Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
  • B03D—FLOTATION; DIFFERENTIAL SEDIMENTATION
  • B03D3/00—Differential sedimentation
  • B03D3/06—Flocculation

Definitions

• the present invention generally relates to a method of producing a concentrate containing very high purity iron oxide with very low alumina and silica from a poor grade iron ore fines. More particularly, the invention relates to a process for producing high purity Fe 2 0 3 for value added applications including blast furnace feed from a poor grade iron ore slime.
• Iron ore production entails generation of fines (10-25%) containing high alumina (6-8%), which is unsuitable for direct use in the blast furnace. Assuming an annual production of 150 tons of iron ore, the iron values to the tune of 15- 25 million tones is lost every year.
• the main drawback for use of iron ore ultra fines is that high level of clay are associated with it. As a consequence, this ultra fines being rejected and getting wasted including causing environmental hazards.
• the particle size of these ultra fines is not suitable to beneficiate it by known beneficiation processes such as (i) gravity or (ii) magnetic separation.
• the known beneficiaation processes separate minerals from the mixture of two oxides. But, iron ore ultra fines are mixtures of different oxides, which have no utility . It is mixed with goethite, silica, alumina, alumina silicate,refractory minerals.
• the selective flocculation process is known to be adapted to separate iron oxide as red mud from bauxite. It is expected that such a process could be considered to beneficiate such ultra fines. Also this process can be deployed to improve the brightness of selectively separated silica. Thus, a selective flocculation of these fines could be a viable option for efficient separation of alumina and silica from the iron bearing minerals.
• Another object of the invention is to propose a process for producing high purity Fe 2 0 3 for value added application and blast furnace feed from a poor grade iron ore slime, which provides a first grade of product containing only very low amount of alumina and silica adaptable for high-valued product or blast furnace feed.
• a further object of the invention is to propose a process for producing high purity Fe20 3 for value added application and blast furnace feed from a poor grade iron ore slime, which provides a second grade of product containing high alumina and silica suitable for making building or refractory material.
• various grades of rejected ultra fines can be separated out into two categories, (i) a concentrate for value-added applications including blast furnace feed by the selective flocculation followed by pelletization process, the concentrate can be further separated into a good concentrate and a high grade concentrate, the later requiring a two- step selective flocculation process; and (ii) a tailing (with rich in alumina and silica) containing mostly as sillimanite and quartz by selective dispersion and selective flocculation process. Both the alumina and silica levels in the ultra fines are in the range of 2.5 to 14wt%.
• the alumina and silica levels in the concentrate can be dropped down to a level of 0.8 whereas both the alumina and silica level in the tailing can be up to 21 wt% with varying level of yield of concentrate.
• the concentrate is most suited as the feed material for iron making through the blast furnace route, whereas the tailing is most suited as the feed material to make building material.
• the tailing material may be potentially suited for other applications like feed material for formulation of nano paint and nano coolant. Added advantage is that this process is environmental and eco friendly with zero waste.
• the invention provides a process for producing a high purity Fe 2 03 for value added application and blast furnace feed from a poor grade iron ore slime .
• the process provides a concentrate containing a very high purity iron with very low alumina and silica from the slime containing high alumina and silica generated in the iron ore mines and the iron ore washing plants.
• all the oxide minerals are dispersed and subsequently flocculated selectively under specific conditions.
• Two products are produced in this process, namely a concentrate, and a tailing.
• the concentrate contains 68.5% Fe with only around 0.8% alumina and 1.0% silica from the slime containing around 54.5% Fe, 7.61 % alumina and 7.42% silica.
• This concentrate is suitable for value added applications like in medical science, paint formulation, removal of hazardous elements from contaminated water and soil, and also as the blast furnace feed.
• the tailing are generated in this process contains 29.8% Fe with 20.5% Al 2 0 3 and 19.68% Si0 2 present mainly as the sillimanite and quartz. This tailing can be utilized as building and refractory material. This process is environmental friendly with zero waste.
• the inventive process can effectively produce two valuable products from the ultra fines of iron ore.
• One product is suitable for fine magnetic particle application or for peptization whereas the other product is suitable for refractory making, nano paint or nano coolant.
• Figure 1- schematically illustrates in the form of a flow-chart of the process steps according to the invention.
• the difference in surface charge of the iron bearing minerals and the gangue minerals is utilized first to separate out a first part of the gangue minerals present in the ultra fines.
• the materials from the first stage is subjected to a selective flocculation by adapting modified starch.
• the concentrate gets converted and suitable for use as the raw material for blast furnace, and the tailing containing high alumina and silica suitable for use as the building materials.
• a non-selective dispersion followed by a selective flocculation process is proposed to separate out different levels of iron containing ultra fines into (i) an iron rich concentrate, and (ii) a tailing having high level of clay and refractory materials.
• the ultra fines are processed according to the invention include the ground rejected material of various beneficiation processes and hydro cyclone over-flow.
• the processable iron containing ultra fines is the mixture of Fe, Si and Al oxides with different particle size.
• the alumina and silica level of each includes in the range of 2.5 to 14 wt%.
• the particle size of the ultra fines is in the range of 100 micron to lOOnm, and separated into coarser (more than 15 micron) and finer (less than 15 micron) categories, by adapting a hydro-cyclone of different sizes.
• the coarser particles are caused to undergo wet grinding under varied concentration to make it finer, finer particles being more suitable for the process because they offer better liberation and better floe formation.
• the dispersant used in the process includes different non-selective dispersant with different dosages for example, sodium silicate and sodium hexameta phosphate.
• the dosages of the dispersant are selected in the range of 20 to 150000 ppm, preferably in the range of 20 to 10000 ppm.
• the flocculant includes different starch solutions under varied dosage.
• the starch includes potato, wheat and maize.
• the starch solution comprises plain including caustic starch solution with varied concentration of caustic for example, in the concentration range of 0.1 to 10 wt%.
• the process can be implemented under varied pH conditions.
• the range of pH solution includes 2.5 to 11, preferably 8-10.
• the concentration of the ultra fines includes in the range of 2 to 25wt%, with varied settling time for example, between 10 seconds to 20 hours.
• the process includes different mixing processes to break agglomerated particles, the mixing process comprises magnetic stirring, mechanical stirring or mixing the ultra fines in solution using ultrasonic treatment.
• the ultrasonic treatment includes a treatment time in the range of 1 to 300 minutes under variable ultrasonic power.
• the solvent includes double distilled water, distilled water, tap water and industrial process water .
• the industrial process water includes different degree of contamination with different metallic and non- metallic ions and bacteria.

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• Manufacture And Refinement Of Metals (AREA)

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Cited By (2)

Citations (3)

• 2010
  • 2010-08-12 IN IN130KO2010 patent/IN2010KO00130A/en unknown
  • 2010-08-12 CN CN2010800068822A patent/CN102438755A/zh active Pending
  • 2010-08-12 CA CA2789308A patent/CA2789308C/en active Active
  • 2010-08-12 WO PCT/IN2010/000535 patent/WO2011099030A1/en not_active Ceased
  • 2010-08-12 AU AU2010330717A patent/AU2010330717B9/en not_active Ceased
• 2011
  • 2011-07-11 ZA ZA2011/05104A patent/ZA201105104B/en unknown

Patent Citations (3)

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