Blogs
Shaker Table & Fine Particles Classification
Table of ContentsWater-FilmsPreliminary ClassificationQuartz and Galena-CurvesSlope Angles & Water Quantities of Best TreatmentPresent and Proposed Practice ComparedShaker Table Speed The adaptation of European methods of concentrating ores to suit the conditions of this country has followed the lines that simplify machinery, diminish labor and increase capacity. Noteworthy instances are the substitution of hydraulic classifiers for the last one or two trommels
Stamp Mill Performance Diagrams
The object of the present paper is to call attention briefly to a novel method of analyzing the action of the ordinary gravity stamp, which has not only thrown much light upon the exact motion of the stamp-head, but promises also to be of value in determining the efficiency of a new mill before setting it to its work of
Volatilization of Silver Ore: Chloridizing Roasting
The latest revised edition of Mr. C. A. Stetefeldt’s book on the Lixiviation of Silver-Ores, which appeared very recently, contains no mention of the volatilization of silver in chloritization-roasting—an omission which is the more remarkable in view of the fact that in former editions of the work this important subject was noticed. Moreover, Mr. Stetefeldt has discussed it to some
Steam Stamp Milling with Amalgamation
Table of ContentsOreMillWoodCapacityWater The use of steam-stamps in the crushing of ore for the purpose of amalgamation has been very limited, and little has been written on the subject. As the writer has been operating a mill of this kind during the past year, it is possible that he may be able to present a few points in regard to
Silver Assaying & Cupellation
A great deal has been written of late regarding the loss of silver in assaying; very discordant results have been published by different writers, and much uncertainty exists concerning even approximate losses in a careful determination of silver, as represented by a fire-assay. In the present paper it has been the aim of the writer to determine as accurately as possible
Settling Tank Spitzkasten Classifier
Table of ContentsForm of the CurrentThe Slope of the Feed-Sole In “ Sorting Before Sizing ” (a paper first announced at the Pittsburgh meeting, but delayed in preparation and now presented at the present meeting) it is shown that if slime-tables are to do their best work on slimes below 0.5 mm. or 0.02 inch in diameter, they must be carefully sorted
Cementation of Gold by Zinc: Dilute & Foul Cyanide Solutions
Some months since, the attention of the author was directed to certain statements to the effect that the gold-contents of foul or extremely dilute cyanide-solutions could not be effectively precipitated in practice by the usual zinc cementation of gold called the “zinc-method”. Such statements caused all the greater surprise, because it is well known that this difficulty is not encountered
Smelter Slags and Mattes Transport
It is obvious that the choice of the method to be employed in the handling of blast-furnace slags and mattes depends upon local facilities and conditions which may indicate as advisable some particular plan. As a result of the variety of such conditions hardly any two smelters use identically the same method, though they be located only a few hundred
Electrolytic Assay
The analysis of refined copper is a subject of great importance, and has not received the attention it deserves. Copper metallurgists, therefore, will welcome the paper of Mr. Heath with satisfaction. The state of the art of the chemical analysis of copper has been such that consumers, if they could not afford to run any risk, have been obliged to
Assay Determination of Arsenic & Antimony
Table of ContentsDetermination of Arsenic as TrisulphideTreatment of Filtrate Containing AntimonyTreatment of Insoluble Residue from the ElectrolyteLaboratory Experiment No. 8Laboratory Experiment No. 9Laboratory Experiment No. 10Laboratory Experiment No. 11Determination of Arsenic & Antimony Separately in Wire Bar & Cathode CopperDetermination of Arsenic as Pyroarseniate Determination of Arsenic and Antimony Together: Instead of separating arsenic from antimony in the hydrochloric-tartaric acid solution which was finally obtained, dilute
Leaching Sulfides by Sulphuric Acid: Copper
Table of ContentsAcid Leaching PlantBoiling PotsDissolving TankFiltersPrecipitating TanksSilver FiltersEvaporatorsCrystallizersResidue FiltersAcid StorageSilver DryerHydraulic PressMelting FurnacePulverizerPumpsInstallationProcessPractical OperationsSuppliesLaborReturnsBoiling Sulphides in Strong Sulphuric Acid The improvement in leaching introduced by the Russell process has stimulated the development of processes for refining lixiviation-sulphides. In the early days several processes for dealing with the sulphides were proposed, and some of them were tried more or less
Cyanide Chemistry & Gold Extraction
Table of ContentsSolution of Gold in Cyanide SolutionsSolution of Metallic Gold in Potassium, CyanideWhat Effect Oxidizing Agents has on LeachingSolubility of Gold Sulphide in Potassium CyanideSolubility of Gold Telluride in Potassium CyanideSolubility of Antimonide of Gold in Potassium CyanidePrecipitation of Gold from Cyanide SolutionsRegeneration of Potassium Cyanide from Dilute Solution by AcidificationPrecipitation of Gold from Auro Cyanhydric AddPrecipitation of Gold from Potassium-Aurocyanide
