management of copper pyrometallurgical slags

MANAGEMENT OF COPPER PYROMETALLURGICAL SLAGS 543

IntroductionDuring the last years, due to world-wide economicrecession and a large inventory of stock, copper reached ahistorical value of 0.59 US$/pound in 2001. This fact meantclosing down many important mining companies in theworld, mainly in USA. On the other hand, strongenvironmental restrictions have been imposed on themining activity, and it is expected they will become morerigorous in the future. Thus, companies have been forced toinvest in new technologies regarding efficiency and cleanprocesses. An approach to this new vision was presented inthe last International Conference on Clean Technologies forthe Mining Industry, held in Chile on May 20001.

In most of the cases, investment in new technologies hascontributed to cost reduction as well as to make companiesmore competitive. However, mining and metallurgicalcompanies are facing serious financial challengesworldwide today, and at the same time they must survivewith a wide range of new problems. Thus, miningcompanies have looked beyond technological innovation inorder to improve their operations and, also, they areconsidering now the advantage of total mining resources,making profitable that which was considered wastesbefore2.

In this regards, this project propose to obtain productswith commercial value from slag, one of the more

important waste generated during pyrometallurgical copperextraction. This waste contains interesting amounts ofcompounds with an important commercial value.

The objective of this work is to identify the best-orientedprocess to obtain commercial products, considering slag asa new mining resource with chemical and physicalproperties different from the original copper ores. Theproducts or by-products to obtain are basically: copper,silica, iron oxides, precious metals and some others minorproducts reported by smelter plants.

Currently, slags have been considered as material for roadconstruction or abrasive material for cleaning metallicsurfaces, amongst other uses3. However, this proposal is tosearch for specific products and for particular applications.For example, copper as copper sulphate solution could betransferred to a leaching plant to obtain copperelectrochemically. Iron concentrate, depending on itschemical and physical characteristics, could be incorporatedas part of pellets for iron production. Silica, in spite of itslow price, could be re-used in the smelting plant as flux,and to fix iron oxides in slag. Precious metals such as goldand silver, ever in small quantities, have a market in themedium and/or small-size mining sector. Thus, rather thandisposing of these slags, they can be used taking fulladvantage of their physico-mechanical properties and torecover some value contained in them.

SNCHEZ, M., PARADA, F., PARRA, R., MARQUEZ, F., JARA, R., CARRASCO, J.C., and PALACIOS, J. Management of copper pyrometallurgicalslags: giving additional value to copper mining industry. VII International Conference on Molten Slags Fluxes and Salts, The South African Institute ofMining and Metallurgy, 2004.

Management of copper pyrometallurgical slags: givingadditional value to copper mining industry

M. SNCHEZ*, F. PARADA*, R. PARRA*, F. MARQUEZ*, R. JARA*, J.C. CARRASCO*, and J. PALACIOS

*Universidad de Concepcin, ChileUniversidad de Atacama, Chile

In past years, Chile has been the largest copper producer in the world and for 2002 miningrepresented country average of 10 % of the GDP, accounting for 47 % of the total exportation.

As copper sulphides are the main mining resources in the country, the metal is produced usingthe classical processes of flotation and pyrometallurgical extraction. Seven copper smelter plants,which extends from the northern Atacama desert to the central part of the country produced1,522,000 metric tons of fine copper in 2002, approximately one half of total copper concentrateproduction, with a notorious environmental impact due to the great amount of slag producedduring these extraction steps.

In this work, a global characterization of copper pyrometallurgical slags produced and disposedof in Chile and worldwide is done, and the concept of total project development is considered toexplain the scopes of the study, recovering different compounds and generating new activitiesaround mining.

The presentation is completed with the proposal of various methods and techniques beingdeveloped today in a joint project between smelter plants and the University of Concepcin, withthe support of the Chilean government and mining companies, addressed to generate newmaterials from copper slag. Recovery of copper, molybdenum, precious metals, silica and iron,that is the most abundant component of the slag, are the goals for this research. Metals,commercial compounds, alloys and different forms of iron oxides for steel industry are proposedproducts.

