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By Frank Peterson

THE manufacture of gasoline by extraction or precipitation from the natural gases in which it is found, the present status of. the industry, its past development and future extensions; offer a subject which is so broad that to handle it in its entirety would require a voluminous paper. The writer will, therefore, attempt to concentrate the essential matter of the subject for a general presentation, giving some of the most interesting details of the factors that are important to the industry. This industry has drawn liberally on the principles of physics and chemistry, and, to a large extent, has had to adapt such information as is most useful-not from data recorded with reference to petroleum, but from data recorded with reference to general treatment of other materials. Because of the complex character of the petroleum series of hydro-carbons and the fact that data, such as solubilities, vapor pressures, etc., of the different petroleum compounds have not been determined, we are still working by rule of thumb in. some essential phases of the industry. Furthermore, the difficulties of determining such data are almost insurmountable. We have not one,, but two butanes to deal with-not one, but several, pentanes, hexanes, heptanes, and, as we ascend in the series the complexity and multiplication of isomers increases at such a rate as to make the task of isolating and studying their physical characteristics almost beyond the hope of possible attainment. The industry is the connecting link knitting the interests of oil producers and refiners into a much closer relationship than ever existed .prior to its inception and development. The relation between the producer and the refiner of petroleum prior to 1910 was. a rather antagonistic one in a commercial sense. It was to the interest of the producer of crude petroleum to sell it for a maximum consideration; the refiner's interest was to obtain the same product for a minimum consideration; therefore, each side of the business transaction retained within his own hands as far as possible the trade secrets of his business. Each side maintained an attitude of cold-blooded business sympathy only for the other. Cas-

Jan 12, 1917

By J. Rajala

The Kupol mill facility processed a high grade free milling gold/silver ore containing 28.2 g/t Au, 324.8 g/t Ag and approximately 0.5% pyrite during 2008 operation. Gold predominantly occurs a selectrum in the ore and silver is predominantly present in the forms of acanthite, stephanite, pyrargyrite and proustite. Mill start-up was in mid-May 2008 and the mill reached the design throughput of 3 000 tpd in October. The ore was ground to approximately 70%?53 microns. A Knelson Concentrator recovered 9.8% gold and 0.5% silver. The gravity tails reported to a cyanidation circuit that has 14 hours pretreatment and 116 hours leaching. The slurry from cyanidation was then processed by counter current decantation (CCD) thickening to wash and separate the leach residue from the pregnant leach solution. Precious metals are recovered fromthe pregnant solution using the Merrill-Crowe process. The washed CCD leach residue slurry is treated with calcium hypochlorite to destroy cyanide and then sent to the tailings impoundment. Leaching is performed with a new technology called ?CELP? (CANMET Enhanced Leach Process). The Kupol mill overall gold and silver recoveries for 2008 were 95.4% and 85.6% respectively, which were 2.8% and 7.5% higher than targets. Gold and silver extractions in the leach circuit were 94.2% and 84.5% respectively. Leach profiles indicated that gold extraction reached a plateau in the 4th tank while minor silver dissolution occurred in the 5th tank. With the CCD circuit included, total gold and silver extractions increased to 95.4% and 86.6%, respectively. Optimization of the leaching strategy made it possible to reduce sodium cyanide concentration to as low as 410 ppm without compromising precious metals extractions. Silver was effectively leached from the refractory silver minerals because CELP produced more oxidized mineral surface relative to the conventional cyanidation leached mineral surfaces. The average cyanide consumption for 2008 was 1.3 kg/t. The new leaching technology proved to be very robust and performed efficiently even with changes in feed grade and ore mineralogy. Laboratory experiments produced results that were indicative of plant performance. The robustness of the technology and the laboratory test work contributed to the success of the Kupol mill start-up.

