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
  • C22B1/14—Agglomerating; Briquetting; Binding; Granulating
  • C22B1/24—Binding; Briquetting ; Granulating
  • C22B1/242—Binding; Briquetting ; Granulating with binders
  • C22B1/243—Binding; Briquetting ; Granulating with binders inorganic
• • 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
  • B01J2/00—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic
  • B01J2/28—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic using special binding agents
• • 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
  • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
  • B01J37/0009—Use of binding agents; Moulding; Pressing; Powdering; Granulating; Addition of materials ameliorating the mechanical properties of the product catalyst

Definitions

• This invention is related to a process bonding agglomerates of particles of preferably inorganic materials.
• the invention is characterized by the inclusion into agglomerates of fibres, namely of inorganic materials, such as mineral fibres which may consist of glass fibres, rockwool fibres, slag wool fibres, etc.
• inorganic materials such as mineral fibres which may consist of glass fibres, rockwool fibres, slag wool fibres, etc.
• fibres of rockwool,stonewcol, or slagwool type are used, prepared e.g. by melting basalt, greenstone, diabase or similar minerals or species of stone, or slag, e.g. with the addition of lime, dolomite or similar materials.
• fibres as a binder for agglomerates can be practiced for a plurality of particle types, especially of inorganic materials, especially ores and ore concentrates, such as iron ores, e.g. hematite, magnetite or other iron oxide materials comprising one or more of the oxides FeO,
• Fe 3 O 4 and Fe 2 O 3 as well as other iron oxide materials, such as hydrated oxides, etc.
• Suitable materials are ores of nickel, cobalt, copper, zinc, lead, tungsten, etc. as well as other materials in agglomerated form, e.g. catalyst materials or carriers for catalyst materials, such as alumina.
• the grain size of the agglomerated material may vary within broad limits, e.g. up to 1 mm or up to 0.5 mm, preferably up to 0.1 mm, up to 0.05 mm or up to 0.01 mm.
• the lower limit may also vary within broad limits, e.g. down to 0.1 mm, down to 0.05 mm, down to 0.01 mm or down to 0.001 mm.
• the upper and lower limits resp. may relate to 100 % of the material but also to a range of e.g. 90 %, 75 % or 50 % of the weight of the material.
• finer or coarser materials may, however, be included in the agglomerates, provided that said materials can be agglomerated.
• Agglomeration methods of various types may be used, preferably rolling of particled materials to balls or pellets in devices comprising drums, cones or discs.
• Agglomeration by rolling to bolls is usually performed with the addition of a liquid, preferably water or an aqueous solution of organic or inorganic materials.
• a liquid preferably water or an aqueous solution of organic or inorganic materials.
• binders which are commonly used for agglomeration, such as organic glues of various types, especially polymeric materials, such as cellulose and cellulose derivatives, starch materials, curable resins, etc., and inorganic additives, such as bentonite or other clays, lime, cement, such as Portland cement, slag cement, alumina cement.
• the quantity of said binders may be maintained within the normally used ranges or may be decreased, e.g. to not above 50 or 20 % of the quantities normally used. Fibres which are chemically resistent against cement can be us
• fibres when used in relation to this invention is intended to include elongated bodies having an extension in the longitudinal direction of at least 5, preferably at least 10 times the extension in any other direction perpendicular thereto.
• the cross section shape perpendicularly to the longitudinal direction may vary depending upon the method of production but is preferably about circular or with a ratio largest diameter:smallest diameter in the cross section, passing through its point of gravity of not above 5:1, preferably not above 3:1 and especially not above 2:1.
• the average diameter of the fibres perpendicularly to the longitudinal direction may vary within broad ranges depending upon the method of production.
• at least 90 % of the fibres have a thickness below 1 mm, especially below 0.5 mm and particularly below 0.1 mm or below 0.05 mm.
• a common upper limit of the thickness is 0.025 mm or even 0.015 mm, sometimes 0.005 mm.
• the percentage figures may be based on the longitudinal extension of those parts of the fibres having a diameter within said ranges.
• Common values of average fibre diameter for mineral fibres are 1 - 10 microns and especially about 2 - 8 microns, particularly about 5 microns.
• the lenght of the fibres may vary depending upon the material to be agglomerated. Common upper limits for 100 % and especially 90 % of the fibre quantity is up to 20 mm or up to 10 mm but also shorter fibres such as up to 5 mm, up to 3 mm, up to 1 mm or up to 0.5 mm may be used, in which case preferably at least 50 % and especially at least 90 % of the fibres are shorter than said upper limit values.
• the fibre length is adapted together with the fibre diameter for the forming method used.
• the lower limit of the fibre diameter is often 0.1 mm, 1 mm and preferably 5 mm, said lower limits preferably being the lower limit of at least 50 % and preferably at least 90 % of the amount of fibres.
