• Resources Recycling
• /
• v.22 no.2
• /
• pp.44-52
• /
• 2013

Bioleaching behavior of metal ions for recovery of cobalt and copper from cobalt concentrate was investigated by employing three Aspergillus niger strains. Various factors, such as organic acid generation with fungi type, pH of the culture and pulp density were studied. The results showed that the best fungi for organic acid(citric acid and oxalic acid) generation was A. niger KCTC 6144 using Malt Extract Broth culture at initial pH 3.5. But A. niger KCTC 6985 was more effective for the leaching of cobalt and copper from cobalt concentrate. Our results showed that 82% cobalt and 98% copper was dissolved by A. niger KCTC 6985 at 10g/L pulp density, at pH 3.5 and $24^{\circ}C$ after 15 days incubation.

• Resources Recycling
• /
• v.25 no.2
• /
• pp.25-32
• /
• 2016

A electrodeposion behavior of tin was tested to recovery of tin metal from sulfate solution using a newly designed cyclone type electrolyzer. Parameters, such as flow rate, current density, tin and sulfuric acid concentration in the electrolyte were investigated. From the experimental results, a powered tin metal below $100{\mu}m$ can be obtained. As the increase of flow rate, current density and sulfuric acid concentration in the electrolyte, electrodeposition ratio of tin and current efficiency were increased. The electrodeposition ratio of tin was increased with the decrease of tin concentration in the electrolyte, but the current efficiency was decreased.

• Resources Recycling
• /
• v.17 no.3
• /
• pp.42-47
• /
• 2008

In this work, the dissolution behavior of Pb from the complex sulphide concentrates containing Galena and Arsenopyrite by alkaline oxidative leaching was studied. The influences of leaching temperature, oxygen partial pressure, leaching time and NaOH concentration of leaching solution were examined at the leaching conditions in the range of $100^{\circ}C{\sim}140^{\circ}C$ temperature, $40psi{\sim}100psi\;PO_2$ and $0.5M{\sim}2M$ NaOH concentration. The optimum result was obtained at the leaching condition of leaching temperature $120^{\circ}C$, 100psi $PO_2$, leaching time 30min. and 2M NaOH concentration of leaching solution.

• Resources Recycling
• /
• v.26 no.3
• /
• pp.53-60
• /
• 2017

Black dross contains metallic aluminium, alumina, silica, MgO, soluble salts together with minor ingredients. Control of silica in black dross is important in transforming the black dross into usable materials. First, most of the soluble salts (KCl and NaCl) in black dross were dissolved in water at reaction temperature of $50^{\circ}C$. Leaching behavior of silica, alumina, MgO and $TiO_2$ from the residue after water treatment was investigated by varying NaOH concentration and reaction temperature. Reaction temperature ($25{\sim}95^{\circ}C$) was favorable to the leaching of alumina but an optimum temperature existed for silica. MgO was not dissolved at all in the NaOH concentration range from 2 to 6 M. At the leaching condition of 5 M NaOH and reaction temperature of $95^{\circ}C$, approximately 80% of alumina and 68% of silica was dissolved.

• Resources Recycling
• /
• v.26 no.6
• /
• pp.58-64
• /
• 2017

Leaching of black dross with HCl solution was conducted to find a suitable process to recover valauble materials. In this work, the leaching behavior of the components was compared between black dross and the residues after water treatment. All the components except $TiO_2$ in the black dross were dissolved by HCl solution in the experimental ranges. Treatment of the black dross with water to recover the salts has negative effect on the leaching of $Al_2O_3$, MgO and $SiO_2$. The reactions occuring during the leaching were discussed. At an optimum leaching condition of 3 M HCl and $90^{\circ}C$, the leaching percentage of $Al_2O_3$, MgO and $SiO_2$ was 85, 100 and 40%, respectively.

