AU2017310348B2

AU2017310348B2 - Method for extracting organic carbon and/or bitumen from ores of metal sulfides or polymetal sulfides

Info

Publication number: AU2017310348B2
Application number: AU2017310348A
Authority: AU
Inventors: Juan Francisco SCHWARZE FRAILE
Original assignee: Individual
Current assignee: Individual
Priority date: 2016-08-11
Filing date: 2017-09-05
Publication date: 2021-03-04
Anticipated expiration: 2037-09-05
Also published as: CL2016002035A1; CA3032773C; WO2018027334A1; CA3032773A1; AU2017310348A1

Abstract

The invention relates to a pretreatment or process prior to ore flotation, which allows the total or partial extraction of bitumen or other organic elements that form part of the ore and which interact negatively with the flotation process. The pretreatment consists of mixing the ore with water and adding a strong base. Following a period of agitation and bubbling, the organic elements are separated, said elements rising to the surface owing to the hydrophobicity thereof and being removed. Ore particles of economic interest are also removed together with the organic elements. For this purpose, cleaning steps that allow the ore to be returned to the process are considered. When the pretreatment is complete, the ore has a lower content of organic elements, which facilitates the ore flotation process and improves the indicators thereof: recovery, concentrate grade, and use of reactants.

Description

DESCRIPTION

This invention considers a method for pre-treating bituminous copper ore that leaves the grinding mill. This pre-treatment consists of the addition of sodium hydroxide (NaOH) in doses between 0.5 and 5 kg/t of ore, a conditioning stage, a primary separation stage, and one, two or three secondary separation or cleaning stages, getting two products: a rich in bitumen slurry to be discarded, and a poor in bitumen slurry that feeds the flotation of copper. The cleaning stages are necessary because, together with the bitumen, copper ore particles are mechanically dragged, which must be recovered by returning them to the previous upstream stages. This pre-treatment improves the technical indicators of flotation (recovery, concentrate grade, reagent consumption and residence time).

The process begins with the Conditioning Stage, where slurry from the grinding feeds an agitated reactor. In this reactor, sodium hydroxide is added in a dose that can vary between 0.5 and 5 kg of ore. The residence time in this stage is in the range between 5 and 60 minutes.

Then, slurry feeds the Primary Separation Stage, which is carried out in agitated reactors with air bubbling. The bubbling causes the bitumen to rise to the surface. By overflow, a rich bitumen slurry (primary concentrate) is extracted. The residence time at this stage is 5 to 40 minutes. The tail of this stage is an ore low bitumen content slurry that feeds the flotation.

The primary concentrate feeds the First Cleaning Stage, which is carried out in series-connected, air-bubbling agitated reactors. The bubbling causes the bitumen to rise to the surface. By overflow, a pulp is extracted with higher enrichment in bitumen and lower enrichment in copper (first cleaning concentrate).The residence time at this stage is 5 to 30 minutes. The tail of this stage is returned to the Primary Separation Stage.

The concentrate from the first cleaning feeds the Second Cleaning Stage, which is carried out in agitated reactors with air bubbling, connected in series. The bubbling causes the bitumen to rise to the surface. By overflow, a pulp is extracted with even greater enrichment in bitumen and lower enrichment in copper (second cleaning concentrate). This concentrate is discarded. The residence time at this stage is 5 to 25 minutes. The tail from this stage is returned to the First Cleaning Stage.

The reactors used for this invention are usual reactors of the industry. Conventional flotation cells, columnar flotation cells, pneumatic flotation cells, foam mixer-separators, or any other equipment that performs a similar function can be used. The agitation of the pulp can be mechanical or pneumatic. Air bubbling can be achieved by air injection or by self-aspiration. As a result of the mechanical drag, part of the copper content of the pulp comes out together with the bitumen concentrate at each stage. Therefore, the number of cleaning stages will depend on the nature of the agitated reactors selected, and it may be higher or lower than the two stages indicated in this description.

The efficiencies for each stage, based on experimental evidence, are shown below:

Stage Solid drag, Copper drag, Bitumen % % extraction, %

Conditioning - -

PrimaryStage 15-25 15-25 85-95 First Cleaning 50-60 5-050-60 75-85 Stage Second Cleaning 50-60 5-050-60 75-85 Stage Pre-treatment 2-6 2-6 80-85 (Global) Copper Flotation 92

Global 85-90 1

Experimental tests show that the bitumen extraction levels achieved lead to flotation copper concentrate recoveries and grades like those obtained with ores with low or no bitumen content.

