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Metallurgical Testing Program & Management
Table of ContentsFlotation Process Flowsheet Metallurgical testing and corresponding flowsheet development programs involve acquisition of certain basic information, a laboratory testing phase, the preparation of reports and, finally, flowsheet development. Management of the basic information includes information relevant to location, the nature of the ore body, sampling, marketing and specifications, environmental guidelines, and a review of literature and current practice. The
Roasting in Metallurgy
Table of ContentsChemistry of Oxidising RoastingIron Pyrites, FeS2Roasting Copper PyritesGalena, PbS – RoastingRoasting Arsenical Pyrites, FeAsSAntimonial Sulphide RoastingBlende, ZnS RoastingCarbonate of Lime, CaCO3Tellurides RoastingMetallic Gold, Silver RoastingRoasting to Eliminate Arsenic and AntimonyThe Use of Salt in RoastingLosses of Gold in RoastingCooling Roasted Ore In metallurgy, the operation of roasting, as a preliminary to chlorination, has for its object the expulsion of the sulphur, arsenic,
Mechanical Types of Furnaces used in Metal Industry
Table of ContentsFurnaces with Mechanical Stirrers—O’Hara FurnaceSpence FurnaceMacDougall, Herreshoff, and Evans-Klepetko FurnacesPearce Turret FurnaceThe Brown Horse-shoe FurnaceRevolving Cylindrical FurnacesThe Hofmann FurnaceThe White and White-Howell Roasting FurnacesThe Argall Roasting Furnace The furnaces which have been designed with the object of saving the labour necessary to work the reverberatory furnaces may be divided into four classes: Stationary hearth furnaces, supplied with iron
Reverberatory Furnace
The construction of the ordinary reverberatory furnace is too well known to need detailed description here. It consists of a vaulted chamber, containing the ore; through this chamber, the flames and products of combustion from a reverberatory furnace and a current of air are made to pass in a horizontal direction above the ore, which is thus heated. The ore is
Tube Mills
Tube Mills consist of revolving cylinders, the interior of which is perfectly plain. They contain a number of hard balls. They differ from ball mills essentially in having the inlet for ore at one end and the outlet at the other, and in the absence of provision in the machine itself for the return of uncrushed material (oversize). It is therefore
Roll Crushing VS Stamp Milling Compared
Comparison between Rolls and Stamps: As the subsequent treatment of an ore determines its method of crushing, no accurate general comparison of stamps and rolls can be made. A comparison is only possible in the special cases where both methods of crushing are applicable. Wet crushing by rolls need not be considered, as it is not practised; even where the advocates
Round Buddle
The Round Buddle was invented in Cornwall, where it is still used in dressing the tin ores to the exclusion of almost every other concentrator. There are two varieties. The convex round buddle, in which the ore and water are added at the centre of the machine, and flow down over the surface to the periphery. The concave buddle, in
Gold Gravity Concentration
The object of gravity concentration is the separation of the heavy valuable mineral from the light worthless gangue. Complications are often introduced by the fact that various base minerals must be separated from one another, an ore being subdivided into several products. Most gold ores, however, only require separation into two parts—the “concentrates,” in which the precious metal is contained,
Concentrating Gold with Oil
It has been found that in the case of certain ores, residuum oil separates sulphides and metallic particles from earthy or stony materials without reference to their respective densities. In the Elmore concentrating process, which was introduced at Glasdir, near Dolgelley, in Wales, the ore is crushed in Huntington Mills, and the pulp mixed with oil in a revolving drum. The
Gold Settling Box
Gold Settling Boxes are of the same shape as the spitzkasten or pointed boxes introduced by von Rittinger. They are for the purpose of allowing the sand and mineral in suspension in a flowing current to settle, so that the part of the water not needed in the subsequent treatment of the ore may be run off; if it is desirable,
Frue Vanner
The Frue Vanner is described in detail as being typical of the shaking travelling-belt concentrators. Machines of this class are especially adapted for treating finely-crushed battery sands which do not contain a large percentage of “mineral” (that is, sulphides and other heavy materials). They are frequently set to concentrate unsized pulp coming straight from the amalgamating tables. The Frue vanner (Fig. 47) consists
Grind Size & Liberation for Optimum Flotation Recovery
Here is a trick for knowing if your flotation feed grind size is fine enough to achieve adequate mineral liberation without doing a full mineralogy study. If your key mineral is sufficiently liberated, it should float and be recovered in the first few minutes in an initial %mass that stabilizes quickly = the green curve. If, your valuable minerals are
How to Read a Burette
To help you read a burette, first obtain a 3″x5″ card and with a black felt tip pen make a horizontal mark on your card, one inch thick and practically the length of the card. When the top of the black band is held just below the bottom of the meniscus you will see a reflection of the band in the meniscus against the white of the card behind.
