| 1. |
- Ding, Limei, et al.
(författare)
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Application of fuzzy control to a flotation process
- 1999
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Ingår i: Elsevier IFAC Publications / IFAC Proceedings series. - Kildington : Elsevier. - 1474-6670. ; 32:2, s. 6998-7003, s. 391-396
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Tidskriftsartikel (refereegranskat)abstract
- The application of fuzzy logic in the control of flotation is studied in this paper. A general description of apatite flotation process is given and a dynamic model is developed. A fuzzy logic controller is proposed for a nonlinear isolated continuous flotation process. The knowledge base of the controller is constructed on the basis of the semi-batch results from the apatite flotation experiments and available knowledge sources. The design of the controller does not need an exact process model. The simulation result shows that the fuzzy logic controller can reduce collector dosage consumption of the apatite flotation process while maintaining the phosphorous content in magnetite concentrate within an acceptable limits less than 0.025% P. Stability of the fuzzy control system is discussed
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| 2. |
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| 3. |
- Larsson, Mikael, et al.
(författare)
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Improved energy and material efficiency using new tools for global optimisation of residue material flows
- 2006
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Ingår i: International Journal of Green Energy. - : Informa UK Limited. - 1543-5075 .- 1543-5083. ; 3:2, s. 127-137
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Tidskriftsartikel (refereegranskat)abstract
- Residue materials generated in the metallurgical industry have gained an increasing importance, both from the points of view of energy and material supply. A joint process integration model for the integrated steel plant system is developed and used in this paper. It takes into account both residue materials and energy recirculation for the system. The potential for increased recirculation and the effect on the system from an environmental point of view is presented, and implementations and practical experiences are discussed. The model developed can serve as a benchmark for different steelmaking operations and constitute a basis for the continuous work involved in material, energy, environment or economic analyses for the steel production system.
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| 4. |
- Su, Fenwei
(författare)
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Dephosphorization of magnetite fines
- 2002
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Ingår i: Magnetic and Electrical Separation. - 1055-6915 .- 1029-0303. ; 11:1-2, s. 108-
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The dephosphorization of magnetite fines by flotation and simultaneously reducing fatty acid coating on magnetite surface are currently important challenges facing the mineral industry in Sweden. These problems can be resolved to a greater extent by optimising apatite flotation process, which depends largely on the proper control of chemical variables. The primary objective of the research work presented in this thesis is to investigate the influence of chemical and operational variables on the apatite flotation kinetics and to establish a suitable model using traditional method and fuzzy logic.
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| 5. |
- Su, Fenwei, et al.
(författare)
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Dephosphorization of magnetite fines : Part 2: Influence of chemical variables on flotation kinetics
- 1998
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Ingår i: Mineral Processing and Extractive Metallurgy. - 0371-9553 .- 1743-2855. ; 107, s. C103-C110
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Tidskriftsartikel (refereegranskat)abstract
- The influence of chemical and operational variables on the kinetics of apatite flotation from magnetite was investigated through batch flotation tests in a specially designed, temperature-controlled cell. The significance for the apatite flotation kinetics of four variables - collector, dispersant, pulp pH and temperature - and their interactions was examined through experiments conducted according to a full factorial design. The kinetic parameters of a first-order model with fast and slow floating distribution were utilized in judging the influence of reagent dosage on flotation performance. Statistical tests on phosphorus kinetic data show that collector and dispersant doses have a significant effect on phosphorus recovery. However, pulp temperature is the dominant factor for flotation rate. Increase in pulp temperature increases the flotation rate. The recovery of phosphorus increases with increasing collector dose at a given dispersant dose; however, the flotation rate decreases at doses of collector exceeding 65 g/t when the dispersant is at a higher level. The effect of dispersant dosage on flotation rate is observed to be nonlinear and quite complex owing to the interaction effects between collector and dispersant doses. The maximum recovery of phosphorus with minor loss of magnetite concentrate was obtained at pH 9, with either 30 or 65 g/t collector. The optimum flotation conditions were 65 g/t collector, 350 g/t dispersant, pH 8-9 and a pulp temperature of about 20 deg C
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| 6. |
- Su, Fenwei
(författare)
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Dephosphorization of magnetite fines : surface reactions, flotation kinetics and fuzzy logic application
- 1998
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The primary objective of the research work presented in this thesis is to investigate the influence of chemical and operational variables on the apatite flotation kinetics and to establish a suitable model using traditional method and fuzzy logic. The thesis consists of three parts, i.e., surface reactions, flotation kinetics and fuzzy logic application. In the thesis, the kinetic parameters of a modified first-order model with fast and slow-floating components were utilized in judging the influence of reagent dosages on flotation performance. The optimum flotation conditions were presented and a fuzzy model of general semi-batch flotation is used to predict the influence of collector and dispersant dosages on flotation responses. The simulation result shows that a developed fuzzy logic controller can reduce collector dosage consumption of the apatite flotation process while maintaining the P-MC within an acceptable limits (<0.025%P).
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| 7. |
- Su, Fenwei, et al.
