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Waagner-Biro ASL Liner System

A unique type of grinding mill liner has been developed by Waagner-Biro A.G. of Austria. This liner system, termed an angular spiral lining (ASL), was successfully tested by Magma Copper Company’s San Manuel concentrator in both their 10 Ft x 10 Ft (3.05m x 3.05m) and 12 Ft, 6 In x 14 Ft (3.31m x 4.27m) grate discharge wet grinding ball mills. Magma Copper’s savings in power and grinding balls justified conversion of more than half of their twenty-six ball mills to the ASL system.

Day shift samples were taken of each ball mill new feed, ball mill discharge, cyclone underflow, and cyclone overflow. Percent solids and screen analysis were determined on each sample. Computer tonnage and power consumption, for the same time period as the sampling, were also obtained. This sample period data was later accumulated for comparison with monthly records on production rate, power and ball consumption.

The original set of ASL liners was tested for nearly four months. Variations were made in the following items during this testing:

  1. Cyclone apex size
  2. Cyclone feed pump speed
  3. Mill discharge sump level
  4. Number of cyclones
  5. Ball mill discharge percent solids
  6. Cyclone feed percent solids
  7. Ball charge level
  8. Ball mill pulp level

Rubber Liners in Autogenous Grinding AG Mills

Wet autogenous grinding is utilized in three iron ore concentrating plants operated by The Cleveland-Cliffs Iron Company (CCI). The Cleveland-Cliffs Iron Company is a natural resources firm with major interests in iron ore mining and processing and oil and gas contract drilling. The company also has interests in oil shale, uranium, forest products, and Great Lakes shipping.

Current Practice – Primary Mills

Sherman Mine initially considered converting from metal to rubber liners in the primary mills because of concerns with: 1) metal war and breakage cost, 2) scheduled downtime for change-out of worn metal, 3) unscheduled downtimes for replacing broken liners, lifters, liner bolts, etc., 4) maintenance due to poor feed end trunnion bearing life, potential mill imbalance and gear problems, and elongated liner bolt holes, and 5) safety considerations in handling heavy metal liners.

The success of the first set of rubber liners led to the installation of the second and third sets in March, 1979 and January, 1980 respectively. Experience with these installations has been comparable to the first set of liners except for decreased wear life of certain rubber lifter bars. The cause of this problem was traced to the manufacturer and a rubber extrusion step of the process

How to Treat Water Containing Cyanide

Metallurgical processes involving the use of cyanide such as gold cyanidation, metal plating and flotation, generate effluents containing cyanide and cyanide in complex combinations with heavy metals in quantities exceeding those regarded as being safe for discharge into streams.

A new, inexpensive method for removal of cyanide, combined cyanide and related species from wastewaters has been developed in Inco laboratories. The method is based on the use of sulfur dioxide (or a sulfite), lime and air as the reagents. The decomposition reactions of cyanide, combined cyanide and related species are catalyzed by copper in solution. Complete removal of cyanide species, most of which are oxidized to harmless cyanate, is obtained by treating copper containing cyanide effluents with sulfur dioxide-air mixtures while maintaining the pH between 6 and 10 with addition of lime.

Effect of Process Variables in the Removal of Cyanide and Related Species

The effects of process variables were usually studied in batch experiments mostly using synthetic liquors. The tests were carried out using a 1 liter capacity stirred reactor, with addition of sulfur dioxide and air premixed at 0.5 to 5 volume percent sulfur dioxide at a rate of 1 liter of air per minute per liter. The pH

Carbon-In-Pulp Process Examples

There are no major innovations in any of these plants. In fact, Australia is really only beginning to get started in CIP research and in process and design development. The plants described here have borrowed from technology, primarily in the United States and South Africa, and although the plants were carefully designed and based on sufficient (if generally minimal) testwork, they are not generally the product of years of research and analysis. The plants are, however, well-designed plants which operate efficiently.

Adsorption

The peripheral screen system uses 8 screen panels per tank, curved to the radius of the adsorption tank. These panels are fixed vertically to the top frame of the tank providing about 90% screen area for overflow.

The airwash system consists of perforated air pipe covered with a Linotex sleeve containing trans verse slits at 30mm (1 in.) intervals. The pipe, supported and fed at each quadrant of the tank, is located 55 mm (2.2 ins.) below and 25 mm (1 in) from the screen. The screens, as currently operated, pass a maximum of 64 tph of solids at about 46% density through 7.3m (24 ft.) of 20 mesh peripheral screen using 7m³/min (240 cfm) of 280 kpa (40

Swirl Flotation in Centrifugal Field by Air Sparged Hydrocyclone

The effects of operating variables on water transport to the overflow, classification of hydrophilic particles and the recovery of copper and molybdenum from a low-grade porphyry ore are presented. Recoveries of copper and molybdenum exceeding 90 percent at a grade of 8 percent Cu and 0.2 percent Mo were realized for minus 100 mesh (149 m) material at retention times of less than 500 milliseconds. The rapid rate of flotation and the effective separation of fine particles for an air sparged hydrocyclone appear to be due to directed interaction of particles in a high force field with numerous freshly formed small bubbles.

Description

The basic features of an air sparged hydrocyclone are: 1) a porous wall through which air is sparged, and 2) a tangential flow of slurry orthogonal to the air flow. A number of different designs incorporating these features have been tested with the preferred design being a vertically oriented, cyclindrical cyclone with tangential feed at the top (Figure 1).

