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.
theory and lecture notes of varieties of finite state machines all along with the key concepts of varieties of finite state machines, finite state machines, deterministic finite automaton, non-deterministic finite automaton. tutorsglobe offers homework help, assignment help and tutor’s assistance on varieties of finite state machines.
Approach our apt Russian History Assignment Help tutors and attain excellent grades without any efforts at low prices.
Bit operators and Assignment operators-Homework help, Assignment help including the key concepts of Floating Point, Type conversion, goto and labels.
Orbital Hybridisation tutorial all along with the key concepts of Sp3-Hybridisation, Sp2-hybridisation, Sp-Hybridization
liquidity ratios are considered with the capability of the business to meet its short-term financial obligations.
Application of Symmetry tutorial all along with the key concepts of Formation of Symmetry Point Group, Classification of the Symmetry of Molecules, Point group determination chart, Symmetry Elements in a Molecule, Symmetry in Crystal Structures
Nervous coordination in animals tutorial all along with the key concepts of Divisions of Nervous System, Brain, Spinal cord, Functions of spinal cord, Peripheral Nervous System, Structure of Neuron, Reflex Action and Sensory Receptors
www.tutorsglobe.com offers Pair of Straight Lines homework help, Pair of Straight Lines assignment help, online tutoring assistance, geometry mathematics solutions by online qualified tutor's help.
tutorsglobe.com cholesterol biosynthesis assignment help-homework help by online lipid metabolism tutors
Carbohydrate Chemistry tutorial all along with the key concepts of Monosaccharides, Disaccharides, Oligosaccharides, Polysaccharides, Biological significance of carbohydrate, Stereoisomerism of carbohydrates and Reactions of Carbohydrates
It is importance asking why cash is so important. Nevertheless, the cash is just an asset that the business requires to assist it to function. In that sense, it is no dissimilar from inventories or non-current assets.
Chemistry of nucleotides tutorial all along with the key concepts of Definition of nucleotides, Components of nucleotides, Nomenclature of nucleotides, Derivatives of nucleotides and Significance of nucleotides
Theory and lecture notes of spherical Flow of Economic Activity all along with the key concepts of Spherical flow of economic activity, circular flow, Gross Domestic Product, Economists. Tutorsglobe offers homework help, assignment help and tutor’s assistance on spherical Flow of Economic Activity.
Reflection of Light tutorial all along with the key concepts of Concept of Light, Rectilinear Propagation of Light, Shadows, Eclipses, Pinhole Camera and Reflection of Light at Plane Surfaces
www.tutorsglobe.com offers cost benefit analysis homework help, answering questions to cost benefit analysis, cost benefit analysis assignment help, accounting instant tutoring sessions for cost benefit analysis by online tutors.
1963577
Questions Asked
3689
Tutors
1445602
Questions Answered
Start Excelling in your courses, Ask an Expert and get answers for your homework and assignments!!