MOLTEN SLAGS FLUXES AND SALTS544

Some previous studies have been considered45. Amongother interesting papers are notable patents reporting flowsheets for specific processes to treat copper slag. In thiscase, the proposal is to establish methods and techniquesfor treating slag produced in Chilean smelter plants as thefirst approach.

Given the high concentration of smelter plants in Chile6,the intensive production of slag causes major trouble intransport and disposal. Then, use of this waste givesadditional value to the mining-metallurgical business whichis much appreciated. Therefore, this project has the supportof Chilean government by the National Commission ofScientific and Technological Research, CONICYT7.

Characterization of slag: the chilean caseSome properties of a typical copper slag are shown in Table I, and it can be observed that air-cooled copper slaghas a black colour and glassy appearance. The specificgravity varies with iron content, from 2.8 to 3.8. The unitweight of copper slag is somewhat higher than that ofconventional aggregate. The absorption capacity of thematerial is typically very low. Granulated copper slag ismore porous and, therefore, has lower specific gravity andhigher absorption capacity than air-cooled copper slag. Thegranulated copper slag is made up of regularly shapedangular particles, mostly between 4.75 and 0.075 mm3.

Slags produced during pyrometallurgical processes havebeen traditionally considered as a waste3. In the case ofcopper extraction processes, it has been estimated that forevery ton/year of copper produced, 2.2 ton/year of slag isgenerated, and approximately 24.6 million ton/year of slagis generated in the world copper production. In Chile,blister copper production is approximately 1.5 million tons,and more than 3.5 million tons of slag are produced everyyear6. Additionally, around 50 million tons of slag havebeen estimated to be historically stocked in this country.

Typical analyses of various copper slags reported byGorai3 are shown in Table II. In this table, slags fromdifferent origins are presented, named: (1) Iranian NationalCopper Industries; (2) Etibank Ergani Copper Plant, Elazig,Turkey; (3) Caletones Smelter Plant, Chile; (4,5,6,7)Various Indian Copper Plants; (8) Kure Copper Slag and(9,10) Copper Queen , Prince, USA.

Recently, data corresponding to the seven smelters plantsoperating today in Chile have been reported6, and they aresummarized in Table III. In this table slag corresponding toflash smelting furnace, Teniente converter, Peirce-Smithconverter, Anode and fire refining furnaces, andreverberatory furnaces are described.

The average composition of final copper slag correspondsto 3040 % iron, 35-40% silica, less than 10 % of aluminaand calcium oxide and copper content is less than 1%,depending on the method used to clean the final slag of thepyrometallurgical process. Eventually, minor amounts ofzinc, molybdenum and noble metals such as gold and silverare presented. Since, final copper slag contain around 1% ofcopper, its recovery from the slag could be economicallyaccepted if no expensive treatments are found, such astechniques mixing pyro and hydrometallurgical processesor concentration by flotation as it has been established insome concentration plants.

Wastes as resources: the total projectdevelopment, a new philosophy

Total Project Development (TPD) is a new holisticapproach for mining, where the project is not an isolatedoperation, but is part of a wide and multi-activity regionaldevelopment. Under this concept, every extracted materialis considered for constructive usage, establishing a range ofeconomic activities in this way. Waste rock, mine tailings,excess mine water and even industrial garbage areconsidered part of the resource, and as raw material for avariety of downstream ancillary industries2. Even when thisconcept has been applied mainly to tails from concentrationplants89, its philosophy is valid for slag recovery, which isthe objective of this research.

