Blog of Mineral Processing (Metallurgy) Articles

Mineral Processing and Extractive Metallurgy Methods

A successful search for and development of a new mineral deposit rests not only in its discovery but also in economical processing of the ore. Via the Science of its engineering, Mineral Processing and Extractive Metallurgy allows the evaluation of metal recovery Methods laid-out or expressed as a process flowsheet.

The challenge of discovery and development, the processing and profit from mineral resources have resulted in many different process flowsheets. There has been a constant advance in mineral technology for hundreds of years. The process flow we consider highly successful today may

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By | April 14th, 2016|Categories: Concentrator Manuals/Procedures, Flowsheets & Flowcharts|Comments Off on Mineral Processing and Extractive Metallurgy Methods

Gold Refining Process

To present the essential points of all methods of gold refining commonly practised, as well as those of historic interest,” was the author’s purpose in this volume. The fifteen chapters of which the book consists deal with the Simpler Methods of Early Days;

Amalgamation Process; Refining with Oxidising and Chloridising Agents;Gold Refining Sulphur Refining; Refining with Cementation Processes, and by means of Oxygen and Air; Miller’s Process and that adopted at the Melbourne Mint; Parting with Nitric Acid (two chapters); Recovery of Silver from Nitrate Solutions; Refining by Sulphuric Acid; Parting by Electrolysis; Electrolytic Refining of Gold; Separation of Platinum from Gold; Treatment of Cyanide Precipitates; Refining of Gold Slimes by Nitric and Sulphuric Acid; the Nitre Cake Method of Purifying Slimes.


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By | April 1st, 2016|Categories: Gold Refining|Tags: , , |Comments Off on Gold Refining Process

Mineral Processing Flowsheets

The Mineral Processing Flowsheets shown on the following pages are based on actual data obtained from successful operating plants. Metallurgical data are shown in these flowsheets which incorporate Crushers, Grinding Mills, Flotation Machines, Unit Flotation Cells, and Selective Mineral Jigs as well as other standard milling equipment.

The Flotation Machine, the Selective Mineral Jig and the Unit Flotation Cell have revolutionized flowsheet design and have made it possible for both small and large plants to increase recoveries and economical return. The Unit Flotation Cell and

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By | March 8th, 2016|Categories: Flowsheets & Flowcharts|Tags: , , |Comments Off on Mineral Processing Flowsheets

List Types of Gold Placers

Perhaps the best known schemes for the classification of gold placer deposits are those by Jenkins and Brooks, the former being based on conditions of deposition and the latter on present position of the deposit. The field engineer should acquaint himself with these schemes, particularly that by Jenkins which has been developed in some detail. For the usual field investigation a somewhat simpler clarification will be found suitable. This list present all types of gold placer deposits:

  1. Residual placers.
  2. Eluvial placers.
  3. Stream placers.
  4. Bench placers.
  5. Flood gold deposits.
  6. Desert placers.
  7. Tertiary gravels.
  8. Miscellaneous types.
    a) beach placers.
    b) glacial deposits.
    c) eolian placers.



A residual placer is, in effect, a concentration

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By | October 23rd, 2016|Categories: Geology|Comments Off on List Types of Gold Placers

Gold Placer Geology

The source of gold or other minerals found in a placer may be one or more of the following:

a. Lodes or mineralized zones.
b. Erosion of pre-existing placer deposits.
c. Low-grade auriferous conglomerates or glacial debris.
d. Magmatic segregations and associated basic rocks.
e. Regional rocks containing scattered particles of valuable mineral.

a. Lodes:

Although placers are commonly found in lode mining districts, experience has shown that there is no fixed relationship between the richness of the parent lode and the richness or size of resultant placers. Some of the most noted gold mining districts

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By | October 23rd, 2016|Categories: Geology|Comments Off on Gold Placer Geology

Procedure & Method for Activated Carbon Testing Program

OBJECTIVE: Evaluation of Westates Metasorb 321G (6×12) virgin activated carbon as compared to medium activity carbon from alternate vendors.


The following variables will be evaluated:

  1. Apparent density.
  2. Initial moisture content.
  3. Fine carbon losses following pre-soak.
  4. Particle size distribution of pre/post attrited carbon.
  5. Attritioning rates and losses with/without silica media.
  6. 24 hour adsorption rate and activity.
  7. Optimum economics in conjunction with product superiority.