Jan 1, 2009

By R. A. Pyper, J. L. Hendrix

Laboratory leaching experiments were conducted to ascertain the effectiveness of acidic solutions of thiourea, CS(NH2)2, for dissolving gold from finely disseminated gold ores. The ore tested was from the Chipmunk ore body of the Northumberland mining district in Nye County, Nevada, USA. Extractions of up to 90% were attained from the ore. Extraction was shown to be dependent on thiourea concentration, ferric sulfate oxidant concentration, acid concentration, and leaching time. Optimum conditions were an ambient temperature leach near pH 1.0 utilizing 100 to 200 kg/ton thiourea and 50 kg/ton ferric sulfate for 8 to 24 hours.

Jan 1, 1981

By R. A. Pyper

Laboratory leaching experiments were conducted to ascertain the effectiveness of acidic solutions of thiourea, CS(NH2)2, for dissolving gold from finely disseminated gold ores. The ore tested was from the Chipmunk orebody of the Northumberland mining district in Nye County, Nevada, USA. Extractions of up to 90 percent were attained from the ore. Extraction was shown to be dependent on thiourea concentration, ferric sulfate oxidant concentration, acid concentration, and leaching time. Optimum conditions were an ambient temperature leach near pH 1.0 utilizing 100-200 kg/t thiourea and 50 kg/t ferric sulfate for 8 to 24 hours.

Jan 1, 1981

By Peng Lv, Shiqian Liu, Bin Xu, Qian Li, Yongbin Yang, Tao Jiang

The treatment process of a low-grade refractory gold ore containing sulfide minerals and carbonaceous matters was studied in this work. The gold extraction of this ore by all-sliming cyanidation was only 11.75%. Hence, a pretreatment was necessary. In this paper, a flotation-preoxidation-cyanide leaching process was developed. The concentrate from the flotation procedure was processed using different preoxidation methods. A concentrate containing 34.08g/t of gold with the gold recovery ratio of 81.20% was obtained by flotation. After roasting, microwave heating or alkaline pressure oxidation, the gold cyanidation ratio reached 82.37%, 81.26% and 71.09% respectively. Roasting was an effective, reliable and mature technique to oxidize sulfide minerals and carbonaceous matters. Roasting and microwave heating both produced dangerous environmental pollutants while alkaline pressure oxidation was eco-friendly.

Jan 1, 2015

By Yan D. S

The removal of antimony from a refractory gold-bearing stibnite ore by roasting and selective chlorinating roasting was investigated. The influence of roasting temperature, roasting time, roasting atmosphere and type and amount of chlorinating agents on antimony removal were studied. The laboratory studies carried out included roasting tests of 4 g samples in a laboratory rotary kiln, followed by 400 g samples roasted in a fluidised bed. The test results revealed that antimony was efficiently removed by roasting at temperatures over 800¦C in a nitrogen atmosphere. The most efficient volatilisation of antimony was achieved with the addition of ferric chloride at temperatures between 350-600¦C.

Jan 1, 1995

By Davis A, Song J

A review of the literature indicated that several studies have been reported on the dissolution of gold using iodide/iodine, bromide/bromine leaching systems. Although the reagent costs are much cheaper for chloride/chlorine (or hypochlorite) this system has not been fully evaluated. This study was conducted to evaluate the fundamental chemistry of the chloride/hypochlorite leaching system. The CHEMIX program was used to model the stability of various gold species existing in the solution. The gold dissolution rate at different conditions was determined using gold strips immersed in various mixtures of chloride/hypochlorite. Leaching experiments were conducted to test the extraction of gold from various ores (oxidised and copper-gold ores), showing a promising prospect for this technique in various applications.

