Elimination Cyanide with Hydrogen Peroxide (H&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;2&lt;/sub&gt;) and Calcium Hypochlorite (Ca(OCl)&lt;sub&gt;2&lt;/sub&gt;) on Gold Mine Waste from North Luwu, South Sulawesi

Abstract The cyanidation process is the most common method applied for the extraction of gold and silver in the hydrometallurgy industry, in which, sodium cyanide is used as a leaching agent. Therefore, the wastewater of gold mines contains a wide variety of cyanide ions needing to be removed before these wastewaters can be discharged to the receiving environments. In this study, a fuzzy multi-attribute decision-making approach (Fuzzy Delphi AHP and Fuzzy TOPSIS) was used for selecting the best cyanide removal method from the wastewater of Muteh gold mine. According to the experts' opinion, three methods including calcium hypochlorite, hydrogen peroxide and sodium hypochlorite were selected as alternatives. Then, by introducing the criteria influencing decision making, including cyanide removal ability, cost of process, amount of material consumed, time, pH, ease of performance and safety, and performing separated experiments, the criteria for each of three methods were determined. Finally, sodium hypochlorite was proposed as the best method for eliminating cyanide from wastewater. It was found that the rank of methods was as sodium hypochlorite (0.517) > calcium hypochlorite (0.474) > hydrogen peroxide (0.463).

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Decomposition of Cyanide from Gold Leaching Tailingsby Using Sodium Metabisulphite and Hydrogen Peroxide

Advances in Materials Science and Engineering ◽

10.1155/2020/5640963 ◽

2020 ◽

Vol 2020 ◽

pp. 1-7

Author(s):

Dongzhuang Hou ◽

Lang Liu ◽

Qixing Yang ◽

Bo Zhang ◽

Huafu Qiu ◽

...

Keyword(s):

Hydrogen Peroxide ◽

Comparative Study ◽

Contact Time ◽

Synergetic Effect ◽

Economic Conditions ◽

Gold Mine ◽

Optimal Conditions ◽

Gold Leaching ◽

Sodium Metabisulphite ◽

To Come

Cyanidation is widely used by most gold mine worldwide and will remain prevail in years (or decades) to come, while cyanide is hazardous, toxic pollutants whose presence in wastewater and tailings can seriously affect human and its environment; hence, it is necessary to control these contaminants. The purpose of this study was to examine the effects through the investigation of changes in pH, concentration, and contact time, and the optimal conditions were obtained. It has been proven that the decomposition of cyanide in solution and tailings increased as the alkalinity in the presence of 0.5 g/L Na2S2O5. An increase in H2O2 (30%) concentration (from 1 to 4 mL/L) increased the decomposition in solution, while the effect on removing cyanide was better when pH was 9 than 8 and 10 in tailings. The cyanide in tailings decreased in the first 4 h and increased after 4 h. The effective and economic conditions for maximum decomposition of cyanide from leach tailings are first treated in 0.5 g/L Na2S2O5 at pH 10 for 3 hours and then 2 mL/L H2O2 (30%) is added to the tailings at pH 9 for 4 hours through comparative study. The findings provide the basis to optimize the decomposition of cyanide from gold leaching tailings in mining or backfilling by using the synergetic effect of Na2S2O5 and H2O2.

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The use of factor analysis and acid base accounting to probe the speciation of toxic metals in gold mine waste

Environmental Earth Sciences ◽

10.1007/s12665-020-8887-7 ◽

2020 ◽

Vol 79 (6) ◽

Author(s):

O. A. Abegunde ◽

C. Okujeni ◽

L. Petrik ◽

A. M. Siad ◽

G. Madzivire ◽

...

Keyword(s):

Factor Analysis ◽

Toxic Metals ◽

Mine Waste ◽

Gold Mine ◽

Acid Base ◽

Acid Base Accounting

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Oxidation of Aqueous Unsymmetrical Dimethylhydrazine by Calcium Hypochlorite or Hydrogen Peroxide/ Copper Sulfate

Analytical Letters ◽

10.1080/00032717908059785 ◽

1979 ◽

Vol 12 (9) ◽

pp. 1063-1074 ◽

Cited By ~ 7

Author(s):

Martin H. Mach ◽

Annette M. Baumgartner

Keyword(s):

Hydrogen Peroxide ◽

Copper Sulfate ◽

Calcium Hypochlorite ◽

Unsymmetrical Dimethylhydrazine

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Case Studies of Wetland Filtration of Mine Waste Water in Constructed and Naturally Occurring Systems in Northern Australia

Water Science & Technology ◽

10.2166/wst.1994.0205 ◽

1994 ◽

Vol 29 (4) ◽

pp. 257-265 ◽

Cited By ~ 24

Author(s):

B. N. Noller ◽

P. H. Woods ◽

B. J. Ross

Keyword(s):

Waste Water ◽

Case Studies ◽

Mine Waste ◽

Waste Rock ◽

Typha Domingensis ◽

Gold Mine ◽

Northern Australia ◽

Runoff Water ◽

Naturally Occurring ◽

Mine Sites

A problem common to mines operating in the tropics is the disposal of water, which may be alkaline, acidic, or contain toxic elements such as arsenic or cadmium. The availability of year-round water supply at many mine sites in Northern Australia, particularly from pit dewatering, together with the monsoonal climate, provide appropriate conditions for the formation of natural wetlands or establishment of artificial wetlands. Wetland species (particularly Typha spp.) flourish in the presence of flowing or shallow water from dewatering, and data collected from natural and experimental wetlands show reduction of metal concentrations by wetland filtration of mine waste water. The following case studies are considered:Constructed wetlands, used to remove uranium from waste rock runoff before release to an adjacent creek provide a means of “polishing” runoff water prior to discharge to the creek.Creek-Billabong systems with existing wetlands adjacent to mine sites adventitiously “filter” waters discharged from mine sites. Trace elements in dewatering water from a gold mine discharged into an oxbow show reduction of elemental concentrations downstream, compared to discharge water.Naturally generated wetlands at several Northern Territory mines have developed along channels for discharge of pit water, with ingress of Typha domingensis. Such wetlands, associated with dewatering, have been examined at four mines, some with acid mine drainage. Water quality measured after wetland treatments shows reductions in concentrations of various heavy metals and sulfate. Volunteer Typha domingensis grows and spreads in shallow flowing channels, providing an inherent “filtration” of the water.Natural swamplands are incorporated in the waste rock runoff management design of a new gold mine, to reduce potentially high arsenic levels in the waste water. Constructed and naturally occurring wetlands may be used in the treatment of most mine waste waters to achieve levels of constituents acceptable for discharge to the surrounding environment.

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