Westates, the current carbon vendor to the Chimney Creek plant, has been a supplier since the inception of mill start-up. Historically, ending fiscal ’92, an increase by 72% in attritioning rates was in evidence as compared to fiscal ’90 (Tables 1 through 4). Proportionately, attrition losses created a 93% dollar increase from $53,070 in ’90 to $102,400 in ’92

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By | October 23rd, 2016|Categories: Gold Refining, Laboratory Procedures|Comments Off on Procedure & Method for Activated Carbon Testing Program

Meehanite Metal

Meehanite is the copyrighted trade name for a uniform, closely controlled iron cast to rigid physical properties. The Mine and Smelter Supply Company pioneered the use of Meehanite as applied to grinding mill construction.

Because of the uniformity of properties and assurance of manufacture according to engineering specifications, Meehanite metal has been selected for use in the construction of ball Mill heads, spur gears, bearings and other castings. Service performance during the past years has thoroughly justified and demonstrated the soundness of judgment in selecting this material.


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By | October 22nd, 2016|Categories: Various|Comments Off on Meehanite Metal

Ball Mill Gear

ball-mill-spur-gearingTwo general classifications of gearing are used for ball Mill drives. These are the spur gear and the helical gear. Helical gearing may be either of the single helical or double helical (Herringbone) design.


These are generally furnished on the smaller diameter mills using V-belt drives or reducer drives. Spur gears and pinions are cut with teeth of the full depth involute tooth form thus assuring maximum tooth strength and long wearing life. The main gear is cut from a special Meehanite metal casting and is constructed split and reversible. The pinion is cut from a steel forging

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By | October 22nd, 2016|Categories: Ball Mills, Grinding|Comments Off on Ball Mill Gear

Ball Mill Drives

Several types of ball mill drives can be furnished, made up of various combinations of gearing, motors and transmission equipment. The correct combination to be selected takes into consideration power requirements, gear ratings, floor space, interference from other plant equipment and motor characteristics. The main types are described and illustrated on these pages.

Motors considered are the squirrel cage motor, wound rotor motor, and synchronous motor. One important advantage of the synchronous motor is the possible correcting of power factor within your operation, through its use. When using

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By | October 22nd, 2016|Categories: Ball Mills, Grinding|Comments Off on Ball Mill Drives

Ball Mill Feed Chute

Each application dictates the selection of proper feeding arrangement. This depends upon whether the grinding will be open circuit or closed circuit, and dry grinding or wet grinding. The size of feed and tonnage rates are also important factors.

Speed of scoop lip is important. Listed below for your convenience is a table showing critical speeds for various radius scoops. Tip of scoop lip speed should not exceed 90 to 95% of critical speed. Beyond this scoop efficiency decreases and scoop will have the tendency to throw material rather than pick it up.



The single scoop feeder provides a

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By | October 22nd, 2016|Categories: Ball Mills|Comments Off on Ball Mill Feed Chute

How to Separate Ferrous & Non Ferrous Metals Scraps

Scrap metal, both ferrous and non-ferrous, present in industrial wastes, slags, smelter bi-products, sludges, refinery sweepings, ashes, etc., can be reclaimed in most instances at a profit and thus are made available for reuse in industry. Very substantial stockpiles of these scrap metal wastes are available for processing in the various industrial areas. through its testing facilities during the past several years, has investigated many of these sources of good reclaimable metal

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By | October 22nd, 2016|Categories: Flowsheets & Flowcharts|Comments Off on How to Separate Ferrous & Non Ferrous Metals Scraps

Pebble Mill Grinding

Essentially tube mills and pebble mills may be considered as ball mills, the basic difference being that the ratio of length to diameter is greater. Usually the shell length is between 2 and 5 times the diameter. These mills are primarily used to grind various materials to 100 mesh and finer. The Tube Mill uses iron or steel balls as the grinding media, and liners of various metals and alloys.

Where iron contamination is detrimental such as in the case of grinding Feldspar for porcelain, Corundum, talc, certain clays, chemicals and glass sand, a pebble mill is indicated. In such

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By | October 22nd, 2016|Categories: Ball Mills|Tags: |Comments Off on Pebble Mill Grinding

Cement Grinding

The principle of Grate Discharge grinding is nearly universally adapted in the cement grinding industry. Grate Discharge Ball Mills are the rule rather than the exception. Rod Mills for raw and finish grinding begin to enter the picture. Larger and larger diameter mills become common. Lengths tend to shorten. Cement grinding using Grate Discharge principles developed in the ore milling industry applied to the cement industry. This experience plus the years of manufacturing know how unquestionably qualify Grate Discharge grinding for the Cement Industry.


This phase of grinding may be either

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By | October 22nd, 2016|Categories: Ball Mills, Grinding, Rod Mills|Comments Off on Cement Grinding