Jan 1, 1992

By Luis G. S. Sobral, Gabrielle N. Bard

Copper sulphides Concentrates, from the flotation process of copper primary ore; contain, commonly, small amounts of precious metals, such as gold and silver. During the smelting process of those concentrate all gold and silver are practically in the blister copper, which is cast into anodes. Those copper anodes are electrorefined in an electrolytic system, where the electrolyte is an acid copper sulphate solution, where a high purity electrolytic copper is produced (>999,9/1000). The slime when submitted to an oxidative leaching process, using sodium hypochlorite and hydrogen peroxide as oxidizing agents, turn those metals into solution. This research practical work, apart from concentrating effort on the digestion of the anode slime, aims at evaluating the efficiency of the cementation process of the metals of interest for the separation of them to take place. 141

Jan 1, 2008

By Peter Fischer

Reducing mining costs has become such an important factor in the German coal industry that operators are forced to work only those areas where production costs can be kept low. These areas will normally be located close to the mine shafts because they are easily accessible. Even the shaft pillar is now being considered as part of the winning zone. Before working coal in shaft pillar zones it is essential to assess the impact this will have on the shaft lining. There is a huge difference between sliding and strata-anchored shaft systems. However, if the overburden comprises lightweight soil both types of shaft will have a tendency to protrude from the surrounding ground. This paper presents the geomechanical reasons underlying this reaction and the methods used for predicting and measuring it.

Jan 1, 2007

By Chr. Kersch

This project further develops supercritlcal fluid extraction as an industrial soil remediation process. Heavy metals are removed from sand using CO2, The effect of the type of complexing ligands, pressure and water content on the extraction efficiency is investigated.

Jan 1, 1999

By N. Melnyk, H W. Habgood

The conventional low temperature process for extracting' helium from natural gas involves liquefying the whole gas stream in order to remove the relatively small fraction of helium. A process based on the selective diffusion of helium through a semi-permeable barrier is, in principle, more economical and flexible, particularly for the treatment of small re-serves and low concentrations. The well-known permeability of glass to helium offers the possibility of such a diffusion process and McAfee of the Bell telephone Laboratories showed in 1958 that practical separations could be achieved by passing natural gas over bundles of fine capillary glass tubing. Developmental studies have been carried out involving larger units and more extended field tests than those of McAfee. Fine capillary tubing of Pyrex glass 0.0035 in. diameter was prepared by drawing ordinary 6 mm. laboratory tubing in a furnace. Extraction units were pre-pared containing about 10,000 such tubes, 4 ft. long and cemented inside

Jan 1, 1961

By Jun Chang, Jin-hui Peng, Jing Chen, Li-bo Zhang

The leaching of indium from refractory zinc oxide flue dust(ZOFD) is attempted to utilize microwave sulfating roasting process, followed by water leaching. The ZOFD and roasted product were characterized by XRD and SEM/EDS analysis. The effects of various roasting parameters, such as roasting temperature/duration, the proportion of sulfuric acid, as well as the leaching parameters such as the leaching duration and liquid/solid ratio, were assessed. The results indicate that nearly 97% of indium could be leached under the following conditions: mass ratio of concentrated sulfuric acid to ZOFD to be 0.5, roasting temperature of 150 ℃ and duration of 1.5 hours; while the optimal leaching conditions hold at temperature of 25 ℃ for 1 hour, with 4:1 of liquid/solid ratio. The indium leaching rate by the microwave roasting increased by 8% as compared with the conventional roasting process under identical conditions.

Jan 1, 2015

By S. M. C. Santos

Preliminary bench-scale studies were carried out on the leaching of a zinc sulphide concentrate from Somincor, Portugal, and the purification of the resulting pregnant solution using solvent extraction techniques. The sulphide concentrate contained 36% Zn, 36% S, 2% Fe and 4% Cu. The leaching was carried out with sulphuric acid in the presence of ferric sulphate as the oxidant. Important leaching parameters, such as the effect of reaction time, the solid-liquid ratio, temperature and concentrations of acid and oxidant, were investigated. After leaching, the recovered solution was contacted with an organic phase containing Acorga 5640 to remove the copper. Subsequently, the removal of iron from the leaching solution was achieved with a mixture of Cyanex 272 and TBP. This solvent mixture was relatively selective for iron over zinc. The stripping of the loaded solvent was performed with 200 g/L H2SO4. Six countercurrent extraction stages achieved a separation of about 99% of the iron from the leaching solution. The iron-free leachate can be further treated to recover minor metals by cementation, and finally, zinc by liquid-liquid extraction. The advantages of the suggested process relative to the traditional jarosite process are discussed.