The concept of TPD are from initial research to recyclingof mine tailings. Thus, TPD investigated the feasibility of

Property

Appearance Black, glassy, more vesicular when granulatedUnit weight 28003800 (kg/m3)Absorption 0.13 %Bulk density 144162 lbs per cubic footConductivity 500 s/cmSpecific gravity 2.83.8Hardness 67 MohMoisture < 5 %Water soluble chloride < 50 ppmAbrasion loss 24.1 %Sodium sulphate 0.90 %soundness lossInternal friction angle 4053

Table IPhysical and mechanical properties of a typical

copper slag, from3

Origin Fe % SiO2 % CaO % MgO % Al2O3 % S % Cu % Co mg/kg Mn mg/kg Ni mg/kg Zn mg/kg

1 44.78 40.97 5.24 1.16 3.78 1.06 - - - - -2 39.65 31.94 3.95 2.82 2.4 - 1.01 1040 420 150 72203 41.53 37.13 - - - 0.11 0.79 - - - -4 47.8 29.9 - - - - 0.7 - - - -5 44.7/47.7 28.5-32 1.63.9 - - 0.30.9 0.50.95 Tr -8 - 1420 170028506 47.13 - - - - 1.47 0.68 2200 300 500 5007 44 28 - - - - 0.6 1300 - 600 -8 47.8 26.1 0.7 1.0 6.8 1.5 0.82 4000 - - 15009 44.8 (oxide) 24.7 10.9 1.7 15.6 0.28 2.1 - 4000 (oxide) - -10 34.62 (oxide) 27.16 17.42 3.51 14.7 0.33 1.64 - 4900 (oxide) - -

Table IIChemical compositions of typical slags, from3


stand-alone tailings recycling within mining operations, andit incorporated metal retrieval, decontamination andphysical utilization including underground backfill,embankments and sealants, infilling of open-cut voids, andproduction of construction materials for mine use. Theresidue is amended for use as topsoil replacement in minerehabilitation and landscaping2.

Total Project Development is desirable for technical,political, social and environmental aspects, and there is nodoubt that every party associated with such a TPD schemebenefits; the mining company, regional and nationalgovernments, local community, environment andultimately, the global community.

The mining company benefits from additional revenuethrough the retrieval of metals and minerals. Operationalexpenses are reduced for maximum utilization of tailingsand others kinds of wastes. Mining and rehabilitation costsare considerably reduced with the removal of solidsgenerated during the process. The long-term risks ofpotential liabilities from tailings dams and waste dumps arealso removed. Relationships with local communities arevastly improved with the close co-operation associated withTPD, like those with regulatory bodies and environmentalagencies, with the major knock-on effect of improving theprospects of obtaining future leases, permitting and fundingfor subsequent projects.

Since reduced environmental impact, diversity ofassociated industries, alternative employment opportunities,intermediate technologies, range of products and long-termpost mining land-uses associated with TPD arefundamental for sustainable regional development, the TPDapproach, especially in the Third World, offers to themining industry a future compatible with social andenvironmental needs, aiming for sustainable development.

In Chile, the application of TPD approach will help tosolve directly a real problem in the mining andmetallurgical industry today, which is the transport anddisposal of the slag. There are around 50 million tons ofslag already accumulated in the country, and there insufficient areas for disposal close to smelter plants. Thus,the approximated 4 million tons of slag generated per year

in Chile causes an increase in cost of transport, due to thelonger distances to cover. Therefore, any additional valuefor this waste will enhance the interest in developing newprocesses.

Recovery of byproductsChilean experienceSome experiences on recovery of products contained in slaghave been developed in Chile as well as worldwide. As aprimary copper producer, the main objectives of Chileanplants have been focused on copper recovery only,explained later. In fact, all Chilean smelter plants have theirown processes, in use, most of them associated topyrometallurgical techniques6. Among Chilean experienceson this subject, the following can be mentioned:Slag stabilization in asphalt baseThis is a project developed by Sociedad Minera PtreosQuiln, and the main idea is to use sand, refractory materialand smelting slag for asphalt manufacture in order not todispose of the slag near rivers and damp, avoiding thecontamination by heavy metals always present in slag andthe susceptibility of dissolution into underground waters.Thus, neutralization of slag by using it in an asphalt matrixhas been considered a good solution10.

Slag cleaning by coal reductionIn this process the slag produced by the Teniente Converteris transfered to a cleaning slag furnace (HLE), andpulverized coal is injected maintaining the slag temperatureby means of oxygen-fuel burners. The coal reduces thecontent of magnetite in the bath, decreasing slag viscosity,and copper particles are released forming a rich coppermatte (70% Cu) that is returned to the Peirce SmithConverter11.

