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

Minerals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1251
Author(s):  
Ziyuan Liu ◽  
Jue Kou ◽  
Yi Xing ◽  
Chunbao Sun ◽  
Peng Liu ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
Ozone Concentration ◽  
Heap Leaching ◽  
Oxygen Deficit ◽  
Leaching Rate ◽  
Oxygen Release ◽  
Ice Melting ◽  
Gold Leaching ◽  
Column Leaching ◽  
Rate Of Increase

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.

Methods for studying dissolved oxygen levels in coastal and estuarine waters receiving combined sewer overflows

1995 ◽  
Vol 32 (2) ◽  
pp. 95-103
Author(s):  
José A. Revilla ◽  
Kalin N. Koev ◽  
Rafael Díaz ◽  
César Álvarez ◽  
Antonio Roldán
Keyword(s):  
Dissolved Oxygen ◽  
Coastal Waters ◽  
Computational Cost ◽  
Oxygen Deficit ◽  
Alternative Methods ◽  
Coastal Zones ◽  
Combined Sewer Overflows ◽  
Sewer Systems ◽  
Combined Sewer ◽  
High Computational Cost

One factor in determining the transport capacity of coastal interceptors in Combined Sewer Systems (CSS) is the reduction of Dissolved Oxygen (DO) in coastal waters originating from the overflows. The study of the evolution of DO in coastal zones is complex. The high computational cost of using mathematical models discriminates against the required probabilistic analysis being undertaken. Alternative methods, based on such mathematical modelling, employed in a limited number of cases, are therefore needed. In this paper two alternative methods are presented for the study of oxygen deficit resulting from overflows of CSS. In the first, statistical analyses focus on the causes of the deficit (the volume discharged). The second concentrates on the effects (the concentrations of oxygen in the sea). Both methods have been applied in a study of the coastal interceptor at Pasajes Estuary (Guipúzcoa, Spain) with similar results.

scholarly journals Influence of grain size on chalcopyrite ore leaching in acidic medium

2007 ◽  
Vol 72 (8-9) ◽  
pp. 911-919 ◽  
Author(s):  
M.M. Antonijevic ◽  
G.D. Bogdanovic ◽  
S.M. Serbula ◽  
S.M. Milic
Keyword(s):  
Grain Size ◽  
Dissolved Oxygen ◽  
Sulphuric Acid ◽  
Acidic Medium ◽  
Raw Material ◽  
Leaching Rate ◽  
Acid Consumption ◽  
Leaching Solution ◽  
Chalcopyrite Ore

This work presents an investigation of column leaching of a chalcopyrite ore using sulphuric acid where dissolved oxygen and iron(III) ions play the role of oxidants. The investigations were carried out in PVC columns, diameter 110 mm and height 1000 mm, by percolation of the leaching solution through the ore layer. The influence of ore grain size on the degree of leaching and acid consumption was examined. The formation of gypsum on limestone results in the comminution of the initial raw material during leaching. The grain size of chalcopyrite was found to have no important influence on the leaching rate of copper. A higher consumption of sulphuric acid was found for the fractions (-3+1) mm, (?5+0) mm and (?5+3) mm than for the fractions (?10+5) mm, (?20+10) mm and (?20+0) mm. .

Coupling Flow-Reaction-Transmission during Square Column Leaching Processes

2013 ◽  
Vol 734-737 ◽  
pp. 698-702
Author(s):  
Jin Zhi Liu ◽  
Yu Hang Li ◽  
Bao Hua Yang
Keyword(s):  
Numerical Simulation ◽  
Hydraulic Conductivity ◽  
Leaching Rate ◽  
Analysis Software ◽  
Copper Ore ◽  
Column Leaching ◽  
Changing Trends ◽  
Copper Leaching ◽  
Leaching Experiment ◽  
Flow Reaction

This paper designs a square column leaching experiment to probe the coupling flow-reaction-transmission. 2.372 kg of Yanglas copper ore with a grade of 1.25% was loaded in a 6×6 cm2 column whose height is 60 cm. A 28-day leaching gave an approximate copper yield of 14.5 gram, which is an equivalence of copper leaching rate being 50%. Hydraulic conductivity was measured. The changing trends are analyzed by mathematical analysis software Eviews and Matlab, and the numerical simulation was conducted.

Use of the water quality index and dissolved oxygen deficit as simple indicators of watersheds pollution

2007 ◽  
Vol 7 (2) ◽  
pp. 315-328 ◽  
Author(s):  
Enrique Sánchez ◽  
Manuel F. Colmenarejo ◽  
Juan Vicente ◽  
Angel Rubio ◽  
María G. García ◽  
...  
Keyword(s):  
Water Quality ◽  
Dissolved Oxygen ◽  
Water Quality Index ◽  
Quality Index ◽  
Oxygen Deficit

scholarly journals DAYA TAMPUNG SUNGAI REMBAGAN TERHADAP BEBAN PENCEMARAN MENGGUNAKAN METODE STREETER-PHELPS

2021 ◽  
Vol 10 (2) ◽  
pp. 209
Author(s):  
Sri Wahyuningsih ◽  
Elida Novita ◽  
Irfan Dwi Satya
Keyword(s):  
Water Quality ◽  
Dissolved Oxygen ◽  
Agricultural Waste ◽  
Oxygen Deficit ◽  
Research Needs ◽  
Agricultural Activities ◽  
Class Iii ◽  
Pollution Load ◽  
Community Activities