Jan 1, 2006

By Edilson Marques Magalhães, Danielly Da Silva Quaresma, José Antônio da Silva Souza, João Nazareno Nonato Quaresma, Emanuel Negrão Macêdo

"The production of alumina from bauxite using the Bayer process generates the residue known by red mud. This material can be used as a source for concentration and recovery of valuable metals such as titanium. The greatest difficulty of concentrating titanium compounds is the large amount of iron oxide present in red mud > 30% by weight. This paper shows the extraction of the iron oxide, increasing the concentration of the titanium compounds. The red mud is leached with H2SO4 at 30% concentration and temperature range of 60°C, 80°C and 90°C. Analysis of the leached and concentrated was made to verify the effectiveness of the iron oxide extracting process and the titanium compounds concentration viability.2- IntroductionIn the state of Para is located the Industrial Unit Alumina of North of the Brazil S/A (Alunorte), created to produce and commercialize alumina, aluminum oxide, Al2O3. The ALUNORTE with Aluminum Brasileiro S/A (Albras) and Mining Rio do Norte S/A (MRN) complete the production cycle of aluminum in the state. Although the production of alumina has a importance great for the socio-economic status, as in any area other, generates a amount large of waste, thus causing environmental impacts. Pará State has produced 25 million tons of bauxite (Pinto, 2010), of which 60% were transformed into alumina plant in Pará and Maranhão by ALUNORTE by ALCOA, generating approximately 9,000,000 tons of waste known as Red Mud (RM). Due to the high reactivity this material is considered dangerous, and currently there is no operating process capable of reuse all the material produced at any refinery. The search for industrial processes in order to reuse these wastes can contribute to reducing the overall impact of the production process of alumina. In this context, this paper estudied, within the research line of Solid Waste valorization the mining industry and metallurgy, a process that makes possible the red mud as a source of raw material, in other words, seeks to maximize the use of red mud as raw material for concentration and or recovery of titanium compounds in both the crystalline form of anatase, rutile and ilmenite, avoiding the predatory extraction of natural resources of these materials. Applying definitely the concept of self-sustainability of the mining industry and metallurgy."

Jan 1, 2012

By Yeonuk Choi, Patrick R. Taylor, Lyle Cunningham

Laboratory experiments have been performed to evaluate the potential for metal removal and recovery from river bed tailings by ferric chloride leaching. The lead, zinc, silver and other metals in the river bed occur due to the old method of dumping mill tailings into rivers. This was practiced prior to the introduction of tailings impoundments. The effects of the leaching method, leaching time, pulp density, ferric chloride concentration, and leaching temperature on the rates and recoveries of lead, zinc and silver were studied. The effects of pulp density and leaching temperature were significant on the extraction rates of lead, zinc and silver. The lead content in the leached tailing was reduced to 0.023 percent, when using an 353O K leaching temperature and 0.384 g of FeC13/1 g of sample.

Jan 1, 1992

By Mike Dry

Conventionally, lithium-bearing brines are processed via solar evaporation, chemical purification, and either electrolysis to lithium hydroxide or precipitation of lithium carbonate. Lithium-ion battery technology and electric vehicles are forecast to greatly increase the demand for lithium, but not all lithium-bearing brines are amenable to the conventional extraction process and new approaches are being developed. The chemistry associated with conventional lithium extraction is outlined and two new approaches are discussed.

