Hydrometallurgy

How to Recover Molybdenum in Oxidized Ore

A study of some variables affecting the recovery of molybdenum from oxidized molybdenum minerals was made. The effects of variations in contact time, temperature, pulp density, particle size, and solvent concentration on the recovery of molybdenum using acid and alkaline solvents were investigated. Chemical analyses, screen analyses and microscopic examinations were made and the presence of important elements determined.

Description of the Ore

Geologically, this ore occurs in the bottom of the Chadron formation sandstone at the disconformity between the Chadron formation and the Pierre shale. Hand samples of the mineral ilsemannite have also been recovered from this deposit. The rock is composed predominantly of silica sand. The bonding material contains the molybdenum minerals and the iron minerals hydrated and otherwise.

The ore sample was stage crushed through 6 mesh and mixed by recombining splits from a Jones riffle. Upon further sampling and analysis it developed that we could cut reproducible (± 0.01% M0O3) samples at 100 gms wt from our minus 6 mesh aggregate.

Experimental Work.

The first sequence of tests were run to determine the effect of roasting on molybdenum extraction. A series of samples was roasted for one hour at temperatures of 100°, 200°, 300° and 400° C

Use LIX-64 Extractant for Copper Pilot Plant Data

Design parameters for scale-up to commercial plants are presented and discussed along with a revised capital cost estimate. The future pilot program is discussed, including minor design changes and the effect of entrained organic on dump leaching efficiency.

Description of The Liquid Ion Exchange Process

In the extraction section, a water-immiscible organic solvent (normally kerosene) containing an organic extractant is contacted with an aqueous solution containing the metal to be extracted. The two phases are then allowed to separate. Interstage pumping of both organic and aqueous is accomplished by employing the mixer impeller as a pump. A variable number of mixer-settler stages and flowrates may be used to achieve the desired recovery and concentration of the metal from the feed solution. After removal of the metal values, the aqueous solution leaving the extraction section is referred to as the raffinate.

The organic phase containing the metal values (referred to as the loaded organic) is then transferred to the stripping section, where the metal values are transferred from the organic phase to an aqueous solution for subsequent treatment, and the stripped organic recycled to the extraction section.

Chemistry of LIX-64

While the exact chemical structure of LIX-64 cannot be disclosed at

Concentration and Separation of Rare Earths from Bastnasite

The separation of pure, individual rare earths from complex ores has presented extractive chemistry with one of its greatest challenges. During the first part of the 20th century, the only technique available for separating rare-earth mixtures was fractional crystallization. In one instance a rare-earth researcher was said to have devoted several years of his life to carrying out 20, 000 successive fractional crystallizations in order to obtain pure praseodymium.

Less tedious column ion-exchange techniques were developed based on pioneering work at the Institute for Atomic Research at Ames, Iowa. Several research organizations extended this work and developed successful ion-exchange processes for producing pure, individual rare-earth compounds. Ion exchange became the standard technique in the rare-earth industry for producing high-purity compounds; however, a desire for increased throughputs and lower processing costs has stimulated interest in other separations techniques to augment ion exchange or, in certain cases, to replace it.

Liquid-liquid ion exchange or solvent extraction techniques possess advantages of high throughput and ease of control and have been exploited to an increasing extent for’metal recovery and separations. Certain of the rare-earth elements have been recovered successfully by solvent extraction, and the technique is potentially capable of economical extension to separation of all of

Chemical Mining

Chemical mining is the in situ extraction of metals from ores located within the confines of a mine (broken or fractured ore, stope fill, caved material, ores in permeable zones) or in dumps, prepared ore heaps, slag heaps, and tailing ponds on the surface. These materials represent an enormous, untapped, potential source of all types of metals. The field of chemical mining, now in its infancy, encompasses the preparation of ore for subsequent in-place leaching, the flow of solutions and ionic species through rock masses and within rock pores, the leaching of minerals with inexpensive and regenerable lixiviants under prevailing conditions of the in-place environment, the generation and regeneration of such solutions, and the recovery of metals or metal compounds from the metal-bearing liquors.

It is not inconceivable that eventually our ore reserves will consist largely of low-grade, refractory, and inaccessible new deposits and low-grade zones near previously worked deposits, caved and gob-filled stopes, waste dumps, tailing ponds, and slag heaps. Chemical mining promises economic recovery from these types of deposits. Before it can come of age, however, a much better understanding is needed concerning its chemical and physical aspects.

Heretofore, this kind of mining has been more or less limited to

Radiation Logging in Leaching Studies

During the recent expansion of precipitate copper production at the Chino Mines Division of Kennecott Copper Corporation, Santa Rita, New Mexico, local studies of the dump leaching process were intensified. As these studies progressed it became apparent that a reliable method for locating leach solutions within the dump was required, since the contact between leach solutions and the copper-bearing material would determine, in great part, the recovery of values. In the past, the problem of determining leach solution contact has been attacked by various methods, including destructive testing (dump dissection), indirect observation (such as chloride or dye tracers), and mathematical or laboratory model studies. These methods have not proved completely satisfactory for the studies now being developed.