Slag cleaning in an electrical furnaceIn this process copper is recovered by direct electricalreduction of magnetite, releasing the suspended inclusionsallowing co-reduction of cuprous oxide. The current

Chemical analysis (%)Slag cleaning* Slag weight (t/d) Copper Fe (total) Fe3O4 SiO2 SSlag Production 13,000Flash Smelting Furnace 1,488 3. 23 - 11.8 27.7 3.57Teniente Converter 7,358 7.4 9.4 18.1 26.1 2.37Peirce-Smith Converter 1,402 13.3 41.1 28.4 18.9 0.79Anode and Fire Refining Furnace 408 40.3 28.9 11.0 11.1 0.82Reverberatory Furnace 2,344 0.94 38.3 7.0 32.8 0.99Slag Cleaning 9,039Reverberatory Furnace 2,500 0.94 38.3 7.0 32.8 0.99Teniente Slag Cleaning 5,164 1.23 45.0 9.5 28.2 1.57Settling Furnace 560 3.05 45.3 26.2 25.1 0.65Electric Furnace 815 0.82 40.2 4.8 29.5 0.33Slag FlotationSlag Flotation Feed 2,860 3.55Slag Tailings 2,516 0.85Slag Concentrate 344 30.8

Table IIISlag Chilean smelter industrial slag-cleaning results

*Yearly average data.


technology is based on preheating and reduction of the slagin an electrical furnace AC. In this furnace oxides arereduced by the graphite electrodes and supplementary cokeaddition1213.

The immersion of graphite electrode in the bath producesdirect reduction of magnetite, which generates a gas filmseparating liquid slag from the coal. At the coal/gasinterface Boudouard reaction takes place and at the gas/slaginterface magnetite and cuprous oxide are reduced by thecarbon monoxide. The same reaction occurs at thecarbon/slag interface. The gas generated produces bubblesthat ascend and react with oxides in the slag phase. Thenthe metallic phase is generated and treated in anotherfurnace to obtain Blister Copper. This process is operatingat Paipote and Las Ventanas Smelter Plants, both owned byENAMI (National Mining Companies)14.

Slag flotationThe basic idea is to obtain a copper concentrate by usingflotation techniques. This process was used in the past stillexists as a slag treatment plant in Chuquicamata. Thistechnique was also used widely by small miners because itis a very simple and effective way to recover copper. Theslag flotation has become less important recently due to thedecreasing of copper content in final slags, this was causedby new optimization methods in smelting processes. InChile, Altonorte smelting plant, owned by Noranda, stillcontinue using the flotation process for slags treatment.

International experiencesIn Russia, by processing slags in electrical furnaces it hasbeen possible to recover 98% of copper and 96% ofprecious metals in a metallic phase. Also, a Cyanide-Freeprocess has been developed to separate copper and zinccontained in a concentrate, improving extraction ofnonferrous and precious metals15. Additionally, otherstudies have been reported on treatment of wastescontaining As, Sb, Pb, Bi, Cu, S, etc., by smelting in an arcelectrical furnace to obtain a metallic phase for recoveringprecious metals and copper after further purification16.

The Mintek Company developed a technique forrecovering cobalt, nickel and copper from a wide spectrumof smelting slag. The treatment in this case works parallelto the normal smelting operation, using an arc electricalfurnace17.

In Zambia, great amounts of slag from reverberatoryfurnaces has been dumped containing 13% of cobalt and1.5% of copper. Currently, this slag is being processed in acopper-nickel smelting plant located in Kola using anelectrical furnace. The slag is melted to obtain metallicphase containing cobalt and copper18.

The Ausmelt Company has commercialized severalapplications of the Ausmelt top-submerged lancing process.Cleaning of copper-nickel-cobalt slag has beenimplemented commercially by Rio Tinto, Zimbabwe andAnglo American Corporation. In each plant, a singleAusmelt furnace using a multistage process is applied23.