Steam Powered Stamp Mills
Since within certain limits and under certain conditions the capacity of a stamp battery depends on the number of blows given per minute and on the momentum of the fall, various contrivances have been suggested with a view to increase both of these. In pneumatic stamps, such as the Husband and Phoenix stamps, a crank shaft raises the stem, which
Roller Mills
In the Griffin Mill, there is a single roller suspended in a similar way to the rollers in a Huntington mill. The roller is about 18 inches in diameter, and rolls on the inside of a die ring 30 inches in diameter. It takes material up to 1½ inches in diameter, and crushes either wet or dry. It does not
Huntington Mill
The Huntington Roller Mill, here described as a type of the many good roller mills now in use, is best suited for the fine crushing of ores which are not too hard. It consists of an iron pan, at the top of which a ring, B (Fig. 40), is set, and attached to this are three stems, D, each of which
Amalgamation Pans
Table of ContentsAmalgamation Pans Operating PrincipleBoss Continuous SystemTreatment of Concentrates in the Pan An amalgamation pan consists of a circular cast-iron pan, provided on the inside with a renewable false bottom of cast-iron—constituting the lower grinding surface—and a “muller,” of upper grinding surface (d, Fig. 42), attached to a vertical revolving spindle, g, which is set in motion by bevel
Stamp Battery
The stamp battery must be regarded from two different points of view, (a) as a crushing machine, (b) as an amalgamating machine, and it should be remembered that the modifications designed to make it a more efficient crusher often reduce its power as an amalgamator, and vice versa. Stamps were originally designed as crushing machines, and the tendency is just now
Optimize Gold Amalgamation Recovery
Minimizing losses of gold in amalgamation will result in optimum Gold Amalgamation Recovery which may be ranged under the following heads: Loss of free gold contained in amalgam, due to flouring of mercury, scouring of plates. This has been dealt with above under the heads “Treatment of the Plates” and “Loss of Mercury.” Loss of gold which “ floats ” in water
Rusty Gold
The appearance in the tailings of free gold, which is not especially finely divided, but, nevertheless, is not in a condition to be amalgamated, may be regarded as a rare occurrence, but deserves some consideration. Amalgamation is in these cases prevented by the existence of a thin film of some neutral substance over the surface of the gold. The film
How to Separate Gold from Pyrite
So far, no account has been taken of the loss of gold which is contained in pyrites, as it has been assumed that these are saved by concentration if they are valuable, and this subject is dealt with in earlier. Nevertheless, as this gold comes under the head of non-amalgamable gold, its physical state and the causes of its disinclination
How Mercury & Gold Amalgamation Works
Table of ContentsDiscoloration of the Copper PlatesWhat Chemicals to Used for Better AmalgamationAmalgamation Plate Angle & DesignMuntz Metal PlatesShaking Copper Amalgamation PlatesMercury TrapsGalvanic Action in AmalgamationDesignolle Process of AmalgamationHow to The Clean Amalgamation Plates In order to keep the plates in proper condition so that successful amalgamation may be maintained, they must be prepared carefully, and the closest watch kept over
Mercury Retorting
Table of ContentsMinimize Mercury LossesProperties and Purification of MercuryTypes of AmalgamHow to Purify Mercury The solid amalgam, which is retained in the canvas or wash-leather filters, usually contains from 30 to 45 per cent, of gold and silver, according to the state of division of the gold present in the ore, and also to the degree of care exercised in squeezing out
Using Mercury in Gold Ore Crushing
Table of ContentsAmalgamation PlatesHow to Install Amalgamation Plates & How Amalgamatiing Plates Work The earliest machines used for the purpose seem to have been stone mortars, in which the gold quartz was crushed by stone-hammers, or by large rocks raised by levers and let fall, whilst the fine material was subsequently washed out with water. The heavy particles of gold then