• Resources Recycling
• /
• v.21 no.6
• /
• pp.32-38
• /
• 2012

In this study, direct reduction of $ZrO_2$ using liquid calcium was investigated. The influence of molar ratio of Ca and $ZrO_2$, reaction time and temperature on the reduction behavior of $ZrO_2$ was studied. Experiments were conducted in a closed stainless steel chamber under Ar atmosphere during 5 to 60 minutes. Most of the $ZrO_2$ was reduced to Zr in 5 minutes at 1223 K and 3 Ca/$ZrO_2$ molar ratio. The minimum oxygen content in reduced metal Zr was obtained about 0.66 wt% at 1373 K after 30 minutes and 4 Ca/$ZrO_2$ molar ratio. The morphology of zirconium powder obtained was highly affected by the reaction temperature and reaction time.

• Resources Recycling
• /
• v.14 no.6 s.68
• /
• pp.60-63
• /
• 2005

It was possible to understand the adsorption characteristics of ions in aqueous environment based on the variations of PZC and IEP of particles when adsorption of ions on particle surface occurred. The specific adsorption of $Cu^{2+}$ ion upon chalcopyrite surface provoked a lowered PZC, which was considered to be due to increased adsorption of OH- ion via the electrostatic attraction between the two ions. On the contrary, IEP of chalcopyrite was observed to rise when Cu2+ was specifically adsorbed on its surface. The reason for this could be explained by the necessity of the increase of pH to offset the positively increased surface potential of chalcopyrite for the reestablishment of IEP. Neither PZC or IEP of chalcopyrite was observed to change when non-specific adsorption occurred since no change in the surface potential of chalcopyrite was invoked under this condition.

• Resources Recycling
• /
• v.9 no.4
• /
• pp.3-15
• /
• 2000

Reduction of Electric Arc Furnace dust with carbon (graphite) was studied at the temperature range of $800^{\circ}C$ to $1100^{\circ}C$ in Ar gas atmosphere. The briquetted dust with graphite powder was heated in a vertical tube furnace for given reaction time and Quenched in Ar gas atmosphere. It was found that initially the reduction of Zn was chemically controlled and the activation energy was about 120 KJ/mole. Because the almost all of Pb was removed with Cl in the form of $PbCl_2$, it is considered that Pb is removed by chloride reduction. Cu was vaporized as a chloride up to 30% of its original content, but the remaining of Cu would be accumulated with the reduced iron. and also, Cd was removed completely within 15 min. at $1000^{\circ}C$.

• Resources Recycling
• /
• v.9 no.4
• /
• pp.37-43
• /
• 2000

Leaching of $LiCoO_2$ as a cathodic active materials for recovering Li and Co from spent lithium ion battery was investigated in terms of reaction variables. At the optimum condition determined in the previous work, Li and Co in a $H_2SO_4$ and $HNO_3$ solution were dissolved 70~80% and 40%, respectively. Li and Co were leached over 95% with the addition of a reductant such as $Na_2S_2O_3$ or $H_2O_2$. This behavior is probably due to the reduction of $Co^{3+}$ to $Co^{2+}$. Leaching of $LiCoCo_2$ powder obtained by calcination of an electrode materials from spent batteries was also carried out. Leaching efficiency of Li and Co were over 99% at the optimum condition with $H_2O_2$ addition of 1.7 vol.%. It seems to be due to the activation of $LiCoO_2$ by repeated charging and discharging or an imperfect crystal structure by deintercalation of Li.

• Resources Recycling
• /
• v.8 no.5
• /
• pp.44-50
• /
• 1999

The sbdy iwestlgaled ihc propa-ties of Lhe dust\ulcorner rrom fe~~oallomya ~~ufacturTeh. e chemical composition, cornpasitlon material, p d c l e sire md shapes of the bulk dust, sired dust and magnetically separated durl were mvesligaled. As the re\ulcornerulL, we suppose that the dust from &gh Carbon Fenama~~gunesMc anuiact~vingP rocess is not sufiicient as solulce material of Mn because of ale low Mn canlenl (13.5%) and complicaled composition mate~ial. The dust from Bug F!lter or AOD Proccss is mi~inlym ade up of 0.2-2 pm Mn30, (Hausmam~iu)p iutlde in spherical shape and thc Mn content is 63.190.The dust from Cooler of AOD Process is inninly made up of coarse Ca(O1-Or)zM. n,FeyO,, SiO, and fine Mn30d.