In U.S., an important number of patents related toprocesses and techniques addressed to recover metalsand/or other materials from slag were developed before1978. In this year a process for reducing molten slag bycarbon injection was patented4. This process enables therecovery of metals from iron-copper slag of coppersmelting furnaces, and iron-nickel slag produced in thesmelting of nickel-bearing ores. In this process, the molten

slag is fed to an electric-arc furnace wherein a molten metalbath is formed. The difference with other processes is givenby a carbon injection unit, including an injector tube, whichis inserted into the furnace.

Some processes using Hydrometallurgical techniqueshave also been developed. At the Universidad de Sevilla,Spain, a bioleaching process named Brisa has beenaddressed to treat non-iron metallic sulphides and refractoryminerals containing gold and silver. It is a non-expensivebacterial process for pretreatment of auriferous pyrites,followed of cyanidation to recover precious metals. Further,liquor is treated by solvent extraction (SX) andelectrowining (EW), to obtain pure metal. Two objectiveshave been considered as priorities in this case: to recovermetal (Cu) and also to obtain a by-product (fayalite) usablefor other industrial applications, such as construction19.

Additionally, studies on the recovery of copper, cobalt,nickel and zinc contained in slag using hydrometallurgicaltreatment, were reported in Holland. This process includesa roasting pretreatment and a subsequent leaching withsulphuric acid20.

Due to American environmental regulations, importantefforts have been made on dissolution of metals containedin wastes prior to its disposal. Thus, studies on recoveringnonferrous metals from smelting slag and dusts by means ofsolvent extraction have been conducted21.

In Turkey, a process for treatment of ancient coppersmelting slag has been proposed. In this process, copperand cobalt are recovered in metallic form and/or ascompounds, whereas iron is recovered as magnetic oxide orpigment, and abrasive material is produced using finalreduced slag. The process stages include carbothermalreduction in a DC arc furnace, granulation, leaching,chemical precipitation, selective sulphidizing roasting andproduct preparations. The results of this work show that theinfluence of granulation on leaching process is veryimportant24. The copper concentration in Kre copper slagwas 0.82%.

In Japan, researchers aim to reuse some wastes such asmunicipal ones, slag and sludge, in order to recovernonferrous metals such as cobalt and copper, have beenalso conducted22.

Expected results and discussionThe project presented to the Chilean National Scientific andTechnological Commission, includes three kinds of studies:Gravimetric and/or magnetic concentration,Hydrometallurgical and Pyrometallurgical treatment. Inorder to carry out these experiments, previous steps ofcomminution and classification is considered. Thisapproach is presented in the flowsheet shown in Figure 1.

Gravimetric and/or magnetic concentrationSince, essentially, iron oxides and silica compose the slag, agood response to gravimetric and magnetic treatment isexpected. As first approach, if comminution has beenoptimal, a separation between higher and lower densitycompounds producing two concentrates is considered. Thatmeans precious metals, copper and part of iron oxides inone side, the rest of iron oxides, silica and others lightcompounds on the other.

The influence of particle size on liberation of componentsis studied, and an important aspect of this research is theenergy consumption during comminution. Thus, in order tominimize this parameter, the influence of granulation in


water jet is the evaluated. Several kinds of unit processesfor gravimetric separation are used. Finally, heavy and lightfractions of solids are obtained. The light fractioncontaining most part of silica could be recycling to thecopper smelting as flux, and the heavy fraction is treated ina magnetic concentrator obtaining two fractions: magneticiron oxide for iron pellet production and non magneticfraction for leaching process, as shown in Figure 1. Theobjective of this part of the research is to obtain three well-defined byproducts in order to make more efficientprogress.

Hydrometallurgical treatment Hydrometallurgical routes depend on the kinds ofcompounds wanted to obtain. Thus, cuprous sulphide,cuprous oxide and metallic copper are the most likelycomponents to be obtained in the case of copper. Thesecompounds require oxidant conditions and usually hightemperature in order to get copper in solution2526.Therefore, leaching tests are programmed using differentoxidant and leaching agents in agitated system. Given thetechnical feasibility, the chance of success of one of thesealternatives depends on issues such as the amount of copperand metals contents in the slag7.

