Separation of Gold and Silver from Diverse Solutions by Solvent Extraction

행위동,이만승,Xing, Weidong,Lee, Manseung The Korean Institute of Resources Recycling 2017 資源 리싸이클링 Vol.26 No.5

금과 은은 귀금속으로 첨단소재를 제조하는데 사용된다. 용매추출은 다양한 침출용액으로 부터 순수한 금과 은을 회수할 수 있는 중요한 공정이다. 본 논문에서는 cyanide, thiocyanate, thiosulfate, thiourea과 염산용액에서 금(I, III)과 은(I)의 용액화학 및 용매추출에 의한 분리를 고찰했다. 여러 단독 및 혼합추출제에 의한 금(I, III)과 은(I)의 용매추출 및 분리거동을 각 침출용액에서 추출반응과 추출제의 선택도를 토대로 비교했다. 염산용액이 용매추출에 의한 금과 은의 분리의 효율측면에서 적당하다. Solvent extraction is an important process to recover pure gold and silver from various leaching solutions. The present work reviews the aqueous chemistry and solvent extraction separation of gold (I, III) and silver (I) from several leaching systems such as cyanide, thiocyanate, thiosulfate, thiourea and chloride medium. The extraction and separation behavior of gold (I, III) and silver (I) by various single and mixtures was compared on the basis of extraction reaction and the selectivity from these mediums. The chloride medium is recommended for the separation of gold and silver by solvent extraction in terms of extraction and stripping efficiency.

Leaching of gold and silver from anode slime with a mixture of hydrochloric acid and oxidizing agents

행위동,이만승 한국자원공학회 2017 Geosystem engineering Vol.20 No.4

In order to develop a hydrometallurgical process to recover gold and silver from anode slime resulted from the treatment of copper sludge, leaching experiments of the anode slime were performed by a mixture of HCl and some oxidizing agents (H2O2, NaClO, and HNO3). Effect of the concentration of oxidizing agents, reaction temperature and time, pulp density and stirring speed on the leaching of the metals in the anode slime (Au, Ag, Cu, Sn, Ni, and Zn) was investigated. According to the results, all the metals except silver were completely dissolved into the mixture of HCl and the oxidizing agents employed in this work. However, the leaching percentage of Ag was only 10% with the mixture of HCl and either H2O2 or NaClO, while 28% of Ag was dissolved into the mixture of HCl and HNO3. Complete dissolution of silver was difficult in the presence of chloride ion.

Separation of gold(III) from hydrochloric acid solution containing platinum(IV) and palladium(II) by solvent extraction with Cyanex 272 and LIX 63

행위동,이만승,김영환 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.59 No.-

Solvent extraction experiments were performed to separate Au(III), Pt(IV) and Pd(II) in the HCl concentration ranged from 0.5 to 9 M. Cyanex 272 extracted only Au(III) among the three metals, while both Au(III) and Pd(II) was extracted by LIX 63 in the experimental ranges. The Au(III) in the loaded Cyanex 272 and LIX63 was stripped by either (NH4)2S2O3 or (NH2)2CS. The concentration ratio of Au(III) to Pd(II) affected the extraction behavior of Au(III) and Pd(II) by LIX 63. The characteristic vibration bands of Cyanex 272 and LIX 63 were proposed by analyzing the FT-IR.

Treatment of Black Dross with Water and NaOH Solution

행위동,안병두,이만승,Xing, Wei Dong,Ahn, Byung Doo,Lee, Man Seung The Korean Institute of Resources Recycling 2017 資源 리싸이클링 Vol.26 No.3

블랙드로스에는 금속 알루미늄, 알루미나, 실리카, 산화마그네슘, 가용성 염 및 미량 성분이 함유되어 있다. 블랙드로스를 사용가능한 재료로 전환시키기 위해서는 실리카의 양을 조절하는 것이 중요하다. 먼저 가용성 염인 염화나트륨과 염화칼륨은 $50^{\circ}C$에서 물에 용해되었다. 물세척 후 잔사에 함유된 실리카, 알루미나, 산화마그네슘 및 산화타이타늄의 침출거동을 NaOH의 농도와 반응온도를 변화시키며 조사하였다. 반응온도 $25{\sim}95^{\circ}C$에서 알루미나의 침출율은 온도에 비례하나 실리카의 침출의 경우에는 최적 온도가 존재하였다. 한편 2~6 M의 NaOH용액에 산화마그네슘은 전혀 용해되지 않았다. 5 M의 NaOH와 $95^{\circ}C$에서 알루미나와 실리카의 침출율은 각각 80과 68%이었다. 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.

