et al. 2021

View full text Add to dashboard Cite

The issue of poor aeration efficiency and low oxygen transfer in the heap leaching of gold has gained considerable attention. In this study, ozone ice was studied as an oxygen release reagent in the cyanide heap leaching of gold at a low temperature of approximately 5 °C, owing to its effective oxidation and clean and green properties. Quartz Crystal Microbalance with Dissipation (QCM-D) was used to monitor the effect of different ratios of cyanide and oxygen concentrations on the gold leaching rate. The results showed that the leaching rate doubled when the dissolved oxygen (DO) was increased from 8.2 mg/L to 12 mg/L at a relatively high cyanide concentration of 60 mg/L. The release of oxygen during the process of ozone ice melting was analyzed by simulating the oxygen-deficient condition of the ore heap in column leaching. In the first stage of ice melting, the DO in the solution increased dramatically, and the rate of increase improved with increased initial ozone concentration in the ice. In the second stage of ice melting, the rate of increase in the DO of the solution was not significantly affected by the initial ozone concentration in the ice; this was consistent with the decomposition rate of ozone. The addition of ozone ice containing 300 mg/L ozone increased the gold extraction by 4.1% in the ore column leaching experiment, compared to a column with no ozone ice. However, continuously increasing the ozone concentration up to 600 mg/L had no further significant effect, because the dissolved oxygen in the leaching solution reached saturation. The results facilitate a better understanding of the decomposition law of ozone in the melting process of ozone ice and help to improve the oxygen deficit state in gold leaching heaps.

show abstract

Decomposition of hydrogen peroxide in alkaline cyanide solutions

Cited by 10 publications

References 11 publications

Repurposing of Fruit Peel Waste as a Green Reductant for Recycling of Spent Lithium-Ion Batteries

Repurposing of Fruit Peel Waste as a Green Reductant for Recycling of Spent Lithium-Ion Batteries

Photocatalytic Advanced Oxidation Processes for Neutralizing Free Cyanide in Gold Processing Effluents in Arequipa, Southern Peru

Ozone Ice as an Oxygen Release Reagent for Heap Leaching of Gold Ore

Contact Info

Product

Resources

About