Another alternative for simplifying the treatment is tomodify the compounds through an oxidative roasting stepobtaining an oxidized calcine. In this case, the coppercompounds could be transformed to cupric oxide or cupric

sulphate, that are easily dissolved in diluted acid solution atroom temperature. However, formation of cupric ferritemust be avoided during roasting.

For slag containing important quantities of molybdenumwith appreciable solubility in sulphuric acid solution, it canbe leached with cupric oxide in the same stage. Afterleaching, solvent extraction and ion exchange to separatethe dissolved metals, is evaluated.

The iron compounds obtained are hematite andmagnetite, which are insoluble during leaching the step andthey pass to the solid residue. This residue can beconcentrated for iron recovery or can be considered forother commercial use. The diagram for these twoapproaches is shown in Figure 2.

Precious metals contained in slag are usually inconcentrations of 5 or less ppm for silver and less than oneppm for gold, which requires being concentrated prior tothe hydrometallurgical treatment.

Pyrometallurgical treatmentFor Pyrometallurgical treatment, three possibilities havebeen considered: roasting of slag, high temperatureoxidation of fayalite and direct reduction of iron oxides.

Roasting has been considered in order to obtain a productable to be leached to dissolve copper and precious metals.Based on thermodynamics considerations for theequilibrium of different compounds present in slag, thepossibility of obtaining soluble copper compounds and

Figure 1. Flow sheet of the proposed slag treatment three ways approach


insoluble iron oxide is well known as presented in theKellogg diagram shown in Figure 3, at 600C27. As couldbe expected at this temperature, copper sulfate and hematitecould be formed. Then, avoiding formation of copper oxide,copper ferrite would be minimized.

For fayalite oxidation, additional to high temperatures,oxygen potential of about 10-6 atm is required to ensure thereaction

Since, at high temperatures both magnetite and silicamelt, it is not certain these products would be solid or atleast very viscous during the process. Additionally, risk ofcopper ferrite formation exists if some copper oxide ispresent while magnetite is formed.

The third consideration is direct reduction of slag toreduce iron oxides to metallic iron, and then to obtain iron-copper alloy. In fact, this possibility exists today in coppersmelter plants during slag cleaning processes which,actually, is addressed to reduce magnetite to less oxidizedstates of iron. The limitation of this process in the smelterplant is given by the final metallic phase to be obtained,which must be recycled to the process, and this phase mustbe clean of iron not to contaminate copper production.However, reduction could be forced to iron production if itis done in a separate vessel, after the copper production iscompleted.

In Figure 3, Chaudron diagram for the system Cu-Fe isshown28. From this representation it is possible to make aprediction for required oxygen potential during slagreduction and to determine when metallic iron could appearin the melt system. As can be observed in this diagram, it ispossible to reduce copper oxide at very low CO pressures inthe gas phase. However, as copper oxide activity decreases,possibilities for reduction also decreases.

If we consider a FeO activity in the slag, close to 0.6,which corresponds more or less to a saturated fayalite slag,it is necessary to have a copper oxide activity of 1.4 x 10-4to ensure the same oxygen potential value both for liquidmetallic iron and copper. After which, a liquid iron alloy,containing dissolved copper will appear28.

Final remarks Copper slags have important amount of components

susceptible to be concentrated using differentmetallurgical techniques and methods, such asmagnetic or gravimetric. Once components areseparated, hydrometallurgical and pyrometallurgicalprocesses could be employed to obtain final products.

Main components of non ferrous slags are copper, ironoxides, silica and sometimes precious metals andmolybdenum, as has been detected in Chilean slags.

Slags, as other important wastes today, occurring incopper industry, must be considered as a new mineralresource, which conceptually agree, with thephilosophy of a clean production.

Chile has a particular situation because of the largeamount of slags produced, almost 4.0 millions oftons/year, and with and historically accumulation ofaround 50 millions tons

Copper smelters have a great problem today because ofthe final destination of slags. Smelter plants mustconsider additional cost of transporting this material farfrom sites of generation. Thus, the utilization of slagsin other productive processes is not only good business,but also gives a environmental solution to the coppermining industry.

