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Flotation Plant Optimization

A mathematical model was developed for the grinding and flotation section of Union Carbide’s Bishop mill and this model was used to indicate how variations in grind, retention time, and calcite and fluorite content effects the mill capacity, tungsten units produced, and the grade and recovery of the scheelite concentrate. A model such as this is a starting point in determining the economic optimum running condition for a mining and milling operation and an example of this is given.

Procedure & Data

Samples were taken of the sulfide rougher tails, the feed to the scheelite float section, seheelite cleaner tails and each of the tails and concentrates of the 10 scheelite rougher cells in that section. Time-weight samples were taken of each concentrate and the cleaner tails so that mass flows could be calculated. Each concentrate sample was weighed wet, screened wet on a 200-mesh screen, filtered and dried. The dried sample was weighed and pulp densities and mass flows calculated. Figure 1 shows the flotation circuit and the sampling points.

During the sampling period,the flotation procedure was not changed; therefore no information was obtained on many of the flotation variables. The results can be used, however, to indicate how retention time, feed

Fluorspar Agglomeration

This report will be given in two sections. The first section outlines techniques and equipment to form almond shaped fluorspar briquettes by means of briquet presses, and the second section outlines techniques of the balling disc.

Briquet Presses

Fluorspar has been briquetted for a number of years and the so called “peach pit” briquet is known to many steelmen. Present production is estimated at over 100,000 tons annually. Slide 1 shows an assortment of various sizes and shapes of briquettes. It is possible to form fluorspar into almost any configuration of briquet. For safety on the melting floor, pillow type briquets are preferred. Ease of mechanical handling and durability of the product are facilitated by an almond shape. The dimensions of the almond can vary from 1-in. to 1-½-in. in length, from 13/16-in. to 1-in. in width and from ½-in. to 1-in. in thickness.

A wide variety of pillow shapes are available. Briquet presses can be supplied that permit changing from one size briquet to another. Since steelmen prefer different briquet shapes, the product can be changed simply by changing the briquet dies thus allowing one machine to supply several mills. Briquetting of fluorspar is accomplished at room temperature with the

Leaching of Copper by Fungi

Bacterial and fungal populations were observed in samples taken from the White Pine Copper Company tailing pond and mine, and isolates were prepared of the dominant species. The isolates were then screened for solubilization of copper from tailing, ore, and concentrate during incubation in a carbon and nitrogen supplying medium. Certain Penicillium fungi solubilized significant amounts of copper under neutral to slightly acidic conditions. Leaching apparently was accomplished by release into the medium of metabolites which chelated with the copper. The process was found to be highly dependent upon the medium and the concentration of copper in the source material.

Methods

The White Pine tailing disposal area covers about 1700 acres adjacent to the plant; the holding pond takes up about 150 acres. The samples were sealed in sterile one-half pint glass jars and refrigerated at 4° C. until they could be plated within the following 24 hours. After

leaching of copper sketch plan

vigorous shaking of the sample jar, one milliliter of fluid and suspended solids was pipetted into a sterile petri-dish and 25 milliliters of agar medium at 48° C. was added. The contents were mixed by swirling, and after the mixture hardened

Large Particle Flotation in Shallow Air Cell

The theoretical requirements for the flotation of large particles are discussed. A flotation machine is described which has components which meet many of the theoretical requirements for the flotation of large particles. The machine’s salient features include multiple fine-bubble attachment, froth level feeding, quiescence, shallow depth, and short flotation time.

Theory

Flotation is generally considered to be a process whereby a relatively large bubble becomes attached to a relatively small particle or a group of relatively small particles. The flotation of larger particles in general (and with the shallow air cell in particular) can be considered to be a process whereby a relatively large particle becomes attached to a group of relatively small bubbles. This theory has been supported by a number of investigators.

In addition, within limits, it has been stated that smaller bubbles will be more effective for the flotation of larger particles. More tenacious bubble-mineral attachment is made when large contact angles between bubble and mineral are present and the contact angle is increased as bubble size is decreased.

According to Klassen, the largest magnitude of the force of the collision occurs with the largest difference in the dimensions cf the bubble and the mineral particle. For a

Kelex 100 Reagent for Copper Solvent Extraction

Kelex 100 is a single organic compound designed to selectively extract copper ions from leach liquors having acidities in the pH range of one to three. In the process of extraction, as indicated by the forward direction of the following equilibrium expression, an extremely stable copper complex is formed.

solvent-extraction-equation

The unusual stability of [R2Cu] org in the above equation forces the reaction to the right, permitting the reagent to function well at low pH.

Reversal of the above equilibrium by contacting the copper-loaded organic phase with an aqueous strip solution containing 120 to 150 grams per liter sulfuric acid can produce a concentrated copper sulfate solution of sufficient ionic purity to serve as feed to electrolysis .

The Ashland copper reagent, Kelex 100, has been evaluated at several different levels of concentration in kerosene and in an aromatic 150 petroleum solvent, the latter having a flash point of 150°F and a distillation range of 370°F to 410°F. The extraction characteristics are the same in both solvents. The maximum loading capacities of 5% and 2.5% solutions are 4.0 gpl and 2.0 gpl Cu, respectively.