Recovery of gold(III) from the stripping solution containing palladium(II) by ion exchange and synthesis of gold particles

행위동,이만승 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.69 No.-

Separation of macro amount of gold(III) from a small amount of Pd(II) was investigated by ion exchange. From the screening experiments, a nonionic resin Amberlite XAD7HP was selected for this purpose. The adsorption behavior of Au(III) onto Amberlite XAD7HP followed Langmuir isotherm. The loading capacity obtained from the isotherm agreed well with that experimentally measured. Au(III) solution with 99.99% purity was obtained by eluting the loaded Amberlite XAD7HP with the mixture of HCl and acetone. Comparative studies on the synthesis of gold particles were done from the eluate by adding ascorbic acid and K2CO3 in presence and absence of acetone.

Leaching of the Mixture of Metallic Gold and Silver

행위동,이만승 한국자원리싸이클링학회 2017 資源 리싸이클링 Vol.26 No.2

In order to exclude the effect of uneven distribution of gold in anode slime, the dissolution of gold and silver from the metal mixture was investigated in different systems, such as the mixture of hydrochloric acid and oxidizing reagents (H 2 O 2 , NaClO and HNO 3 ), thiosulfate and thiourea. In the mixture of HCl and either HNO 3 or H 2 O 2 , Au was completely dissolved but the leaching percentage of Ag was around 1%. In both thiosulfate and thiourea solution, gold was not dissolved at all. The presence of ferric ion in acidic thiourea solution showed a favorable effect on the leaching of silver but further study is necessary to elucidate the combined effect of ferric ion and sulfuric acid.

Leaching of Gold and Silver from Anode Slime with Inorganic Reagents

행위동,이기웅,이만승 한국자원리싸이클링학회 2017 資源 리싸이클링 Vol.26 No.1

Leaching experiments of anode slime were performed with several inorganic acids (HCl, HNO 3 and H 2 SO 4 ) together with thiourea and thiosulfate solution to recover gold and silver. Gold was not dissolved at all into these inorganic acids in the absence of any oxidizing agents. At the same concentration of inorganic acid, the leaching of percentage of Ag was the highest in the sulfuric acid solution. The leaching percentage of silver increased with the increase of HCl concentration owing to the formation of AgCl 2 − . Copper, nickel and zinc except tin was almost dissolved in these inorganic acids but no tin was dissolved in nitric acid solution. Most of Au and Ag were dissolved into the mixture of sulfuric acid and thiourea solution. Thiosulfate could dissolve some silver from the anode slime but no gold was dissolved by this agent.

Chemical Leaching of Silver from Diverse Resources

행위동,이만승 한국자원리싸이클링학회 2017 資源 리싸이클링 Vol.26 No.1

The special properties of silver are often indispensable in the manufacture of advanced materials. Therefore, it is of importance to develop a process to recover silver which is necessary for the production of advanced materials from diverse resources. In this manuscript, the developed processes for the leaching of silver from diverse resources are reviewed. For this purpose, the advantages and disadvantages of using some inorganic acids (nitric and sulfuric acid) and their mixture with other oxidizing agents (ozone, oxygen, hydrogen peroxide and ferric ion) were investigated. Moreover, the leaching of silver with thiourea and thiosulfate was compared over those by inorganic acids in terms of environmental effect.

FeCl₃를 함유한 중성추출제의 혼합용매로 약한 염산용액으로부터 리튬(I)의 용매추출

행위동,이세아,이만승,Xing, Weidong,Lee, Seah,Lee, Manseung The Korean Institute of Resources Recycling 2018 資源 리싸이클링 Vol.27 No.6

Solvent extraction of Li(I) from weak HCl solution was investigated by the mixture of TBP/MIBK with other neutral extractants such as Cyanex 923, TOPO and TOP. The TBP/MIBK organic phase was loaded with 0.1 M $FeCl_3$ at different HCl concentrations (1-9 M). Extraction of Li(I) from weak HCl solution is related to the stability of $FeCl_3$ in the organic mixture. As HCl concentration increased in preparing the loaded TBP phase, the stripping percentage of Fe(III) during the extraction of Li(I) became reduced and thus Li(I) could be extracted by ion exchange reaction with hydrogen ion in the organic. The concentration of TBP in the extractant mixture affected the stability of $FeCl_3$. Compared to TBP, Fe(III) was easily stripped from the loaded MIBK and thus no Li(I) was extracted by the mixture with MIBK. The nature of neutral extractant with TBP/MIBK showed little difference in the extraction of Li(I) and stripping of Fe(III).