There are several alternatives of slag processingproposed in the present project. However, the bestoption will be choose after a technical-economicevaluation.

AcknowledgementsAuthors acknowledges CONICYT (Comision Nacional deInvestigacin Cientfica y Tecnolgica, in Chile), forfinancial support given by FONDEF Project No. D02I1159.Also Chilean smelter plants as well as governmentinstitutions participating in this project are acknowledged.

References1a. Waste treatment and environmental impact in the

mining industry (Sanchez, M., Vergara, F., Castro, S.

3 2 2 32 2 3 4 2FeO SiO O Fe O SiO( ) + = +

Figure 2. Flow sheet of hydrometallurgical treatments of copper slag


Eds.) Proceedings of the V International Conferenceon Clean Technologies for the Mining Industry.Universidad de Concepcin, Chile, May 913, 2000.

1b. Environmental improvements in mineral processingand extractive metallurgy (Sanchez, M., Vergara, F.,Castro, S. Eds.) Proceedings of the V InternationalConference on Clean Technologies for the MiningIndustry. Universidad de Concepcin, Chile, May913, 2000.

2. STRUTHERS, S. Recycling and Total ProjectDevelopmentthe key to sustainable mining, articletaken from the paper Total Project DevelopmentAnew approach to mining, presented at Securing theFuture International Conference on Mining and theEnvironment, in Sweden, June 2001.

3. GORAI, B. and JANA, R.K. PremchandCharacteristics and utilisation of copper slagareview Resources, Conservation and Recycling 002003 (article in press). pp. 115

4. DALTON, P. and WILLARD, H. Process forreducing molten furnace slags by carbon injectionU.S. Patent No. 4,110,107 (August, 1978).

5. TARMO, M. Method for utilizing slag from metalproduction U.S. Patent No. 4,818,289 (April, 1989).

6. DEMETRIO, S., AHUMADA, J., DURAN, M.A.,MAST, E., ROJAS, U., SANHUEZA, J., REYES, P.,and MORALES, E. Slag cleaning: the Chileancopper smelter experience, JOM (August 2000), pp. 2025.

7. Comisin Nacional de Investigacin Cientfica yTecnolgica, CONICYT, FONDEF Project No.D02I1159 Obtencin de subproductos con valorcomercial a partir de escorias piro metalrgicasprovenientes de fundiciones de concentrados de cobrede la gran minera en Chile, 2002.

8. STRUTHERS, S., BRUMLEY, J., and TAYLOR, G.(a) Recycling of base metal mine tailings. Tailingsand Mine Waste 97. Proceedings of the Fourth

Figure 3. Kellogg diagrams for Cu-S-O and Fe-S-O systems at 600C27

Figure 4. Chaudron diagram for the system Cu-Fe

20

15

10

5

0

-5

-10

-15

-20-12 -10 -8 -6 -4 -2 0Constant value: p[O2(g)]T / C = 600.00

p[SO2(g)]

Fe2O3Fe3O4

Fe2(SO4)3FeS2

FeSO4

Predominance Diagram for Fe-O-S System20

15

10

5

0

-5

-10

-15

-20-12 -10 -8 -6 -4 -2 0Constant value: p[O2(g)]T / C = 600.00

p[SO2(g)]

Cu2SO4

Cu Cu2O CuO

CuO*CuSO4

CuSO4CuS

Cu2S

Predominance Diagram for Cu-O-S System


International Conference on Tailings and Mine Waste97. Fort Collins, Colorado, USA, 1317 January,1997.

9. STRUTHERS, S., BRUMLEY, J., and TAYLOR, G.(b) An integrated system for recycling base metalmine tailings. Vision 2000 An EnvironmentalCommitment. 14th Annual Meeting of the AmericanSociety for Surface mining and reclamation, Austin,Texas, May, 1997. pp. 1116.

