Claim Missing Document
Check
Articles

Found 4 Documents
Search

BIOLEACHING OF LOW GRADE NICKEL ORE USING INDIGENOUS FUNGI Sri Handayani; Suratman Suratman
Indonesian Mining Journal Vol 19, No 3 (2016): INDONESIAN MINING JOURNAL VOL. 19 NO. 3, October 2016
Publisher : Puslitbang tekMIRA

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (676.716 KB) | DOI: 10.30556/imj.Vol19.No3.2016.540

Abstract

In this research, the biological leaching of nickel by indigenous fungi isolated from Indonesian limonite was studied to develop a feasible technique for microbial recovery of nickel from low grade nickel ore. XRD analyses indicated that goethite, alumina and quartz were major mineral composition of the ore. In the present study, isolated fungal strains having potential to solubilize nickel were characterized. that were identified as Aspergillus sp and Penicillium sp depending upon their colony morphology and microscopic studies. All microorganisms found were tested for organic acid production and leaching capabilities of nickel. Leaching experiments were performed in 250 ml Erlenmeyer flask at room temperature and 150 rpm agitation under aseptic conditions. It was observed that the Aspergillus sp substantially leached more nickel from limonite compared to the Penicillium sp. Nickel solubilization was related to pH decrease and organic acid excreted caused by growth of fungi in medium containing glucose as carbon source. The mechanisms of nickel extraction had been examined either directly or indirectly related to fungal activity. The presence of fungal cells seems to improve the leaching process. However, the use of higher pulp density resulted in a decrease of nickel solubilization. The maximum nickel recovery was 57% at 5% pulp density after 20 days of direct leaching by Aspergillus sp.
GOLD RECOVERY OF REFRACTORY SULFIDE CONCENTRATES USING DIRECT CYANIDE LEACHING WITH NITRITE AS AN OXIDANT Suratman Suratman
Indonesian Mining Journal Vol 19, No 3 (2016): INDONESIAN MINING JOURNAL VOL. 19 NO. 3, October 2016
Publisher : Puslitbang tekMIRA

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (771.565 KB) | DOI: 10.30556/imj.Vol19.No3.2016.541

Abstract

The problem of refractory sulfide gold ore that has a gold recovery less than 50% when direct cyanidation applied, still exists until now. It needs oxidative pretreatment for cyanidation to be effective in gold recovery the objective of this study is figuring out the effect of sodium nitrite as an oxidizing reagent on cyanidation of refractory gold ore. Cyanide leaching of the concentrate was performed at 20%-w/w of solid (500 gram of refractory sulfide gold ore concentrate) in a 2.5-liter glass reactor with aeration and stirred at 250 rpm. Leach solutions were prepared using deionized-distilled water at the prescribed concentration of reagents. Recovery of gold increased gradually to its maximum value of 93.05% as the value of cyanide strength increased from 0.8 to 1.2% and the addition of sodium nitrite raise to 1.2 M. No improvement for further addition of nitrites. This introduction of new hydrometallurgical pre-treatment process has given more option for treating refractory ores.
BIOLEACHING OF LOW GRADE NICKEL ORE USING INDIGENOUS FUNGI Sri Handayani; Suratman Suratman
Indonesian Mining Journal Vol 19 No 3 (2016): INDONESIAN MINING JOURNAL VOL. 19 NO. 3, October 2016
Publisher : Balai Besar Pengujian Mineral dan Batubara tekMIRA

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30556/imj.Vol19.No3.2016.540

Abstract

In this research, the biological leaching of nickel by indigenous fungi isolated from Indonesian limonite was studied to develop a feasible technique for microbial recovery of nickel from low grade nickel ore. XRD analyses indicated that goethite, alumina and quartz were major mineral composition of the ore. In the present study, isolated fungal strains having potential to solubilize nickel were characterized. that were identified as Aspergillus sp and Penicillium sp depending upon their colony morphology and microscopic studies. All microorganisms found were tested for organic acid production and leaching capabilities of nickel. Leaching experiments were performed in 250 ml Erlenmeyer flask at room temperature and 150 rpm agitation under aseptic conditions. It was observed that the Aspergillus sp substantially leached more nickel from limonite compared to the Penicillium sp. Nickel solubilization was related to pH decrease and organic acid excreted caused by growth of fungi in medium containing glucose as carbon source. The mechanisms of nickel extraction had been examined either directly or indirectly related to fungal activity. The presence of fungal cells seems to improve the leaching process. However, the use of higher pulp density resulted in a decrease of nickel solubilization. The maximum nickel recovery was 57% at 5% pulp density after 20 days of direct leaching by Aspergillus sp.
GOLD RECOVERY OF REFRACTORY SULFIDE CONCENTRATES USING DIRECT CYANIDE LEACHING WITH NITRITE AS AN OXIDANT Suratman Suratman
Indonesian Mining Journal Vol 19 No 3 (2016): INDONESIAN MINING JOURNAL VOL. 19 NO. 3, October 2016
Publisher : Balai Besar Pengujian Mineral dan Batubara tekMIRA

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30556/imj.Vol19.No3.2016.541

Abstract

The problem of refractory sulfide gold ore that has a gold recovery less than 50% when direct cyanidation applied, still exists until now. It needs oxidative pretreatment for cyanidation to be effective in gold recovery the objective of this study is figuring out the effect of sodium nitrite as an oxidizing reagent on cyanidation of refractory gold ore. Cyanide leaching of the concentrate was performed at 20%-w/w of solid (500 gram of refractory sulfide gold ore concentrate) in a 2.5-liter glass reactor with aeration and stirred at 250 rpm. Leach solutions were prepared using deionized-distilled water at the prescribed concentration of reagents. Recovery of gold increased gradually to its maximum value of 93.05% as the value of cyanide strength increased from 0.8 to 1.2% and the addition of sodium nitrite raise to 1.2 M. No improvement for further addition of nitrites. This introduction of new hydrometallurgical pre-treatment process has given more option for treating refractory ores.