Extraction from Gold Ores - Mac Arthur Forrest Cyanide Process:
The extraction of gold from sulphide or telluride ore includes the steps shown below:
1) Crushing, grinding and concentration:
The gold ore is at first crushed and powdered, and concentrated by froth-floatation procedure.2) Roasting:
The concentrated ore is roasted in surplus of air or oxygen whenever impurities of arsenic, sulphur, and tellurium are oxidised and escape as their volatile oxides.3) Treatment with KCN:
The finely powdered roasted ore is carried in large vats made up of cement or iron and containing false wooden bottoms with holes. It is then treated with a dilute 0.5 percent solution of KCN in the presence of excess of air for 24 hours. As an outcome, gold dissolves in KCN to provide a soluble complex termed as potassium aurocyanide.
4Au + 8KCN + 2H2O + O2 → 4K[Au(CN)2] + 4KOH Pot. aurocyanide4) Precipitation of gold:
The above solution having potassium aurocyanide is filtered to eliminate insoluble impurities and then treated with zinc dust. Gold being low electropositive than zinc, it acquires precipitated.
2K [Au (CN2] + Zn →K2 [Zn (CN)4] + 2 Au↓
The precipitated gold is recovered by filtration. It is further purified by electro-refining.5) Electrolytic refining:
This technique is used whenever very pure gold is needed. The impure gold made the anode whereas a thin sheet of pure gold performs as the cathode. The electrolyte contains a solution of auric chloride (AuCl3) acidified with 10-12 percent HCl. On passing current, the pure gold gets acquired on the cathode.
Latest technology based Chemistry Online Tutoring Assistance
Tutors, at the www.tutorsglobe.com, take pledge to provide full satisfaction and assurance in D Block Elements homework help via online tutoring. Students are getting 100% satisfaction by online tutors across the globe. Here you can get homework help for D Block Elements, project ideas and tutorials. We provide email based D Block Elements homework help. You can join us to ask queries 24x7 with live, experienced and qualified online tutors specialized in D Block Elements. Through Online Tutoring, you would be able to complete your homework or assignments at your home. Tutors at the TutorsGlobe are committed to provide the best quality online tutoring assistance for Inorganic-Chemistry Homework Help and assignment help services. They use their experience, as they have solved thousands of the Chemistry assignments, which may help you to solve your complex issues of D Block Elements. TutorsGlobe assure for the best quality compliance to your homework. Compromise with quality is not in our dictionary. If we feel that we are not able to provide the homework help as per the deadline or given instruction by the student, we refund the money of the student without any delay.
primary users for financial accounting is external and internal for management accounting. primary organizational focus is whole for finalcial accounting and segmented for management accounting.
on/off 2 display, left and right selection key, navi key: 4-way scroll key and middle selection, cell key, keypad, end key, microphone, charger connector, audio connector, speaker, camera
Overhead costs are also known as indirect or supplementary costs. These are costs that cannot be completely debited directly to a specific job.
www.tutorsglobe.com - offers cost allocation homework help, cost allocation assignment help, answering questions to cost allocation accounting problems, online tutoring by live online tutors.
tutorsglobe.com general characteristics assignment help-homework help by online viruses tutors
Synthetic Polymerization tutorial all along with the key concepts of procedure of polymerization, Synthetic polymer materials, Addition polymers
basis of cell structure and development tutorial all along with the key concepts of fundamental cell structures, omnis cellula e cellula, types of cells and organelles
Nutrition in Plants tutorial all along with the key concepts of Autotrophic form of nutrition, Heterotrophic form of nutrition, conditions essential for Photosynthesis, Importance of Photosynthesis and Nitrogen Cycle
Natural gas origin tutorial all along with the key concepts of Formation of Natural Gas, Natural Gas under the Earth, Deep Natural Gas, Tight Natural Gas, Shale Gas, Coal Bed Methane, Geopressurised Zones, Methane Hydrates, Offshore Gas Fields, Stranded Gas
signal generator is employed to transmit the small ranges of waves. it is also termed as am transmitter.
keynes theory of income and employment & factors influencing the level of investment, www.tutorsglobe.com offers keynes theory assignment help - keynes theory homework help by economics tutor's help.
Motion in Non-Inertial Reference Frame tutorial all along with the key concepts of Time Derivatives in Fixed and Rotating Frames, Accelerations in Rotating Frames, Lagrangian Formulation Of Non-Inertia Motion, Motion relative to earth, Free-Fall Problem
Energy Resources and Environmental Pollution tutorial all along with the key concepts of Air Pollution, Thermal Pollution, Fossil-Fuel Steam Plants, Nuclear Energy, Geothermal Energy, Hydroelectric Power Plant, Tidal Power Plants, Wind Power Plants, Solar Energy
Appoint qualified tutors from Managerial Accounting Assignment Help service at viable prices to secure notable grades.
tutorsglobe.com thrombosis assignment help-homework help by online blood cells tutors
1937702
Questions Asked
3689
Tutors
1494740
Questions Answered
Start Excelling in your courses, Ask an Expert and get answers for your homework and assignments!!