The slurry, fed tangentially through a conventional cyclone header, passes through the separator as a thin layer in swirl flow and travels downwards countercurrent to the froth phase, which is moving upwards in the center of the device. Hydrophilic

Recover Rhenium by Solvent Extraction

Rhenium is industrially recovered all over the world as a by-product of molybdenite processing. There are no separate deposits of rhenium minerals. Molybdenite concentrates, produced as co-products of porphyry copper deposits, contain 0.01 to 0.2% rhenium occuring as a substitutional impurity in the molybdenite lattice.

Process Synthesis

The solvent extraction process is integrated with other processing steps to obtain the ultimate product. The industrial processes for recovery of metal values from low-grade complex sulphide ores usually involve a bulk flotation stage where the sulphide minerals are collectively separated from silicious gangue.

Due to volatile nature of rhenium heptoxide, in contrast with low volatility of other metal oxides, there is high separation factor during oxidative roasting of molybdenite. One of the principal operating variable which influences subsequent rhenium processing is the flow rate of air in the roaster. In conventional multiple hearth roaster large excess of air is needed for rapid convective transfer of reaction heat, and this dilutes rhenium content of the gases and hence of the liquor, for a scrubber operating at constant optimal liquid/gas ratio.

Experimental Work

The experimental work done in the Ore Dressing Section includes the generation of equilibrium separation data under varying process conditions, and the

Use Sodium Silicate as Dispersant in Selective Flocculation

In the upgrading of finely-disseminated iron ores, selective desliming is the critical step which must be controlled in order to achieve efficient flotation. A prerequisite for selective desliming is a properly-dispersed pulp; sodium silicate is commonly used as a dispersant. The mechanism by which sodium silicate acts as a dispersant in the presence of calcium ions was examined by streaming potential measurements, settling tests, abstraction density determinations, selective flocculation tests and scanning electron microscope observations.

Experimental Results

Studies to delineate the manner in which sodium silicate affects selective flocculation of goethite-quartz mixture were carried out employing different experimental approaches. Initially, attempts were made to investigate the adsorption behaviors of Ca++ and silicate, but the unreliability of Ca and Si values obtained by atomic adsorption in the present system ruled out this approach.

Streaming potential measurement results on quartz and goethite as a function of sodium silicate additions at 0, 10 -5M, 10 -4M, and 10-³M concentrations of CaCl2. In the absence of Ca++ the zeta potentials of quartz and goethite decreased gradually with sodium silicate concentration indicating that silicate ions acted, more or less, as indifferent ions towards these minerals.

With calcium ions in solution, there seemed to be some interaction as

How to Separate W from AgNO3 Electrolyte

A prevalent technique for the recovery of silver from wastes generated in silver-tungsten electrical contact fabrication is electrowinning. Such scrap is placed in a permeable plastic basket which constitutes the anode compartment and this basket is suspended in a larger cell in which the cathode is mounted.

Process Design

The solution to this problem lies in the selective removal of the W from the AgNO3 electrolyte either by liquid-liquid or liquid-solid extraction. Although W extraction in the liquid-liquid mode with a quaternary amine or other reagents as extractants appears feasible, particularly in view of the low pH (-1.5) of the system, it was eliminated from consideration because it is essentially a batch type process and it is a more elaborate industrial operation than extraction by ion exchange resins.

A useful material is a gel-type, weakly basic anion exchange resin with a polyamine functionality and in the free base form, the commercial Amberlite IRA-68 manufactured by Rohm and Haas Company. Initial slurry tests with W-contaminated AgNO3 electrolyte showed that the resin extracts W quantitatively but it also coextracts substantial amounts of Ag.

Process Description

The flow diagram of the process for the separation of W from AgNO3 electrolyte

  1. Resin conditioning
  2. Column preparation

Selective Flocculation

Selective flocculation utilizes the differences in the physical-chemical properties of the various mineral components in the mixed suspension. It is based on the preferential adsorption of an organic flocculant on the particular solids to be flocculated, leaving the remainder of the particles in suspension. In order to understand the mechanics of this process, selective flocculation may be divided into four major sub processes; these being: ore slurry dispersion, in which all the particles are stably and uniformly distributed in the suspension with the individual particles being essentially separate; flocculant selective adsorption and floc formation; floc conditioning, which aims at obtaining flocs with desire properties for their subsequent separation and with minimum entrapment of dispersed particles; and floc separation from the suspension.

Design of Selective Flocculation Processes

In designing a selective flocculation process to separate certain desired particles from mixed suspensions with unwanted (gangue) solids, selective flocculation of either the valuable components or the gangue components may be employed depending on which route is more technically and economically viable. Both of these routes have been successfully applied on a commercial scale. More specifically to selective flocculation, the choice of either route would be influenced by the available knowledge of the surface and

Grinding Circuit Selection

The AMAX of Canada Limited Kitsault mine is located approximately 150 kilometers, by air, north of Prince Rupert, British Columbia at the head end of Alice Arm, just east of the southern tip of the Alaskan Panhandle. It is presently only accessible by sea or air, although a road is being constructed by the company which will provide access to Terrace, a commercial centre with a population of about 15,000. The topography is typically coastal mountainous with peaks rising to 2,100 meters around the head end of the inlet. The concentrator is at an elevation of 515 meters with the mine at 630 meters.

Grinding Circuit Design Constraints

The original Kennecott circuit was designed for 5,443 metric tonnes per day (mtpd) or 6,000 short tons. Doubling the grinding circuit capacity was carried out under the following constraints:

  1. Average production to be 10,886 mtpd with equipment sized for variations in work index and throughput.
  2. Rod mill feed to be approximately 80% passing 16 mm (5/8 inch) with all material passing 19 mm (¾ inch).
  3. Cyclone overflow product (rougher flotation feed) to be approximately 40% + 149 microns (100 mesh).
  4. Grinding circuit availability to be 95%.
  5. Bond Work Index of 18 to

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