The relative degree of extraction of cations other than copper can vary substantially

Jet Pulverization

Jet pulverization is a relatively new tool for fine grinding. It is not yet in general use in the mining and ore dressing fields, since most of the requirements in these areas have been for relatively coarse particle sizes. As the need for finer grinding increases – because of different ores, new products, and new values being sought – jet pulverization will, increasingly, be properly used.

Jet pulverization involves size reduction by impact of particles at high velocity against other particles or against a target of some sort. Energy is imparted to the particles, initially, by gas or vapor which has been expanded through nozzles to high velocity.

As in all size reduction systems, efficiency of operation and control of product requires prompt classification following the application of energy. Jet pulverization is nicely suited to air classification, and the upper portion of  The product size is controlled, by the amount of fan air introduced at the bottom of the classifier, and by the rotational speed of the classifier.

For most mineral-type materials, with no special problems, a product size specification in the range of 99% -200 mesh or so represents the point where the overall cost per ton will be equivalent for jet

Hydrometallurgical Investigation of a Complex Mineral Mixture

Separation of valuable constituents from a complex mineral mixture was examined. Nitric acid leaching produced a solution containing copper, zinc, iron and a large proportion of silver. The residue contained antimony, lead, the remaining silver and elemental sulfur. A caustic sodium sulfide leach dissolved the antimony from the residue, producing an insoluble, high-grade silver-lead product and a filtrate for electrolytic recovery of antimony. The pH of the primary filtrate was raised, precipitating the iron and leaving a solution containing the copper, zinc and the soluble portion of the silver, which would be recovered by conventional means.

hydrometallurgical-chemical-analysis

For a differential separation from leaching, some of the sulfides contained in the mineral mixture needed to be converted to soluble forms by oxidation. In a previous study, sulfuric acid leaching was examined using perchlorate and air at elevated pressures for oxidation. However, satisfactory dissolution of values did not result from this treatment. Preliminary testing with nitric acid indicated that it might be a useful solvent in this investigation. Reasons for favoring nitric acid are: (a) it is a powerful oxidizing agent, (b) nitrous oxide gas produced removes other reaction products from mineral surfaces, (c) high temperatures

Hydrofracing Mining

Hydraulic fracturing was developed as a method of stimulating production of oil from oil producing formations. The primary paper by Clark in 1949, describes the process of placing a hydrostatic pressure of sufficient strength on the producing formation of an oil well that the rock apparently cracked, and then, on allowing the well to flow back, a higher rate of recovery of oil was enjoyed.

Horizontal Fracture Field Experiments

Our first detailed study of horizontal fracturing possibilities was done in the Sacatosa Field, Maverick County, Texas. The oil horizon in this field was a tight well consolidated sandstone, average porosity of 23%, but with a permeability of 0.1 to 10 milidarcy and median value of 2.3 milidarcy. This was much too low to yield an economical quantity of oil. The depth was only 1,000 to 1,500 feet. It was proven that large horizontal fractures would increase the productivity. The geology and core data were presented at the Society of Petroleum Engineers Meeting, October, 1960.

The Natural Gas and Gas Products Division of Conoco needed inexpensive storage near to their pipe line complex running out of the Western Oklahoma gas fields. A convenient location was found near Medford, Oklahoma, which was the

Rock Fracturing Techniques for In-Place Leaching

The two most stringent parameters for in place fracturing of rock are the lack of any initial void space in the rock which to expand into and the ability to gain access only through drill holes. These two restrictions have proven so severe that as of today the only proven techniques for efficient fracturing are the contained nuclear detonation and hydrofracing. Both of these methods have highly developed technologies for their application.

In contrast to the high pressure explosions, hydrofrac pressures are only equal the static overburden stress. The cracks are formed either by overcoming the tensile strength of the rock or by fluid penetrating along on a pre-existing break. Cracks continue to propagate as long as fluid pressure is maintained above overburden. Fracture connections between wells spaced as much as one half mile apart have been reported.

Thus, the ideal fracturing mechanism appears to be a system of high volume but reasonably low pressure fluid injection. Two schemes for accomplishing this are under investigation by myself and others at New Mexico Tech. The simplest concept is a simple liquid oxygen and kerosene burner, the fuel and oxidant being transported down the borehole in liquid form and ignited on bottom.

Leaching of the

Hydraulic Mining Techniques

The practice of transporting an ore or matrix from a pit area to the plant process area by means of a hydraulic pipeline has long been used by the mining industry. The industries which have classically used hydraulic transportation of ore to the plant include the phosphate mining industry, the heavy minerals mining industry, the clay mining industry, and the sand mining industry. As the advantages of this method become better known throughout the mining industry as a whole, and as techniques and expertise improve, its use will undoubtedly spread.

The widely recognized advantages of hydraulic transportation of ore from the pit area to the mines are:

  1. Its relatively low initial capital costs.
  2. Its speed of relocation at the mine site.
  3. The washing and scrubbing action given to the ore by its hydraulic passage into the pit pump and the subsequent trip through booster pumps down the pipeline to the plant.

The average hydraulic mining pit in use today consists of a dragline used for removing the matrix from its in situ location and depositing it in a well or pit. Around this pit are stationed high pressure hydraulic monitors which are used for the dual purpose of slurrying the material in

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