(författare)
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Dephosphorization of magnetite fines - Part 1: Evaluation of flotation kinetic models
- 1998
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Ingår i: Mineral Processing and Extractive Metallurgy. - 0371-9553 .- 1743-2855. ; 107:SEPT/DEC, s. C95-C102
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Forskningsöversikt (refereegranskat)abstract
- Dephosphorization of magnetite fines by flotation in such a way as to minimize the fatty acid coating left on the magnetite surfaces is the principal technical challenge facing the mineral processing division of LKAB, Sweden. Modelling of flotation kinetics enables the influence of chemical and operational variables on apatite flotation from magnetite fines to be predicted. Five typical first-order flotation kinetic models are evaluated by statistical techniques, after an estimation of model parameters by a nonlinear least-squares fitting program, with use of the authors' own results and results taken from the literature. Evaluation of the models is based on two aspects: goodness of fit to the experimental results and suitability to describe the flotation behaviour. The first-order models with a rectangular distribution of floatabilities and with fast and slow floating components (F-S model) gave an excellent fit to the experimental results of apatite flotation when compared with the other models, the latter being superior not only in the goodness of fit to apatite flotation and other mineral flotation results but also in its description of flotation behaviour. The kinetic parameters (percentage recoveries and rate constants of fast and slow floating particles) in the F-S model have a physical significance and can thus be used for qualitative as well as quantitative interpretation of flotation performance. The influence of collector dose can be effectively included in the F-S model by making realistic simplifications and relating the collector dose to the fraction of slow floating particles. The ratio of fast and slow rate constants can be used to describe the selectivity of apatite flotation from magnetite.
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| 8. |
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| 9. |
- Su, Fenwei, et al.
(författare)
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Industrial tests on charging cold bonded pellets as part of burden materials in the BOF converter
- 2005
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Ingår i: Global Symposium on Recycling, Waste Treatment and Clean Technology (REWAS'04). - : Minerals, Metals & Materials Society. - 8495520052 ; , s. 1943-1952
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Konferensbidrag (refereegranskat)abstract
- Industrial tests on recycling of iron-bearing sludges through BOF converter in the form of cold bonded pellets were carried out at the S SAB Tunnplat. The total amount of about 400 tons of cold bond pellets was produced in a pilot scale pelletizing plant on the basis of the results of experimental studies concerning cold strength and reduction behaviour. The charging weight of cold bonded pellets in the BOF converter with 114 tons varied from 0,5 to 2,5 tons. The effect of charging cold bonded pellets on the amount of sludge and the composition of slag generated in the BOF converters was studied. The slopping problem occurred in the industrial tests is discussed. According to the results of industrial tests, in general the converter process was not subject to any adverse disturbances due to the addition of cold bonded pellets. Dust, sludge, recycling, cold bonded pellets, pilot scale tests and industrial tests.
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| 10. |
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| 11. |
- Su, Fenwei, et al.
(författare)
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Recycling of sludge and dust to the BOF converter cold bonded pelletizing
- 2004
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Ingår i: ISIJ International. - : Iron and Steel Institute of Japan. - 0915-1559 .- 1347-5460. ; 44:4, s. 770-776
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Tidskriftsartikel (refereegranskat)abstract
- With the aim to increase the recycling of fine sludge and dust disposed normally in landfill, cold bonded pelletizing of the sludge and dust using cement as binder was investigated in laboratory scale as well as in the pilot scale pelletizing plant. The influence of BF flue dust, BOF fine sludge and oily mill scale sludge on the cold strength, capacity and reduction degree of cold bond pellets was studied experimentally on the basis of a statistical procedure. With a coarser representative particle size, oily mill scale sludge has the greatest effect on the cold strength. BF flue dust has a negative effect for increasing both the cold strength and capacity for levels of over 25% of the mixture. The BOF fine sludge has the positive effect on cold strength, while its interaction with BF flue dust has the negative effect on reduction degree. The results of pelletizing tests in pilot scale show that the maximum cold strength (TTH 94%) and capacity (13-15 t/h) of products is obtained at the conditions given by the optimal mixture design and cure time. The industrial tests on charging cold bonded pellets as burden material in the BOF converter were described. The charging weight of cold bonded pellets varied from 0.5 to 2.5 tons. The results of industrial tests indicated that the converter process was not subject to any adverse disturbances due to the addition of 2.5 tons of cold bonded pellets.
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| 12. |
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| 13. |
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| 14. |
- Su, Fenwei, et al.
(författare)
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The influence of temperature on the kinetics of apatite flotation from magnetite fines
- 1998
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Ingår i: International Journal of Mineral Processing. - 0301-7516 .- 1879-3525. ; 54:3, s. 131-145
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Tidskriftsartikel (refereegranskat)abstract
- The influence of pulp temperature on the kinetics of apatite flotation from magnetite fines was studied using Atrac (fatty acid type) as collector and sodium silicate as dispersant at pH 8.5–9.0. The batch flotation tests were conducted in a specially designed temperature controlled flotation cell. A modified first-order model, incorporating two rate terms describing fast and slow-floating components, was applied to evaluate the flotation kinetics. The estimation of the model parameters was made by a non-linear least squares fitter program which is based on the Levenberg–Marquardt algorithm. Results indicate that increasing temperature from 10°C to 40°C decreases the phosphorous content in magnetite concentrate but with a simultaneous loss of magnetite recovery. At temperatures below 30°C, an increase in pulp temperature results increasing flotation rate of fast-floating particles and has a marginal effect on slow-floating particles. Above 30°C, the flotation rate of fast-floating particles decreases with increasing pulp temperature. Sodium silicate has a positive effect for increasing the phosphorous recovery and decreasing the phosphorous content in the magnetite concentrate at 20°C for all the levels of collector dosages. In the absence of sodium silicate, collector is active for both apatite and magnetite flotation. The higher selectivity between apatite and magnetite with an acceptable content of phosphorous in the magnetite concentrate is obtained at a moderate dosage of about 400 g/t sodium silicate. The optimum flotation conditions are: 50 g/t collector dosage, 350–400 g/t dispersant dosage, pH 8.5–9 and pulp temperature 25–30°C.
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| 15. |
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