Rendering wastes obtained from gold analysis by the lead-fusion fire-assay method non-hazardous

Magalhães, Fernanda Batalha; Carvalho, Cornélio de Freitas; Carvalho, Eduardo Lyse Corrêa Netto; Yoshida, María Irene; dos-Santos, Cláudio G.

doi:10.1016/j.jenvman.2012.06.028

Cited by 7 publications

(3 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In a previous work (Magalhães et al, 2012), we found that 0.09% of PbO by weight was incorporated into the crucible waste, which was also classified as hazardous, according to the limits established by Norm ABNT NBR 10004 (ABNT, 2004a). After extraction of such waste with hydrochloric and nitric acids followed by chemical precipitation with sodium metasilicate solution, 99.9% (w/w) of lead was recovered, rendering the ultimate waste non-hazardous.…”

Section: Discussionmentioning

confidence: 99%

Recovering lead from cupel waste generated in gold analysis by Pb-Fire assay

Cerceau

Carvalho

Rabêlo

et al. 2016

Journal of Environmental Management

View full text Add to dashboard Cite

Because of its precision and accuracy, Pb-Fire assay is the most employed method for gold analysis in geological materials. At the second stage of the method, namely cupellation, lead is oxidized to PbO which is absorbed by the cupel, leading to metallic gold as a tiny bend at the bottom of the recipient. After cupellation, cupel becomes highly contaminated with lead, making its disposal a serious risk of environmental contamination. In the present work, a leaching process for removing lead from cupel waste is proposed, which allowed for removing 96% of PbO by weight. After a precipitation step, 92.0% of lead was recovered from leachates in the form of PbSO. Lead in the solid wastes left by the extraction was above the limit established by Brazilian legislation and these were classified as non-hazardous. Finally, secondary effluents generated after the precipitation step presented lead content more than twenty times lower than that of leachates from cupel waste. Tons of cupel waste are annually generated from gold analysis by Pb-Fire assay. Thus, the proposed method can contribute to prevent the discharge of high amounts of lead into the environment. Also, recovery of lead can help to partially meet the industrial demand for lead compounds.

show abstract

Section: Discussionmentioning

confidence: 99%

Recovering lead from cupel waste generated in gold analysis by Pb-Fire assay

Cerceau

Carvalho

Rabêlo

et al. 2016

Journal of Environmental Management

View full text Add to dashboard Cite

show abstract

“…The samples were analyzed at the Chemical Metallurgical Laboratory JV Metals, located in El Pache, Portovelo, Ecuador. The method used to determine the head grade (feet) of the mineral sample was the Fire Assay [31]. This method consists of melting the sample with reagents and fluxes to detect metals such as gold and silver.…”

Section: Sampling and Data Analysismentioning

confidence: 99%

Investigation of Gold Recovery and Mercury Losses in Whole Ore Amalgamation: Artisanal Gold Mining in Nambija, Ecuador

González-Vásquez,

García-Martínez,

Bolonio

2023

Minerals

View full text Add to dashboard Cite

Mercury is a highly toxic pollutant that can negatively affect human health and the environment; informal mining is one of the main sources of anthropogenic mercury release due to the separation or concentration by amalgamation that is still used to recover gold directly from ore. In the Nambija mining district, there is still informal mining based on practically no technical knowledge, which uses amalgamation as a processing technique for gold recovery. The production tasks that directly affect the handling of mercury during the in situ grinding–amalgamation process are monitored here. Experimental grinding tests were initially carried out in a “chancha” bar mill for a range of ore sizes and as a function of time; then, experimental tests were performed at the macro-level on grinding cycles in Chilean mills. Considering the characteristics of the ore mineral and the operation of the Chilean mills, it was determined that it is possible to reduce the Hg input to mill by up to 20% (at source). Experimental grinding–amalgamation tests were carried out at different times along with a grain size analysis of the ore; the recovery establishes the grinding time and the fraction in which the gold is extracted in a greater proportion, which affects the control of the amalgamation times. The mercury dosage used by the miners in the amalgamation process should be reduced, considering trials where there is better gold recovery and with the purpose of also reducing mercury losses; eventually, it is possible to jointly achieve an increase in gold recovery.

show abstract

“…However, PbFA is accompanied by significant occupational safety and health (OSH) 7 and waste disposal 8 concerns, which arise mostly from the large amounts of PbO required: up to tonnes per month in large commercial laboratories. Reagentless options such as neutron 9 and gamma 10 activation analyses have been used to quantify gold directly in ores but their application in commercial mineral assay laboratories is seldom practicable.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Sodium peroxide fusion for reliable determination of gold in ores and metallurgical samples

Daniel

Laird

Hefter

2017

International Journal of Mineral Processing

View full text Add to dashboard Cite

A protocol based on peroxide fusion has been developed for the determination of Au in metallurgical samples and ores covering a wide range of concentrations and diverse mineralogies. The quantity of Na 2 O 2 required was minimised, while maintaining lixiviant efficacy, by the use of mixed NaOH + Na 2 O 2 fluxes. The method was shown to be applicable to the determination of coarsely-particulate gold. Fusion cakes were dissolved in hydrochloric acid and then extracted using methylisobutylketone to provide concentrations appropriate for quantification by graphite furnace atomic absorption spectroscopy and to minimise interferences from dissolved salts. The protocol was tested on a variety of certified reference materials and produced results in excellent agreement (at Au concentrations ranging from 0.05 to 47 µg g -1 ) with the traditional lead fire assay method, while avoiding the health and safety issues associated with that technique. KeywordsGold, peroxide fusion, metallurgical samples, ores Highlights 3 to 5 bullet points (maximum 85 characters, including spaces, per bullet point) Peroxide fusion GFAAS method suitable for routine commercial lab analysis developed Results comparable to Pb fire assay over wide range of mineralogy and concentration Potential for gold losses critically evaluated and found to be minimal Addition of NaOH significantly reduces amount of Na 2 O 2 required

show abstract

Rendering wastes obtained from gold analysis by the lead-fusion fire-assay method non-hazardous

Cited by 7 publications

References 23 publications

Recovering lead from cupel waste generated in gold analysis by Pb-Fire assay

Recovering lead from cupel waste generated in gold analysis by Pb-Fire assay

Investigation of Gold Recovery and Mercury Losses in Whole Ore Amalgamation: Artisanal Gold Mining in Nambija, Ecuador

Sodium peroxide fusion for reliable determination of gold in ores and metallurgical samples

Contact Info

Product

Resources

About