Classifications

• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
  • C22B1/00—Preliminary treatment of ores or scrap
  • C22B1/02—Roasting processes
  • C22B1/10—Roasting processes in fluidised form
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
  • B01J8/0015—Feeding of the particles in the reactor; Evacuation of the particles out of the reactor
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
  • B01J8/005—Separating solid material from the gas/liquid stream
  • B01J8/0055—Separating solid material from the gas/liquid stream using cyclones
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
  • B01J8/18—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles
  • B01J8/1818—Feeding of the fluidising gas
  • B01J8/1827—Feeding of the fluidising gas the fluidising gas being a reactant
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
  • B01J8/18—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles
  • B01J8/1836—Heating and cooling the reactor
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
  • B01J8/18—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles
  • B01J8/24—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles according to "fluidised-bed" technique
  • B01J8/44—Fluidisation grids
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F27—FURNACES; KILNS; OVENS; RETORTS
  • F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
  • F27B15/00—Fluidised-bed furnaces; Other furnaces using or treating finely-divided materials in dispersion
  • F27B15/02—Details, accessories, or equipment peculiar to furnaces of these types
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F27—FURNACES; KILNS; OVENS; RETORTS
  • F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
  • F27B15/00—Fluidised-bed furnaces; Other furnaces using or treating finely-divided materials in dispersion
  • F27B15/02—Details, accessories, or equipment peculiar to furnaces of these types
  • F27B15/08—Arrangements of devices for charging
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2208/00—Processes carried out in the presence of solid particles; Reactors therefor
  • B01J2208/00008—Controlling the process
  • B01J2208/00017—Controlling the temperature
  • B01J2208/00106—Controlling the temperature by indirect heat exchange
  • B01J2208/00115—Controlling the temperature by indirect heat exchange with heat exchange elements inside the bed of solid particles
  • B01J2208/0015—Plates; Cylinders
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2208/00—Processes carried out in the presence of solid particles; Reactors therefor
  • B01J2208/00008—Controlling the process
  • B01J2208/00654—Controlling the process by measures relating to the particulate material
  • B01J2208/00681—Agglomeration
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2208/00—Processes carried out in the presence of solid particles; Reactors therefor
  • B01J2208/00743—Feeding or discharging of solids
  • B01J2208/00752—Feeding
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2208/00—Processes carried out in the presence of solid particles; Reactors therefor
  • B01J2208/00743—Feeding or discharging of solids
  • B01J2208/00769—Details of feeding or discharging
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2208/00—Processes carried out in the presence of solid particles; Reactors therefor
  • B01J2208/00796—Details of the reactor or of the particulate material
  • B01J2208/00991—Disengagement zone in fluidised-bed reactors

