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Assay Method of Gold or Silver in Leach Solution
Table of ContentsGold & Silver Assay Method No. 1Gold & Silver Assay Method No. 2Assay Method No. 3 of Gold & Silver (Virgoe)Method to Assay for Au & Ag No. 4 (Chiddey-Magenau)Estimation of Gold in Cyanide Solution by ColorimetryColorimetric Estimation of Silver in Cyanide Solutions Gold & Silver Assay Method No. 1 Evaporate a known quantity in a square boat made of lead foil, scorify, and cupel. This is not
Principles of Gold Cyanidation Explained
What is commonly known as the Cyanide Process has for its object the commercially profitable recovery of gold and silver from their ores, and this is accomplished by the solvent action of an alkaline cyanide solution on the precious metals. The first step in the Cyanidation process is to mill or grind the ore to a fine state of subdivision
Chemistry of Cyanidation of Gold & Silver
Table of ContentsHow does Cyanide Leach Silver SulphideWhat is the Function of Oxygen in cyanidationCyanide Reducing AgentsEffect of Temperature on cyanide leachingDissolving Effect of Zinc-potassium CyanideFouling of Cyanide SolutionsStrength of Solution in CyanideSources of Cyanide LossThe Use of Lead SaltsPremature PrecipitationCyanide RegenerationRelative Dissolving Efficiency of Sodium and Potassium Cyanide The usual reaction given for the dissolution of gold and metallic silver
Compare NaCN Sodium Cyanide VS KCN Potassium Cyanide
There is probably no potassium cyanide now made for commercial purposes. With the development of the cyanide process the custom grew up, for economic reasons, of manufacturing what was called a “double salt” composed of potassium and sodium cyanides in varying proportions. This material was compounded so as to have a cyanogen content of 98% to 99% in terms of
List Sources of Cyanide Loss
Table of ContentsThe Precious MetalsLoss in Zinc PrecipitationMechanical LossesDecomposition LossLosses Due to Base MetalsLoss in the Form of FerrocyanideLoss in the Form of Sulphocyanate Below is a list of things/factor which can cause cyanide loses in the leach process: The Precious Metals The amount of cyanide that combines with the gold in an average ore is negligible, but with silver
Gold Circuit Carbon Sampling for Inventory and Movement
Metallurgical performance of gold and silver mineral processing flowsheets is typically evaluated using assay balance and production balance techniques. With assay balance the mill feed, tailings, and some intermediate streams are sampled and assayed. Gold circuit performance can then be evaluated using mass balance techniques. Unsteady plant conditions and difficulties in sampling and measuring moving streams are some problems with this method. Production balance measures two rather tangible quantities, tons
Cyanide Reflux Distillation Apparatus
Distillation Procedure Samples without sulfide. Place 500 mL of the combined sample or an aliquot diluted to 500 mL in the 1 liter boiling flask. Pipet 50 mL of 1.25 N sodium hydroxide into the absorbing tube. If the apparatus in Figure 1 is used, add distilled water until the spiral is covered. Connect the boiling flask, condenser, absorber and
Assay gold and silver in cyanide solutions
Table of ContentsEvaporation {Litharge) MethodEvaporation (Lead Boat) MethodCopper Sulphate MethodPrecipitating SolutionChiddy MethodColor Test for Barren SolutionsColor Test for Silver In the assay of gold and silver in cyanide solutions the degree of accuracy and the speed desired are the governing factors in the choice of methods used and the quantity of solution taken for the determination. Evaporation {Litharge) Method To an
Assaying for Zinc in Cyanide Solution
Table of ContentsProcedureSTANDARD POTASSIUM FERROCYANIDE, K4Fe(CN)6, SOLUTIONURANIUM (URANYL) ACETATE INDICATOR Zinc usually occurs in cyanide solutions as the double cyanide, but under certain conditions, e.g., in dilute solutions, a portion of the zinc may be present as zinc cyanide. It is possible that some may also exist as an alkaline zincate. Procedure To 500 cc of solution add 10 cc
Analytical Method for Determination of Copper in Cyanide Solution
Table of ContentsShort Iodide MethodStandard Sodium Thiosulphate SolutionSTARCH SOLUTIONColorimetric Method Short Iodide Method To 200 to 500 cc of solution add 10 cc HCl, 5 cc HNO3. Evaporate to about 50 cc, then cool, and add 8 cc H2SO4. Evaporate almost to dryness. Cool, add 5 cc water and 5 cc H2SO4, and again evaporate almost to dryness. Cool, add
Test for Traces of Cyanide
Here is a Qualitative Test Method to look for Cyanide Traces. To 500 to 1000 cc of the solution to be tested add 1 to 2 cc ammonium sulphide, (NH4)2S, and evaporate just to dryness. The final stages of evaporation should be done slowly. Cool, add 10 cc water, stir well, let settle, and filter. To the filtrate add 2 drops of saturated
Ferrocyanide Assay Determination
Table of ContentsVolumetric MethodProcedureColorimetric MethodSTANDARD IRON SOLUTIONDetermination of Reducing Power The most reliable method of determining ferrocyanide in a cyanide solution is to determine the total iron and calculate to ferrocyanide. Volumetric Method Procedure To 200 to 500 cc solution, depending upon the quality of ferrocyanide thought to be present, add 10 cc HCl and 5 cc HNO3, and evaporate
Measure the Oxygen Content of Cyanide Solutions