By Reuben B. Ellestad, Fremont F. Clarke

In the early days of the lithium industry most of the production was from lepidolite, zinnwaldite, and amblygonite. Nearly all the early extraction processes described in the literature involve heating the finely ground mineral with sulphuric or hydrochloric acid. On subsequent water leaching most of the bases present in the mineral (especially aluminum) are dissolved as sulphates. As a result, the leach solution required extensive chemical purification before the lithium could be precipitated as carbonate. Following the remarkable growth of the lithium industry to its present size, zinnwaldite and amblygonite ores must be considered of minor importance only. Attention is now focused on spodumene, abundant enough in North America to be a major source of supply, and there are important supplies of lepidolite and petalite in Africa. The extraction processes described below all apply to spodumene, although several will also operate on other lithium minerals, such as petalite. Base Exchange with Alkali Sulphates: A distinct advance was made with the disclosures of Wadman and von Girsewalt. In these methods the finely ground silicate ore (spodumene or lepidolite) is intimately mixed with an excess of alkali sulphate (usually K2S04) in at least a 1 to 1 proportion, and the mixture was heated to a relatively high temperature. Base exchange results, with the formation of lithium sulphate. A water leach dissolves the lithium sulphate, together with the excess potassium sulphate. Successful operation of this type of process requires very thorough grinding and mixing, as well as careful temperature control. The use of K,SO, is objectionable from cost considerations since purification of lithium carbonate re- quires the use of potassium carbonate, if the K2S04 is to be recovered and recycled. The lower solubility of K,SO, as compared with Na,SO, is also objectionable, since it limits the concentration of the Li,SO, solution to be precipitated by K,CO,. Early laboratory-scale investigation of this process by Lithium Corp. was not encouraging

Nov 1, 1955

By D. B. Dreisinger, H. J. Sohn, J. S. Sohn, G. A. Kordosky

The transport of lithium through a supported liquid membrane was studied with a mixture of D2EHPA and TBP in kerosene as a mobile carrier. In the flat- sheet supported liquid membrane(SLM) system, experiments were carried out to investigate the effects of concentration of mobile carriers in the membrane solution, hydrogen ion in the feed solution, and temperature on the transport of lithium. Experimental results agreed well with a transport model for permeating lithium across the liquid membrane. The permeation rates of lithium can be explained in terms of diffusion of a Li-complex through the membrane phase. For a practical application of an SLM method, a hollow fiber module has been used and lithium can be concentrated more than three times in 24 hours.

Jan 1, 1993

By X. Cai, L. Jiang, G. Fu

A process for recovering manganese from low-grade manganese oxide ore through a reduction acidolysis-selective leaching method is investigated. Two types of biomass, sawdust and straw, were used as reductants. Reduction acidolysis, using concentrated sulfuric acid, was used to disrupt the structure of the biomass, allowing the biomass to be hydrolyzed into monosaccharides. Analysis by X-ray diffraction revealed that Mn2O3 was reduced to MnSO4. Then, in the selective leaching process, iron was removed through the formation of goethite. The optimized experimental parameters are as follows: reductant to ore mass ratio of 0.4, sulfuric acid to ore mass ratio of 0.9, water to ore ratio of 0.5, aging time of 18 h, leaching temperature of 95 °C, leaching time of 90 min, and solution pH of 2.5 to 2.8. Under these conditions and using sawdust as the reductant, the manganese leaching efficiency and iron removal efficiency were 91.8 and 99.2 percent, respectively.

By B. J. Scheiner

Extraction of molybdenum from molybdenite ore by an electrolytic oxidation procedure was investigated by the Bureau o f Mines. Various parameters affecting molybdenum extraction, such as salt concentration, temperature, treatment rate, current density, and particle size, were studied. Molybdenum extraction of 95.2 percent was achieved on a laboratory scale from an ore containing 0.35 percent molybdenite. Corresponding power consumption was 24 kwhr per pound of molybdenum extracted with a base consumption of 4.5 pounds of sodium carbonate. Laboratory and pilot plant experiments are in progress on low-grade molybdenum concentrates containing rhenium and copper. Preliminary results indicate that molybdenum extractions in the 90- to 99-percent range and rhenium extractions of 93 to 99 percent can he obtained without appreciable oxidation of associated copper minerals.

Jan 1, 1972