10. Stony Mining Society Quiln, 2001. 11. IMRIS, I., REBOLLEDO, S., SNCHEZ, M.,

CASTRO, S., ACHURRA, G., and HERNANDEZ, F.The copper losses in the slags from El Tenienteprocess. Acta Metallugica Slovaca, 4, 3/1998, pp. 6978

12. IMRIS, I., REBOLLEDO, S., SNCHEZ, M.,CASTRO, S., ACHURRA, G., and HERNANDEZ,F. The copper losses in the slags from the ElTeniente process, Canadian Metallurgical Quarterly,vol. 39, no. 3, July 2000, pp. 281289.

13. REBOLLEDO, S., SNCHEZ, M., PUCHI, F., andIMRIS, I. Physicochemical characterisation andindustrial evaluation of converter slags, Proceedingsof the Sixth International Conference on MoltenSlags, Fluxes and Salts, Stockholm, Sweden &Helsinki, Finland, 1217 June, 2000, CD containingproceedings, ISBN 91-7170-606-2

14. RIVEROS G. and WARCZOK A. Rol de variosfenmenos fsico-qumicos en limpieza de escoria,51a Convencin Anual del Instituto de Ingenieros deMinas de Chile, 2730 de Septiembre del 2000,Santiago, Chile.

15. KUBASOV, V.L. and TARASOV, A.V. Solution ofecological problems: one of the main directions inactivity of Gintsvetment, (Gintsvetment (Moscow)).Tsvetn. Met., Aug. 1997, pp. 813.

16. PARETSKII, V.M., NUS, G.S., PANFILOV, S.A.,and KALNIN, E.I. Processing of technogeneous rawmaterials in direct current furnaces. TsvetnayaMetallurgia (Russia), vol. 4, Apr. 1996. pp. 4750.

17. JONES, R.T. (Mintek), Recovery of cobalt, nickeland cooper from slags using DC-arc furnacetechnology, Cobalt News, Apr. 1998, pp. 26.

18. Reznik (Gintsvetmet Institute (Moscow)), Cobaltextraction from copper-cobalt slags, Cobalt News,Oct. 1997,3,pp. 1314.

19. MAZUELOS, A., CARRANZA, F., PALENCIA, I.,and ROMERO, R. High Efficiency reactor for thebiooxidation of ferrous iron. Hydrometallurgy.vol. 58. 2000. pp. 269275.

20. ALTUNDOGAN, H.S. and TUMEN F.Metalrecovey from copper converter slag by roasting withferric sulphate. Hydrometallurgy (Netherlands), vol.44, no. 12, Jan. 1996. pp. 261267.

21. MUKHERJEE, T.K. and GRUPTA C.K. Flowsheetsdevelopment for recovery of non-ferrous metal valuesfrom secondary resources by solvent extractions.Minerals, Metals and Materials Society/AIME (USA),1996. pp. 249262.

22. MAEDA, M., NAKAMURA, T. and NISHIMURA,Y. Copper recycling project in Japan: super smelterand super dust concept. Minerals, Metals andMaterials Society/AIME (USA). 1995. pp. 215221.

23. Hughes, S. Applying Ausmelt Technology to recoverCu, Ni, and Co from slags, JOM (August 2000), pp. 3033.

24. DERIN, B., CINAR, F., YSEL, O., ACMA, E., andADDEMIR, O. A Process designed for the ancientcopper smelting slags, Yasawa InternationalSymposium. Metallurgical and materials processing:Principles and technologies 2003. pp. 471482.

25. BANZA A.N., GOCK E., and KONGOLO K. Basemetals recovery from copper smelter slag by oxidisingleaching and solvent extraction. Hydrometallurgy,vol. 67, no. 13, pp. 1-7, Dec. 2002, pp. 6369.

26. ARSLAN, C. and ARSLAN, F. Recovery of copper,cobalt, and zinc from copper smelter and converterslags. Hydrometallurgy (Netherlands), vol. 67, no. 13, Dec. 2002, pp. 17.

27. Outokumpu HSC Chemistry for Windows, Version4.0.

28. PARRA, R. Etude experimentale de la fusionreductrice du Cu2O dans le systeme Cu2O FeOx -SiO2,Dr. Eng. Thesis, National Polytechnical Instituteof Grenoble, France, 1998.

management of copper pyrometallurgical slags

Documents