Definitions

• the invention refers to a process for the roasting of ore particles containing carbon and/or sulfur, whereby the particles are fed into the reactor for roasting, wherein oxygen is introduced, wherein the particles are fluidized in fluidized bed at a temperature of 500 to 1000 °C for at least 10 sec and wherein the roasting particles are withdrawn from the reactor. Furthermore, the present invention also relates to a plant suitable for carrying out the process.
• Roasting is a step of the processing of certain ores. More specifically, roasting is a metallurgical process involving gas-solid reactions at elevated temperatures with the goal of separating of the metal compounds. Often before roasting, the ore has already been treated in beneficiation plants, like for example by froth floatation. But also grinded whole ore can be treated.
• the ores concentrate is treated with very hot air.
• the process is generally applied to minerals containing sulfur and/or carbon.
• the sulfide and/or carbonates and/or org. carbon is/are converted to an oxide and sulfur is released as sulfur dioxide and org. carbon to cabon dixide or cabon monoxide.
• CU2S (chalcocite) and ZnS (sphalerite) balanced equation for the roasting are:
• Organic carbon is converted according to the following equation: Corg + O 2 ⁇ CO 2
• a typical roasting process is described in document DE 976 145 A1 , wherein a typical roaster is described. Therein, ore particles are fed into a fluidized bed reactor, which is built as such, that its cross-section is enlarged from the bottom up whereby particles of each diameter can be fluidized.
• Document DE 3 300 609 deals with a process for particle roasting, wherein an excess of an oxidation gas is used in a fluidized bed reactor.
• Document DE 907 417 describes a process for the reduction of Fe2O3 to Fe3O 4 by using carbon as an oxidizing agent.
• document DE 101 0 646 teaches with the reduction of Fe2O3, whereby three fluidized bed systems are used, which are built on top of each other.
• Document CH 538 655 describes a fluidized bed to convert manganese or magnesium sulfate in the cross bonding oxide. As it is typical for roasting processes, the educts are fed into the reactor from above.
• the ore concentrate is fed with a water content of 5 to 12 wt.-%.
• the concentrate of the moisture of 5 to 12 wt.-% is normally carried into the roaster with a slinger belt over a bed in the roaster. Feeding dry concentrate with high energy content, would save the additional necessary energy cost to evaporate the contained water. However, it is not possible to feed the dry material with a slinger belt. Feeding material over the belt would lead to the effect that a high amount of material would fly into the free board over the fluidized bed.
• the solids would react, being overheated and forming agglomerates with themselves on the top of the roaster. As a result, not only clumps would be built up, but also the top of the roaster with bricks etc. would be overheated.
• the particles are fed into the roasting reactor. Further, an oxygen containing gas is introduced, which is preferably used as fluidizing gas.
• the particles are fluidized inside of the reactor in a fluidized bed at a temperature of 500 to 1000 °C for at least 10 sec.
• An average retention time in a normal fluidized bed reactor is in the range of 20 to 50 minutes.
• the particles have a surface water content of maximal 2 wt.-%, preferred maximal 1 wt.-% and are injected pneumatically into the fluidized bed. Therefore, the material can react in the bed as re- quested, since next to the outlet of the feeding line, the particle concentration is diluted due to the pneumatic gas. As a result, the energy consumption is reduced since no water has to be evaporated.
• the ratio between pneumatic gas and particle weight would be in maximum 10 kg solids per kg of pneumatic gas.
• the org. carbon content is between 0 and 8 wt.-% and/or the metal sulfide - sulfur content is between 3 and 55 wt.-%. In this range, the yield of the reaction is as high as possible.
• the average diameter of the particle is between 0,001 and 10 mm, preferred 0,001 and 2 mm.
• the particles can be fluidized in typical fluidized bed reactors.
• the design of the fluidized bed is a bubbling fluid bed. Bubbling system takes place when the inlet gas velocity of the fluidized gas is slightly greater than the minimum fluidizing velocity. This contributes to a small expansion in the bed. Small bubbles tend to become adapted in the dense phase where it is injected into a stationary, therefore non- bubbling bed. Subsequently, when the gas flow in the dense phase increases, large bubbles tend to rise. If the bubbles are larger than the critical size, the bed will start to expand in an amount which is the same as a volume of the injected bubble.
• roasting reactions are exothermic reactions. Therefore, a fluidized bed has to be cooled.
• the fluidized bed is cooled via at least one cooling device, like cooling coils or cooling plates which sticks into the bed.
