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Measurement Principle 'Free' cyanide The Cynoprobe uses an amperometric technique to accurately and reliably measure the concentration of cyanide available to leach gold in a pulp medium. Amperometry Potentiometric Titration Cynoprobe measures the cyanide available for the leaching of gold. It not only measures free cyanide but also the cyanide


Mining – cyanide leaching process Measurement made easy — Introduction Leaching involves the dissolution of a mineral from a solid (ore). The process contacts the ore with a solution containing reagents that dissolve the required mineral (and often some non-required materials). Various methods – carbon adsorption,


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ANALYSIS OF CYANIDE

Most cyanide measurements require distillation prior to the measurement. The purpose of distillation is simple: Sample clean-up. (in the case of cyanide, there can also be digestion). The distillation process transfers the analyte from the sample into a clean, reproducible solution, for more accurate measurement. In some cases, it can also provide


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CYANIDE MANAGEMENT

CONTENTS ACKNOWLEDGEMENTS vi FOREWORD ix 1.0 INTRODUCTION 1 2.0 CYANIDE IN MINING 3 2.1 Cyanide in context 3 2.2 Gold extraction 5 2.3 Alternatives to cyanide 7 2.4 Cyanide treatment, recovery and reuse 7 2.5 Control of process losses 8 3.0 CYANIDE AND THE ENVIRONMENT 9 3.1 Cyanide ecotoxicology 9 CASE STUDY: Sunrise Dam gold mine, …


The ABB solution: TB556 for pH measurement. Cyanide leaching is a difficult process as the process liquid is in abrasive slurry which can result in damage to the glass electrode. The use of lime reagents can cause hard …


Measuring cyanide in the leach liquors associated with high copper and/or sulfide ores is a non-trivial exercise. It is well known that copper complexes with cyanide and reduces the amount of ...


WAD and Free Cyanide: Unlike for the measurement of total cyanide, nitrate and nitrite do not interfere with the measurement of WAD or free cyanide, therefore the addition of sulfamic acid is not required for these tests. c. Residual Chlorine / Oxidizing Agents: Oxidizing agents such as chlorine can decompose most cyanide complexes.


Cyanide Analysers. CyantificTM process analysers give you the measurements you need to manage your cyanide processes. Whether you are controlling dosing, leaching, detox or discharge, there is no longer a need to rely on infrequent and …


Cyanide leaching is the dominating process for gold recovery from primary resources, due to its simplicity and high cost efficiency. ... The measurement consisted of taking out the sample from ...


The Cynoprobe provides high frequency measurement of both free and weak acid dissociable (WAD) cyanide in up to three streams. Cyanide reagent costs form a significant part of a gold plant's operating budget – the Cynoprobe's measurement can be incorporated into a control scheme in an effort to reduce excess cyanide addition.


The measurement consisted of taking out the sample from leaching solution, drying with compressed air, measurement of weight and geometry and putting it back. This procedure took 1 min on average, which is not considered in the total leaching time (i.e. there is a negligible deviation between of displayed and real leaching time of ~1.7%).


to cyanide leaching. These processes also have pH measurements but will be reviewed in a separate paper. Low grade ore is often processed using a heap leach process. Heap leaching involves crushing the ore to <3/4" (<19mm) diameter chunks and piling on a puncture-proof liner. The liquid cyanide solution is poured over the heap


In cyanide leaching plants, free cyanide level in leach solutions is commonly controlled by silver nitrate titration. The presence of zinc in solutions leads to an overestimation of free cyanide ...


Measuring pH in Cyanide Leaching Background Process pH Measurement Precious metals such as gold and silver are processed using cyanide compounds. Cyanide dissolves the precious metal by forming a chemical complex with it, thus separating the precious metal from the other constituents of the ore, which do not dissolve. The


An on-line cyanide analyzer for measuring available cyanide in leaching and detox solutions by U.S. EPA Method OIA-1677 and ASTM D 6888 is now available. The CNSolution 9310 analyzer can be used as a benchtop analyzer for grab samples or deployed for on-line measurements and process control. 35


The ongoing depletion of gold and silver-containing ore deposits demands a shift towards the processing of more complex sources. Leaching of gold or silver from these sources, which are named refractory and are typically low-grade, can be complicated due to one or more of the following effects: (1) kinetic or thermodynamic impediments on cyanide diffusion or on the …


To avoid hydrolysis of cyanide [, leaching must be carried out under alkaline conditions: (26.2) CN – + H 2 O → HCN + OH – However, in saline water, such as in many cyanidation plants in Western Australia, gold leaching is performed at a pH below 10 to reduce the high cost of lime under these buffering conditions.


An experiment on cyanide leaching of finely disseminated gold ore (104 µm grain size, pH ≥ 10.5) indicated that higher gold dissolution (97.5%) occurred after about 40 hours of leaching time 39.


Gold mining wastes treated by heap leaching cyanidization typically contain several metallo-cyanide species. Accurate measurement of total cyanide by the most common methods in such a case may be hampered by the inadequate recoveries that occur for certain cyanide compounds (e.g., gold cyanide).Accurate measurement may be further hampered by the …


The Cynoprobe, a product from Mintek, offers the functionality to measure both 'free' and weak acid dissociable (WAD) cyanide concentration of up to three streams or sampling points. This results in a very cost-effective cyanide measurement solution. Cyanide reagent costs form a significant part of a gold plant's operating budget.


Accurate measurement of cyanide in leaching solutions. CNSolution TM 9310 In operation, a filtered slurry sample is drawn into the CNSolution 9310 to fill a fixed volume loop. A base reagent is continuously pumped through one side of a gas diffusion module equipped with


The silver nitrate titration method is a rapid and acceptably accurate means of analyzing for cyanide in leach solutions that contain primarily free cyanide. However, in leach solutions containing elevated levels of copper, the titrimetric method overestimates the concentration of free cyanide and underestimates the concentration of weak and dissociable …


We claim: 1. A process for leaching gold and silver from noble metal containing material; namely, ores or ore concentrates comprising leaching said material with an aqueous cyanide leaching solution having a pH of from 8 to 13 and adding a diluted aqueous H 2 O 2 solution containing from 0.5 to 5% by weight H 2 O 2 to said leaching solution during said leaching, said aqueous …


Cyanide Leaching Chemistry. In a relatively simple system of this type the gold dissolves readily. The only requirements are that the gold be free and …


cious metals where cyanide is commonly used, both pH and ORP measurements are essential for efficiency and safety of per-sonnel. For example, pH values below 11 may allow the formation of hydrogen cyanide (HCN) which is a highly toxic, yet colorless gas. Since the formation of HCN removes active cyanide from the leaching process, effective pH ...