Plunger Jig & Accelerated Jig
In the discussion of my paper on “ Close Sizing Before Jigging,” Mr. Louis remarks: “ What we really need to know as the basis of any consistent theory (of jigging) is what occurs during each hundredth of a second.” It is clear that for the further study of the laws involved, a jig-tester is needed which will give curves
Gravimetric Analysis Precipitation Reactions Examples
Table of ContentsDirect EstimationsDirect Estimation by LossIndirect EstimationEstimations by DifferencePure Arithmetical CalculationCalculation by FactorsCalculation by LogarithmsCheck Results of the Analysis of a Mixture Analysis of Chemical Compounds Checks The conditions essential to accurate gravimetric analysis have been given. As a rule such estimations come under one of four classes: Direct Estimations These are the most usual and accurate methods of gravimetric
Quantitative Chemistry Gravimetric Analysis: PRECIPITATE
Table of ContentsDRYING & IGNITING THE PRECIPITATEThe Apparatus requiredMethods of IncinerationWEIGHING THE PRECIPITATETable of Atomic Weights WASHING THE PRECIPITATE: A precipitate may be washed directly on the filter, or it may be washed partly by decantation and partly on the filter. If by decantation, the precipitate is allowed to settle, and the supernatant liquid is poured on the filter. Wash water is
Gold in Granite & Plutonic Rocks
A recent paper by Prof. George P. Merrill, Curator of the Department of Geology of the U. S. National Museum, Washington, upon ” An Occurrence of Free Gold in Granite,” describes an interesting instance of the dissemination of this noble metal in the substance of granite of normal composition believed to be from Sonora, Mexico. He found the gold in
Muffle Furnace
The accuracy of the silver-assay depends in great measure upon a careful regulation of the heat of the muffle furnace during the process of cupellation. At the beginning of the operation, a relatively high temperature is required to ” open ” the lead buttons, that is, to clear off the black film of oxide that covers the surface of the
Conveyor Belts
About six years ago the writer had occasion to visit a large magnetic iron-ore concentrating-plant, and then saw for the first time rubber belts employed for conveying-purposes. These Conveyor Belts were from 20 inches to 30 inches in width, and some of them were as long as 500 feet between centers. When I spoke of the enormous amount of material
Gravimetric Analysis: Substance into Solution
Table of ContentsMethods of Solution & Apparatus usedSaturated solutions Material of Vessels for Solution The student must consider the effect of the solvent used on the vessel. In most cases the solvent used is an acid or mixture of acids, and for such solvents glass and porcelain are generally used. Platinum may be used, provided no chlorine or other attacking agent
Gravimetric Analysis: Precipitation
After solution, certain minor operations may or may not be necessary, but as a rule the next essential operation is that of precipitation. In his qualitative work the student has already come across many cases of precipitation, and he will find that many of the methods there used are again applied for quantitative purposes. Silver, for instance, is precipitated as
Gravimetric Analysis: Precipitate Filtration
Table of ContentsFiltering MediumMethods of Gravimetric Precipitate FiltrationFiltration unaided by a vacuumFiltration accelerated by a vacuumAccelerated Filtration through PaperAccelerated Filtration through Asbestos—Gooch Crucible & Platinum Cone When precipitation is complete the precipitate must be separated from the solution. The means of bringing about this separation will be described under this head. Under the next head (Washing) the completeness of this separation
Assaying of Silver
Table of ContentsScorification-AssaysCrucible AssaysSilver Sulphide Assaying Methods There has been considerable discussion of late as to the best method of determining the silver-contents of sulphides of silver resulting from the leaching of silver-ores, and also as to the relative merits of the crucible and the scorification method for the determination of the silver-contents of ores. Owing to the great depression
Working Principles of Jig: Pulsion & Suction
Table of ContentsJig AccelerationJig Suction ExplainedFull Pulsion with no SuctionWorking Principles of jigging are pulsion & suction Jig Acceleration Rittinger, having found that jigs save galena of smaller sizes than his formula, worked out in his appendix of the theory of acceleration to account for that fact, showing that a particle of galena which is equal-settling with a particle of quartz reaches
Pre-Sizing Jig Feed Classification
Table of ContentsEqual-Settling ParticlesInterstitial Currents The extent to which sizing by sieves should be carried, as a preliminary to the separation, by jigging, of minerals of different specific gravities, has been a matter of controversy for many years. The subject has been investigated by several authorities, yet the ground does not seem to have been completely covered, nor are the