Table of ContentsWhite MethodTESTING THE CYANIDE SOLUTIONWeinig-Bowen MethodDetermination of Reducing Power Two methods for determining the oxygen content of cyanide solutions are offered as being simple and accurate. White’s method is a colorimetric one, depending on the degree of coloration imparted to a solution of pyrogallic acid in the presence of caustic soda. Weinig and Bowen’s method, a modification of that
Free Lime CaO Determination Protective Alkalinity
It is important to know the free, or available, CaO in burnt or hydrated limes, especially for the laboratory determination of lime consumption in cyanide tests. The so called sugar method is a convenient one and is widely used. It is based on the solubility of the CaO present in sugar solution. The carbonates and other oxides are unaffected. Procedure
Thiocyanate Assay Determination
Table of ContentsDetermination of Thiocyanate by ColorimetricDetermination of Thiocyanate by Permanganate MethodDetermination of Reducing Power Determination of Thiocyanate by Colorimetric To a 100- cc Nessler tube add 50 cc water and 5 cc (more if necessary) of the cyanide solution to be tested, then add 2 cc HCl and 10 cc of 5 per cent solution of ferric chloride, FeCl3 Mix, and dilute
Determination of Total Cyanide
Table of ContentsDetermination of Total Cyanide by DistillationANALYSIS OF CYANIDE SOLUTIONS Total cyanide is a term used to indicate, in terms of NaCN (or KCN), all the cyanogen existing in the form of simple cyanides, hydrocyanic acid, and the double cyanide of zinc. Procedure. Measure 25 cc of clear cyanide solution, add 10 cc of caustic soda-potassium iodide solution, and
Free Cyanide Determination
You will perform this titration to obtain your Free Cyanide Determination. Take a 10ml aliquot of pregnant liquor. Make aliquot to 60ml with distilled water. Add 3 ml KI (10% solution) Add 5 ml of 1.5% NH4OH Titrate with 0.10 N Ag NO3 then; titre/100 = %CN Note: The endpoint is indicated by the first sign of a change from
Mineralogy & Density of Minerals
With the recognition of a need for a concise table of conversion factors, the following data applicable to metallurgical needs are taken from a compilation by Robert B. Fisher formerly of the Dorr Company for its staff: SLIME-DENSITY TABLE In Metallurgical and Chemical Engineering (now Chemical Engineering) for June, 1912, H. B. Lowden presented the following table and explanatory text
Mineral Processing Operating Cost Estimate of Ore Treatment
Table of ContentsDIRECT CYANIDATION COSTFLOTATION AND CYANIDATION COSTFLOTATION, ROASTING, AND CYANIDATION COSTLOW-COST OPERATION IN THE UNITED STATESCOSTS ON THE RANDCyanidationPOWER CONSUMPTION ON THE RAND Only where a group of mines operates in a single district are costs comparable and then only with reservations. In general, cost systems are fairly uniform, yet in studying costs of a number of plants it is
Manganese Silver Ore Treatment Method
Table of ContentsNATIVE SILVERSILVER SULPHIDESCrushing Silver OreGrinding Silver OreThickeningSilver Ore AgitatingFiltrationClarification and PrecipitationMelting and Refining Silver OreExtractionTreatment of Silver Ores at TonopahPROCESSING MANGANESE SILVER ORESCaron ProcessTypes of Silver Ores with Possible Extraction MethodsPossible Extraction MethodsApplicable Chemistry of Silver ExtractionProduct Recovery Methods The present is to discuss some of the current silver-treatment plants and also reviews briefly some of the older practices in important
Handling Waste Cyanide Solution
Tailings pulp carrying traces of cyanide and the discard of barren solutions in some cases constitutes a hazard to both humans and animals, and methods have been devised for destroying the contained cyanide. A recent paper “The Treatment of Cyanide Wastes”by Chlorination by J. G. Dobson published in the Sewage Works J., November, 1947, discusses the subject as follows; Free
Gold Chlorination Processes & Methods
Table of ContentsDry ChlorinationChlorination Process for GoldWet ChlorinationChlorination and AmalgamationPatio ProcessPan-Amalgamation ProcessChloridizing Roasting and LeachingPatern processAugustine processTainton processHolt-Dern processChlorine Volatilization of Gold In Liddell’s Handbook of Nonferrous Metallurgy, Vol. 2, 1945, there is to be found a very complete account of the uses of chlorine as applied to the recovery of gold and silver, in Chlorination Processes & Methods. Introducing the chapter
Bromocyanide Process
Bromo salts are a mixture of 57 per cent sodium bromide, NaBr, and 43 per cent sodium bromate, NaBrO3, in the form of light-gray, light- yellow, or reddish-brown crystals or powder. The use of bromo salts for treating a telluride concentrate in the Wright- Hargreaves plant at Kirkland Lake is described by J. T. Willey in E. and M.J., July
Cyanide Regeneration Processes and Methods
Table of ContentsCyanide Recovery OR Cyanide RegenerationPrinciples of Cyanide RegenerationCyanide Regeneration at Pachuca, MexicoCyanide Regeneration at HudBay MineralsGold-copper Residue TreatmentCyanide Regeneration ProcessION EXCHANGE USING SYNTHETIC RESINSIon ExchangeAmmonia-cyanide ProcessPretreatment to Remove CopperRoasting Followed by LeachingHandling Waste Cyanide SolutionGold Chlorination Processes & MethodsBromocyanide ProcessCarbon CyanidationCyanide Regeneration MethodsCrosse’s Method of cyanide regeneration Cyanide regeneration offers a practical means of overcoming the otherwise heavy cyanide consumption frequently encountered in the