A comparison of the processing of bituminous copper ores, with or without treatment, is shown below:

Cu NaOH, Pre grade in kg/t treatmen Frother, Flotation recovery concentr t time, g/t time, min ate, % min Nopretreated 82 22 -- -- 200 25 ore Pretreated 85-90 26-28 1-5 25-40 50 15 ore

Because temperature accelerates the reaction, the implementation of the process at the industrial scale could consider the installation of thermal insulation in pipes and reactors to take advantage of the heat generated in the grinding stage. The higher the temperature, the kinetics accelerate and the consumption of sodium hydroxide decreases.

Another possible optimization for some minerals is to add sodium hydroxide in the grinding, reducing the residence time in the conditioning. This stage may not even be necessary. It is also possible to use a strong base other than sodium hydroxide, such as calcium hydroxide (Ca(OH)2) (0.5 to 5 kg) or calcium oxide (CaO) (0.5 to 7 kg/t). The required doses should be studied for each type of mineral.

The increase in copper recovery has a positive effect on the income that can be achieved by the mining company that treats these minerals. Increased concentrate grade reduces concentrate and smelter transportation costs. The reduction in frother consumption implies savings of this input, additionally to the operating issues due to excessive froth presence in downstream processes.

LATEST APPROACH: The bibliography related to metallic sulfide ores containing bitumen or pyrobitumen as an impurity is limited, mainly geological and mineralogical 85 studies (Ref.[1], [5], [6], [13], [14], [15], and especially [12]). Regarding the process for these minerals, I found the following:

• Addition of flotation reagents (foaming agent, collector) in excess: three, four or more times as usual in industry. As an example, in a mine where I 90 worked years ago, the frother dosage was 100 g/t, sometimes even 200 g/t, when the normal dosage is 20 to 30 g/t in the industry. A similar example I found in Australia (Ref. [8]). Despite adding excess reagents, metal recovery is low, and flotation selectivity also.

95 • I found another approach to the issue. A group of Polish researchers (Ref.

[2], [3], [4], [9], [10] and [11]) studied the elimination of bitumen using sulfuric acid. They apply this pretreatment to the primary (rougher) copper flotation concentrate. Since rock contains many carbonates, acid consumption is exceptionally high (200 to 400 kg/t). This pre-treatment has 100 been laboratory and pilot-tested. As far as I know, there is no industrial application of this method.

The method I propose is different, and it is the removal of the bitumen contained in the ore using techniques inspired by the oil sands industry, and whose first 105 patent, from which all the others derive, was filed in Canada 90 years ago (Ref.

[7]).I demonstrated through laboratory tests that the ore has a better performance in flotation improving its indicators of recovery, purity of concentrate and reagent consumption after a bitumen cleaning. I also demonstrated that the fraction of copper that comes out together with the 110 bitumen is not physically or chemically bound to it, and therefore it is possible to recover it in successive separation stages.

BIBLIOGRAPHIC REFERENCES 115

[1] Budyaka, A. E., Goryachevb, N.A., Razvozzhaevaa, E. A., Spiridonova, A. M., Sotskayab, 0. T., y Bryukhanovaa, N. N. (2015) "Geochemistry of Dispersed Organic Matter in Gold-Ore Deposits of Black Shale Formations", Doklady Earth Sciences, Vol. 463, Part 2, pp. 847-850. Russian Original in 120 DokladyAkademiiNauk, Vol. 463, No. 6, pp. 692-695

[2] Chmielewski, T, Luszczkiewicz, A, Konopacka, Z, (2008), "Acidic pretreatment of hard-to-tread copper ore flotation middlings to facilitate flotation efficiency", en Wang, D. D., Sun, C. Y., Wang, F. L., Zhang, L. C., y Han, L., "Proceedings of XXIV International Mineral Processing 125 Congress", Beijing, vol. 3, p. 1189-1200

[3] Chmielewski, Tomasz, Konieczny, Andrzej, Kaleta, Rafal, y Luszczkiewicz, Andrzej (2014), "Development concepts for processing of Lubin-Glogow complex sedimentary copper ore" en "Proocedings of XXVII International Mineral Processing Congress", Santiago, Chile 130 [4] Chmielewski, Tomasz (2015) "Development of a Hydrometallurgy for productino of metals from KGHM PolskaMiedz S.A. concentrates", Physicochemical Problems of Mineral Processing, vol. 51(1), p. 335-350