• the particles are injected inside of one cooling device, like between two cooling plates or inside of a cooling coil. It is also possible to inject the particle with a distance of 50 cm or less, preferably 25 cm or less, most preferably 15 cm or less to the cooling device. This offers the possibility to inject the particles in a region, where the temperature is locally lower than the average temperature of the fluidized bed. Therefore, the risk of agglomeration can be lowered further.
• an inert gas like nitrogen as the gas for the pneumatic injection. Thereby, clumping can be reduced since not only the local particle concentration but also to the local oxygen concentration is lowered.
• the particles are introduced via at least one nozzle, whereby the average ve- locity of the particles in the nozzle(s) is between 10 and 60 m s ⁇ 1 .
• the invention also comprises an apparatus for roasting of ore particles containing org. carbon and/or sulfide-sulfur with the features of claim 8.
• an apparatus comprises a fluidized bed reactor for performing the roasting process.
• the fluidized bed reactor features at least one feeding line to introduce ore particles containing org. carbon and/or sulfide-sulfur, one oxygen line to have oxygen containing gas stream and an outlet line to remove the roasted particles from the reactor.
• the feeding line features a pneumatic delivery system and has at least one opening which is positioned such during operation that the particles are directly fed inside of the fluidized bed.
• At least one cooling device is installed such that during operation it sticks into the fluidized bed of the fluidized bed reactor.
• the cooling device features at least two cooling plates and/or at least one cooling coil.
• the outlet of the feeding line ends between the cooling plates and/or inside of the cooling coil. It is also possible that the outlet is situated with a distance of 50 cm or less, preferably 25 cm or less, most preferably 15 cm or less to the cooling device. Thereby, the local temperature at the feeding position is lowered, which is why the activation energy needed for an agglomeration is not reached.
• the reactor can be configured such that the feeding line features at least four outlets which are evenly distributed in the reactor.
• Fig. 1 shows schematically an apparatus according to the invention
• Fig. 2 shows schematically a cross section of the reactor.
• the apparatus 10 features a feeding line 13 for injecting ore particles into the reactor 1 1 .
• the feeding line 13 includes a pneumatic delivery system 12.
• an outlet line 16 is foreseen.
• Oxidizing gas is introduced via oxygen line 15, whereby the oxidizing gas, preferably air, is also used as fluidizing gas, which is why it is introduced at the bottom of the reactor 1 1 .
• the fluidized gas has to be passed through a perforated base 20.
• a fluidized bed 21 is situated during operation above the perforated base 20.
• the so called freeboard 22 is situated on the top of the reactor 1 1 .
• a line 30 is foreseen to withdraw the roasting gases.
• Line 30 ends in a cyclone 31 , wherein the gas is separated from small particles carried out.
• the gases are passed from cyclone 31 via a line 32 to a, not-shown further gas cleaning while the particles separated in cyclone 31 are passed via a line 33 back into the reactor 1 1 .
• cooling devices 17 in form of line cooling plates are installed such that during operation they are inside of the fluidized bed 21 .
• the feeding line 13 leads into the middle of these cooling devices 17 and injects ore particles via an injection nozzle 14 between the cooling devices 17 designed as cooling plates. Therefore, the local temperature at the injection position is lowered to avoid agglomeration.
• Fig. 2 shows a cross section of the reactor 10. Over feeding line 13, material is transported to the injection nozzles 14. All injection nozzles are positioned between two cooling devices 17 built as plates. Thereby, the injection position features a temperature of at least 3 °C, preferably 5 °C, most preferably more than 10 °C lower than the average reactor temperature to lower the risk of agglomeration.
• the perforated base 20 is not perforated in the regions of the cooling devices 17 and the infection nozzles 14. As a result, no fluidizing gas is introduced in these regions.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• Dispersion Chemistry (AREA)
• General Engineering & Computer Science (AREA)
• Life Sciences & Earth Sciences (AREA)
• Environmental & Geological Engineering (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Geology (AREA)
• Manufacturing & Machinery (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Manufacture And Refinement Of Metals (AREA)
• Crucibles And Fluidized-Bed Furnaces (AREA)

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• 2015
  • 2015-07-03 DE DE102015110772.4A patent/DE102015110772A1/de not_active Withdrawn
• 2016
  • 2016-06-23 WO PCT/EP2016/064589 patent/WO2017005501A1/en active Application Filing
  • 2016-06-23 AU AU2016289602A patent/AU2016289602B2/en not_active Ceased
  • 2016-06-23 PL PL424587A patent/PL233905B1/pl unknown
• 2017
  • 2017-12-26 CL CL2017003360A patent/CL2017003360A1/es unknown

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