Rembagan River is the main tributary of the Bedadung River in Cangkring Village, Patrang District, Jember Region. Various community activities in the Rembagan River area such as bathing, washing, defecating and urinating as well as agricultural activities will produce domestic and agricultural waste. These wast can cause river water pollution, especially water quality degradation. then the research needs to be done an analysis of the capacity of the Rembagan River in receiving pollution costs. The purpose of this study is to find out how much the ability of the Rembagan River to accept the burden of pollutants using the Streeter-Phelps method. Streeter-Phelps modeling takes into account two phenomena, namely the process of measuring dissolved oxygen (deoxygenation) and the process of increasing dissolved oxygen (reaeration). The results obtained from these calculations are oxygen drop curves determined on the basis of oxygen deficit values. The average values of deoxygenation rate and reoxygenation rate were sequentially 1.58931 mg/L/day and 10.09982 mg/L/day. So that self-purification can run well which means the water quality of the Rembagan River was still relatively good. This can be seen in the DO model pattern that goes up in each segment. The actual DO of 5.6760 mg / L was greater than the DO standard of class III quality of 3 mg / L. It can be interpreted that the Rembagan River still has a remaining DO of 2.676 mg / L and was still able to accept pollution cost of 18.8 kg/day. Keywords:  pollution load, Rembagan River, river capacity

Study on the Gold Leaching Process by Potassium Ferricyanide

2015 ◽  
Vol 814 ◽  
pp. 273-277
Author(s):  
Ping Tang ◽  
Jing Liu ◽  
Min Wei Song ◽  
Hai Ping Yu ◽  
Xu Zhang
Keyword(s):  
Room Temperature ◽  
Potassium Ferricyanide ◽  
Process Conditions ◽  
Leaching Rate ◽  
Gold Leaching ◽  
Solid Ratio ◽  
Leaching Process ◽  
Refractory Gold ◽  
Object Of Study ◽  
High Arsenic

The traditional gold leaching method is cyanidation, which carries serious security and environmental problems. More and more attention is paid to the research on non-cyanide process. A high-arsenic-and-sulphur refractory gold concentrate in Sichuan was taken as the object of study. After the roasting-oxidation pretreatment of the sample, potassium ferricyanide was adopted to carry on the process experiment on gold-leaching. The leaching results as well as correlative process conditions were both investigated. The results showed that good leaching effects could be achieved by potassium ferricyanide. When the amount of potassium ferricyanide was 60g/L, the concentration of NaOH 0.2mol/L, the liquid-solid ratio 6:1 and the leaching process at room temperature lasted for 20h, the gold leaching rate reached 88.1%. If the leaching aid CaO2 is added simultaneously, it can contribute to the gold leaching. When the amount of CaO2 was 3g/L, the gold leaching rate increased to more than 94%, the amount of potassium ferricyanide decreased to 50g/L and the leaching time reduced to 14h.

Column Bioleaching of Low Grade Copper Sulfide Ore at Extreme Conditions for Most Mineral Processing Bacteria

2013 ◽  
Vol 825 ◽  
pp. 318-321 ◽  
Author(s):  
Gang Zou ◽  
Zeng Ling Wu ◽  
Xiao Kang Lai ◽  
Lai Chang Zou ◽  
Ren Man Ruan ◽  
...  
Keyword(s):  
Iron Concentration ◽  
Heap Leaching ◽  
Operating Conditions ◽  
Industrial Plant ◽  
Copper Extraction ◽  
Low Grade ◽  
Extreme Conditions ◽  
Leaching Rate ◽  
Copper Leaching ◽  
Leaching Efficiency

This study is prompted by the high leaching efficiency of Zijinshan copper bio-heap leaching industrial plant. Bioleaching columns with 100 mm diameter and 1 m height were used to investigate copper bioleaching at different operating conditions. Elevated temperature, high total iron concentration and high acidity significantly increased copper leaching rate as determined by solution and residue assays. At 60 °C with 50 g/L iron (initial Fe3+/Fe2+ gram ratio 2.5), pH 1.0 and no aeration, copper extraction was achieved 90% after 60 days. However, at 30°C, 5 g/L total Fe, pH 1.5 and no aeration, copper extraction reached 80% and 85% after 90 and 200 days, respectively. Real-time PCR assay showed that only 105 cells/ml and 2×105 cells/g are in solution and on the ore surface at the condition of 60 °C 50 g/L iron and pH 1.0, respectively. In addition, a similar leaching rate was observed in the tests with and without inoculation. The column without inoculation was directly irrigated with acid mine drainage (AMD). Our results indicate high copper leaching efficiency at extreme conditions for mineral oxidizing bacteria. Inoculation and aeration are not necessary in Zijinshan copper mine bio-heap leaching process.

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