Annukka Aaltonen - Academia.edu (original) (raw)
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Papers by Annukka Aaltonen
Journal of Sol-Gel Science and Technology, 2007
Magnetic powders based on metallic iron crystallites encapsulated in submicron-sized spherical si... more Magnetic powders based on metallic iron crystallites encapsulated in submicron-sized spherical silica particles have been obtained and investigated. The metallic iron clusters have been produced by the exploding wire method. The silica shells have been prepared via the modified sol-gel Stöber method and the metallic particles have been entrapped by occlusion during the silica powder formation. The entrapped iron particles are partially oxidized
This Master's thesis studies the consequences of integrating a hydrometallurgical process wit... more This Master's thesis studies the consequences of integrating a hydrometallurgical process with the concentration of an ore. The study covers the whole chain from grinding to sales of metal semi-products. Different concentration process alternatives and their effects on the economics of the chain are examined. The literature survey focuses on different leaching processes developed for sulphide copper, nickel and zinc concentrates. The prospects, boundary conditions and economics of processes that can be utilised in mine-site refining are discussed. In the experimental part, economic calculations are made on the basis of process simulations. The simulations were made using Outotec's HSC Chemistry® Sim 6.1 software on two copper ore cases. The economics of integrated processes with different copper grades of the concentrate are compared and a sensitivity analysis is performed on the main design criteria. According to the calculations, in the case of Cu-Zn ore the whole proc...
Minerals
Blending of different ore types in the concentrator feed contributes significantly to maintaining... more Blending of different ore types in the concentrator feed contributes significantly to maintaining a high recovery of valuable minerals with required grades in the concentrate. It is feasible to develop an ore-blending scheme over the life of a mine already in the design phase of the plant. In addition to ore characteristics, water quality is known to impact mineral recovery. A blending plan could also be developed for the different water streams of a future concentrator. This paper describes a novel modeling and simulation approach to predict metallurgical response combining ore types and water quality. The model is based on kinetic laboratory flotation test data, and it was tested on a case study. As a result, rougher flotation grade-recovery curves dependent on ore types and water quality are presented over the predicted life of the mine. The simulation results can be exploited in project design to maximize the recovery of valuable minerals and to ensure environmentally sound and ...
Minerals
The pressure for saving water by closing the water loops in mineral processing is increasing cont... more The pressure for saving water by closing the water loops in mineral processing is increasing continuously. The drivers for higher recirculating rates include water scarcity in dry areas, environmental legislation that is becoming stricter in most countries, limitations set for wet tailings management and the increased demands for social licenses to operate. At the same time, to make mineral processing sustainable, the recovery of valuable minerals should be maximized. This leads for a need to close the process water circulation. To see the effect of closed water circulation on metallurgical performance, flotation tests were carried out with nickel concentrate thickener overflow water before and after the process of water purification by dissolved air flotation (DAF). Both total nickel recovery and concentrate grade in laboratory scale flotation tests to the Ni rougher-scavenger concentrate increased after DAF treatment. Chemical and mineralogical characterizations revealed that afte...
Journal of Sol-Gel Science and Technology, 2007
Magnetic powders based on metallic iron crystallites encapsulated in submicron-sized spherical si... more Magnetic powders based on metallic iron crystallites encapsulated in submicron-sized spherical silica particles have been obtained and investigated. The metallic iron clusters have been produced by the exploding wire method. The silica shells have been prepared via the modified sol-gel Stöber method and the metallic particles have been entrapped by occlusion during the silica powder formation. The entrapped iron particles are partially oxidized
This Master's thesis studies the consequences of integrating a hydrometallurgical process wit... more This Master's thesis studies the consequences of integrating a hydrometallurgical process with the concentration of an ore. The study covers the whole chain from grinding to sales of metal semi-products. Different concentration process alternatives and their effects on the economics of the chain are examined. The literature survey focuses on different leaching processes developed for sulphide copper, nickel and zinc concentrates. The prospects, boundary conditions and economics of processes that can be utilised in mine-site refining are discussed. In the experimental part, economic calculations are made on the basis of process simulations. The simulations were made using Outotec's HSC Chemistry® Sim 6.1 software on two copper ore cases. The economics of integrated processes with different copper grades of the concentrate are compared and a sensitivity analysis is performed on the main design criteria. According to the calculations, in the case of Cu-Zn ore the whole proc...
Minerals
Blending of different ore types in the concentrator feed contributes significantly to maintaining... more Blending of different ore types in the concentrator feed contributes significantly to maintaining a high recovery of valuable minerals with required grades in the concentrate. It is feasible to develop an ore-blending scheme over the life of a mine already in the design phase of the plant. In addition to ore characteristics, water quality is known to impact mineral recovery. A blending plan could also be developed for the different water streams of a future concentrator. This paper describes a novel modeling and simulation approach to predict metallurgical response combining ore types and water quality. The model is based on kinetic laboratory flotation test data, and it was tested on a case study. As a result, rougher flotation grade-recovery curves dependent on ore types and water quality are presented over the predicted life of the mine. The simulation results can be exploited in project design to maximize the recovery of valuable minerals and to ensure environmentally sound and ...
Minerals
The pressure for saving water by closing the water loops in mineral processing is increasing cont... more The pressure for saving water by closing the water loops in mineral processing is increasing continuously. The drivers for higher recirculating rates include water scarcity in dry areas, environmental legislation that is becoming stricter in most countries, limitations set for wet tailings management and the increased demands for social licenses to operate. At the same time, to make mineral processing sustainable, the recovery of valuable minerals should be maximized. This leads for a need to close the process water circulation. To see the effect of closed water circulation on metallurgical performance, flotation tests were carried out with nickel concentrate thickener overflow water before and after the process of water purification by dissolved air flotation (DAF). Both total nickel recovery and concentrate grade in laboratory scale flotation tests to the Ni rougher-scavenger concentrate increased after DAF treatment. Chemical and mineralogical characterizations revealed that afte...