is used to extract precious metals like silver and gold by converting these metals or their ores into their soluble complexes by the process called as leaching. In this process, the finely powdered argentite or silver is treated with a dilute solution of sodium cyanide while a current of air is continuously passed.
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Extraction of Silver. In the extraction of gold and silver, the metal is leached with NaCN or KCN, which is an oxidation reaction. During the process, Ag is oxidised to Ag + Here M =Ag or Au. Subsequent reaction with Zn leads to formation of free metal.
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NaCN in the extraction of gold from gold ore: In the metallurgy of gold, gold metal is leached with a dilute solution of NaCN in the presence of air (for O2). The gold metal is then obtained from the product by displacement reaction.
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(i) The roasted ore of gold is leached with a solution of sodium cyanide in the presence of oxygen for many days. The role of NaCN in this process is to dissolve the gold to form an aurocyanide complex, from which the metal is obtained by displacement. 4Au + 8NaCN + 2H2O + O2 ---> 4 Na [Au(CN)2] + 4KOH 2Na[Au(CN)2] + Zn ---> Na2[Zn(CN)4] + 2Au (ii) Copper matte contains Cu2S and FeS.
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Best answer. (i) NaCN is used in the leaching of argentite (Ag2S). Argentite is leached with dilute aqueous solution of NaCN in the presence of air. Ag 2 S + 4NaCN 2Na [Ag (CN) 2] + Na 2 S. (ii) Iodine in the refining of titanium. The crude metal is heated with iodine in an evacuated vessel to form volatile compound.
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The in- crease in the concentration of protective alkali (Ca (OH)2) increases the silver extraction and decreases the NaCN consumption, because it hinders the hydrol- 364 N. Acarkan et al. / Hydrometallurgy 36 (1994) 361-367 70L ~. 60! b ~ E Z 50 x ~ 40~ o 24 h [] 48 h -"0 3000~lJ ,i ,IL ,tlL ,~1 iii ijt iJ ilkllt i i J, 5~0 ~1 ~OI.
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The researchers found that increasing the cyanide concentration enhanced the silver extraction i.e. the silver content in the tailings were 61.6 and 50.5 g/t at 0.5 and 2 g/L NaCN, respectively. ...
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(i) The roasted ore of gold is leached with a solution of sodium cyanide in the presence of oxygen for many days. The role of NaCN in this process is to dissolve the gold to form an aurocyanide complex, from which the metal is obtained by displacement. 4Au + 8NaCN + 2H2O + O2 ---> 4 Na [Au(CN)2] + 4KOH 2Na[Au(CN)2] + Zn ---> Na2[Zn(CN)4] + 2Au (ii) Copper matte contains Cu2S and FeS.
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Extraction of Silver. In the extraction of gold and silver, the metal is leached with NaCN or KCN, which is an oxidation reaction. During the process, Ag is oxidised to Ag + Here M =Ag or Au. Subsequent reaction with Zn leads to formation of free metal.
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There is currently mch interest in how extraction of gold and silver from ores with acidic thiourea solution compares with extraction using alkaline cyanide solution. Agitation leaching tests were performed by the Bureau of Mines on 14 precious metal ores using sodium cyanide (NaCN) and thiourea [(NH2)2CS] as extractants.
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Extraction of Silver. Role of NaCN or KCN = In the extraction of gold and silver, the metal is leached with NaCN or KCN, which is an oxidation reaction. During the process, Ag is oxidised to Ag + . Here M =Ag or Au. Subsequent reaction with Zn leads to formation of free metal.
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Sequence the following steps involved generally in the extraction of a metal in pure form from its ore, the extraction of a metal in pure form from its ore. <br> (1) The metal obtained from its oxide requires further purification for end use. <br> (2) The ore shoud be converted to its oxide form. <br> (3) The ore is beneficial to us if it is hand-picked then metal crushed and ground, and later ...
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Write the role of dilute NaCN in the extraction of silver. Answer NaCN oxidises silver to form soluble complex of cyanide while the impurities remain unaffected which are filtered off.
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The in- crease in the concentration of protective alkali (Ca (OH)2) increases the silver extraction and decreases the NaCN consumption, because it hinders the hydrol- 364 N. Acarkan et al. / Hydrometallurgy 36 (1994) 361-367 70L ~. 60! b ~ E Z 50 x ~ 40~ o 24 h [] 48 h -"0 3000~lJ ,i ,IL ,tlL ,~1 iii ijt iJ ilkllt i i J, 5~0 ~1 ~OI.
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Describe role of NaCN in extraction of silver from silver ore Answers : 4Extraction of SilverRole of NaCN or KCN = In the extraction of gold and silver, the metal is leached with NaCN or KCN, which is an oxidation reaction.During the process, Ag is oxidised to Ag+ .Here M =Ag or Au.Subsequent reaction with Zn leads to formation of free metal.
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I) In the extraction of gold and silver the metal is leached with NaCN and KCN, which is a oxidation reaction. 4 M + 8 C N + 2 H 2 O + O 2 4 [ M ( C N ) 2 ] + 4 O H In the next step, the compound is reacted with zinc leading to the formation of metal.
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Role of NaCN in the extraction of silver (Ag) is to do the leaching of Ag ore in the presence of air from which the silver is obtained later by replacement. 4Ag + 8CN-+ 2H 2 O + O 2 4 [Ag(CN) 2-] + 4OH-Answered on: 2017/01/25 by ExamFear
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Answer. I) In the extraction of gold and silver the metal is leached with NaCN and KCN, which is a oxidation reaction. In the next step, the compound is reacted with zinc leading to the formation of metal. M is Ag or Au. ) in the extraction of copper is to remove the FeO obtained in roasting. So, silica is added before roasting as flux to remove iron impurity.
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Finally, the variance analysis at a level of 95% confidence shows that the variables studied significantly influence the extraction of gold and is presented as an alternative to the use of NaCN ...
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NaCn is use for leaching of Ag ore in the presence of air from which the silver is obtained later by replacement. Answer: To convert the silver ore into its soluble complex. The Brain
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Sequence the following steps involved generally in the extraction of a metal in pure form from its ore, the extraction of a metal in pure form from its ore. <br> (1) The metal obtained from its oxide requires further purification for end use. <br> (2) The ore shoud be converted to its oxide form. <br> (3) The ore is beneficial to us if it is hand-picked then metal crushed and ground, and later ...
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If NaCN concentration increased to 5 g/L, silver extraction increased up to 55% after reaching equilibrium. However, with the addition of only 0.05 g/L Fe(III) as ferricyanide to the 0.5 g/L NaCN solution, though without the presence of oxygen, silver extraction increased to more than 50% after leaching 8 h.
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Gaspirrini, in a study of the mineralogy of silver and its significance in metal extraction, including that by NaCN solutions, found that factors affecting the metallurgy of silver are (1) the silver-bearing minerals, (2) their grain size, (3) their host minerals, and (4) the association of the host minerals with the silver-bearing minerals.
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