[5] Cisternas, Maria Eugenia, Frutos, Jos6, Galindo, Eduardo, y Spiro, Baruch (1999), "Lavas con bitumen en el Cretecico Inferior de Copiap6, Regi6n de 135 Atacama, Chile: petroquimica e importanciametalog6nica", RevistaGeol6gica de Chile, v.26 n.2, Santiago, Chile

[6] Cisternas, M. Eugenia, Hermosilla, Juan (2006) "The role of bitumen in strata-bound copper deposit formation in the Copiapo area, Northern Chile", Miner Deposita vol. 41, p. 339-355 140 [7] Clark, Karl, "Canadian patentN° 289058", http://www.ic.gc.ca/opic cipo/cpd/eng/patent/289058/summary.html, as it was read inSeptember 2016.

[8] Gredelj, S.; Zanin, M. y Grano, S.R. (2009), "Selective flotation of carbon in the Pb-Zn carbonaceous sulphide ores of Century Mine, Zinifex", Minerals 145 Engineering 22, 279-288

[9] Luszczkiewicz, Andrzej, Chmielewski, Tomasz, Konieczny, A., Kowalska, M., (2007) "Non-Oxidative acidic treatment of copper sulfide concentrates in the flotation circuit" in del Villar, R., Nesset, J.E., Gomez. C.O., y Stradling, A.W., "Proceedings of Cu2007 - Volume 11 Mineral Processing", 150 Toronto, Canada

[10]Luszczkiewicz, Andrzej y Chmielewski, Tomasz, (2008) "Acid treatment of copper sulfide middlings and rougher concentrates in the flotation circuit of carbonate ores", Int. J. Miner. Process. vol. 88, p. 45-52

[11]Luszczkiewiczl, A., Chmielewski, T. y Konieczny, A. (2012), "Leaching and 155 flotation of concentrate and middlings in flotation circuits of carbonate-Shale copper ores", en "Proceedings of XXVI International Mineral Processing Congress", New Delhi, India

[12]Parnell, J,, Kucha, H. y Landais, P. eds. "Bitumen in Ore Deposits", Springer-Verlag, 1993 160 [13]Wilson, Nicholas S.F. (2000), "Organic petrology, chemical composition, and reflectance of pyrobitumen from the El Soldado Cu deposit, Chile", International Journal of Coal Geology 43, 53-82.

[14]Wilson, N.S.F.; Zentilli, M.; Reynolds, P.H. y Boric, R. (2003), "Age of mineralization by basinal fluids at the El Soldado manto-type copper 165 deposit, Chile: 40Ar/39Ar geochronology of K-feldspar", Chemical Geology 197, 161- 176.

[15] Wilson, N.S.F.; Zentilli, M. (2006), "Association of pyrobitumen with copper mineralization from the Uchumi and Talcuna districts, central Chile", International Journal of Coal Geology 65, 158- 169 170

Claims

CLAIMS THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. Pre-treatment method before the flotation of copper sulfide ore containing bitumen as an impurity, which allows their separation to facilitate the subsequent process of flotation of ore: a. adding sodium hydroxide to the mineral pulp in 0.5:5 Kg/t b. Ore conditioning as a slurry for 15 - 45 min. c. A primary separation stage carried out in agitated reactors, via air bubbling. d. One, two or three successive separation stages, where the copper, which is hydraulically entrained along with the bitumen, since it is not physically or chemically bound to the bitumen, is returned to upstream stages.

2. A method according to Claim 1 wherein sodium hydroxide and/or calcium hydroxide (CaOH) and/or calcium oxide (CaO) is utilized as a strong base in dose ranges of 0.5:5 kg/t of mineral.

3. A method according to Claim 1 wherein bubbling of air or a different gas within the ore slurry to facilitate phase separation after the strong base addition.

4. A method according to Claim 1 wherein it also applies to sulfide minerals where organic carbon is present as pyrobitumen.

5. A method according to Claim 1 wherein the addition of the strong base can be in the ore grinding stage or in a conditioning stage located between grinding and copper flotation.

6. A method according to Claim 1 wherein it may or may not consider the installation of thermal insulation in pipes and reactors to take advantage of the temperature of the slurry after the grinding.