Theory

Only three of several available radiation logging techniques are currently in use at Chino.

Natural Gamma Ray Logging

Isotopes of certain elements occurring in nature are inherently unstable, and undergo spontaneous transformation to more stable forms by emission of energy in the form of a ray or particle. The most common naturally occurring isotope which decomposes by readily detectable gamma ray emission is potassium-40. Potassium tends geologically to be concentrated in clay minerals (such as illite), their parent minerals (orthoclase feldspars and micas), and

Hydrochloric Acid Leaching of Iron from Aluminous Clays

Pennsylvania has ample reserves of high-alumina clays which are potential sources of alumina, but many of these clays contain large amounts of iron, which makes them unsuitable for treatment by acid processes.

hydrochloric acid leaching source and chemical analysis

Of all the clay minerals tested, only gibbsite exhibits high acid solubility. Kaolinite, diaspore, and boehmite, which are the major alumina-bearing minerals in Pennsylvania clays, all display alumina losses of 1-2 percent for a one hour hydrochloric acid leach. This leads to the prediction that only 2-5 percent of the alumina in a Pennsylvania clay would be extracted by a hydrochloric acid leach for one hour at 104° C. The difference in acid solubility among the tested clay minerals has been attributed to their disparity in crystal structure.

hydrochloric acid leaching solubility

 

Sulfuric Acid Leaching of Iron from Clay: Tests were performed to determine the effects of pulp density, temperature, acid concentration, and leaching time on the sulfuric acid extraction of iron from a Pennsylvania diaspore clay.

Iron extraction increases with decreasing pulp density. This is due chiefly to the higher acid to clay ratios at lower pulp densities. The

Electrolytic Removal of Iron from Aluminum Sulfate Solutions

A study on the sulfuric acid extraction of alumina from some Pennsylvania ferruginous clays indicated that the published electrolytic method seems to be more efficient than the known chemical methods for removing iron from the leach liquor. The main disadvantages of the chemical methods are the consumption of excessive amounts of reagents and/or the precipitation of prohibitive amounts of aluminum. In the electrolytic method iron is deposited on the mercury cathode, while aluminum is not and remains in solution. This method, however, had been handicapped by the lack of an effective and economical way to purify the contaminated mercury cathode. .

The electrolytic apparatus used in this investigation was designed and constructed to consist of an electrolytic cell and a mercury purification unit. The cell itself was a 600 mls. pyrex beaker with an outlet on the bottom and an inlet on the inside wall for recycling of mercury. The mercury cathode, having a surface area of 53.0 cm² was connected to the power source with a thin platinum wire, and agitated by air bubbling at a rate of about one bubble per second.

The mercury purification unit consisted of two verticle “M” glass tubes, with its lower ends fused separated onto

Dump Leaching

The dump leaching of low-grade copper ores, as an integral part of the open-pit mining operations in the Southwest, has been practiced for the last fifty years and is increasing in importance as one of the major sources of copper. The recent acceleration in dump leaching can be attributed to the greater tonnages of low-grade ores mined and dumped at newer mines as well as resulting from increased stripping ratios at the older mines; to the relatively small investment in leaching facilities per pound of copper recovered contrasted with expansion of milling facilities to recover equal amounts of the metal by raising tonnage throughout; to low labor requirements needed for leaching; to the simple and continuous nature of the process needing little close supervision of trained operators; and, in recent years, to the awareness by the operators that dump leaching is not only an art but also a scientific process dependent on physical, chemical, and biological factors.

Materials and Methods

Samples for analysis of bacteria activity were collected from the mine dumps of the Chino Mine Division, Kennecott Copper Corporation, Santa Rita, New Mexico. All were placed in sterile 8-ounce screw-cap plastic or glass bottles and were returned to the

Manganiferous Iron Ore Chlorination

The chlorination behaviors of pure iron and manganese oxides were investigated by combining a thermogravimetric analysis (TGA) technique with batch-boat roasting followed by leaching. Ferrous and manganous oxides could be chlorinated readily, but, in the absence of a reductant, the higher oxides of both iron and manganese were difficult to chlorinate. Thermogravimetric analysis curves were drawn to illustrate the complexities of the reactions, and the possible mechanisms were discussed. Then three manganiferous materials from the Cuyuna Range of Minnesota were treated by a process involving the selective chlorination of manganese followed by leaching. The results were interpreted in the light of the chlorination mechanisms observed on the pure iron and manganese oxides.

Materials

The pure ferric oxide used in the study was of analytical grade. Magnetite and wustite were prepared from the pure ferric oxide by heating it for one hour at 900°C in a mixture of CO and CO2. For the magnetite a CO-CO2 ratio of 1:10 was used, and for the wustite 1:1 was used. Pure manganous oxide was prepared by decomposing manganous carbonate of analytical reagent grade in a nitrogen atmosphere at 500°C. Manganese dioxide of analytical reagent grade was used as purchased. Manganese tetroxide was prepared

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

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