• the fibres can be prepared e.g. by forming a melt to fibres by drawing through spinning nozzles, by. forming a stream of a melt to fibres with a rotating drum, rotating disc, rotating wheel,, by blowing a stream of melt to fibres or by combining said methods, such as desintegration of a stream of melt on a wheel or a disk combined with blowing through nozzles.
• composition of mineral fibres may be varied within broad limits and examples of suitable ratios are stated in the following table:
• fibres of rockwool type prepared from basic rocks, e.g. greenstone, basalt, diabase, optionally with addition of lime or dolomite, preferably in a quantity of up to 30 %, e.g. 10 to 20 % by weight.
• Said fibres may have the following chemical composition in % by weight: SiO 2 45, Al 2 O 3 14, CaO 20, MgO 7, FeO 6.
• the contents of said constituents may vary with - 5 %, preferably - 10 % of the content values stated above.
• Other constituents may consist of other oxides, such as MnO , Na 2 O , K 2 O , TiO 2 , BaO , B 2 O 3 , etc .
• the quantity of fibres in the agglomerates preferably is not above or up to 20 % by volume, especially not above 10 % by volume and particularly not above 5 % by volume, but also lower contents, such as not above 2 % by volume or not above 1 % by volume can be used.
• the lower content limit is preferably at least 0,01 % by volume, especially at least 0,05 and particularly 0,1 % by volume, but also higher contents, such as 0,5 or 1 % by volume can be used as lower content limits.
• Suitable content ranges are e.g. 0,1 - 5 and especially 0,25 - 2,5 % by volume. Said values are based on the solid materials . volume of the agglomerate particles and the fibres .
• the agglomerated particles preferably are of a comparatively spherical shape, e.g. with a difference between the largest and smallest dimension (especially diameters passing through the middle point or point of gravity) of in average not above 5:1.
• the fibres can be included homogeneously within the entire volume of the agglomerates or can be distributed with differing fibre density within various parts of the agglomerates, e.g. within average more than 50 % or 75 % of the fibre volume within an outer layer comprising less than 50 % or less than 25 % of the volume of the particle.
• the direction of the fibres within the agglomerates may be random or directed or arranged in layers. More than 50 and especially more than 75 % by volume of the fibres may be directed radially or within 30° from a radial direction in the agglomerates or may be directed tangentially or within 30 or 60 from a tangential direction in the agglomerates if the shape of said agglomerates is approximated with the shape of a sphere.
• the agglomerates may also comprise at least 25, e.g. at least 50 and also at least 75 % by volume of the fibres distributed within more than one and preferably two or three concentric layers. Preferably the fibres within said layers are arranged randomly or predominantly tangentially, e.g.
• Said layers comprise preferably at least 10 %, e.g. at least 25 % or at least 50 % of the total agglomerate volume, and each of said layers preferably comprises at least 5 %, e.g. at least 10 % or at least 25 % of the volume of the agglomerate.
• the extension in the thickness direction of said layers in relation to the radial extension of the agglomerates may also be at least 5 %, e.g.
• Said values can be related to layers comprising fibres which are arranged alternating with layers free from fibres, or be related to layers with increased content of fibres in relation to adjacent layers.
• the size of the agglomerates, especially agglomerates prepared by rolling balls (balling) may amount to e.g. not above 50 mm, preferably not above 40 mm and especially not above 30 mm and optionally particularly not above 15 mm in diameter.
• the lower limit of the diameter of the agglomerates may also be e.g. above 2 mm, preferably above 5 mm and especially above 8 or 10 mm. Suitable ranges are especially for iron ore balls, e.g. 5 - 20 mm or 10 - 30 mm.
• the fibres may be added entirely or partly to the starting material which is subjected to agglomeration, e.g. rolling (balling), e.g. added to an aqueous suspension or pulp of particles prior to dewatering, e.g. fine iron ore particles prior to dewatering, after grinding or remediation or optionally in the beneficiaation step.
• Fibres added to an aqueous suspension of particles may facilitate the removing of liquid, e.g. dewatering of an aqueous suspension of an ore concentrate.
• the fibres may also be added entirely or partly prior to or during the agglomeration step, especially rolling to balls (balling).
• fibres may be added in one or more of the ball rolling (balling) steps or between the ball rolling steps.
• Fibres may suitably also be added in a later part of a ball rolling step, e.g. close to the outlet from the step so that the fibres are included in the outer part of the agglomerate layer applied in said step, e.g.
• the agglomeration device may also be operated so that the larger agglomerates in the charge are concentrated in a part of the charge, preferably at the surface of the charge, in which case the fibres may be added preferably to the larger or nearly ready agglomerates (balls).
• fibres of different composition and/or dimensions such as thickness and lenght, uniformly and homogeneously within the agglomerates (the expression “agglomerate” comprises in this connection as well as in other connections covered by this invention also balls or pellets,.incl. micropellets ⁇ 6-8mm, made by rolling) or uniformly distributed within the same layer of the agglomerates, or optionally fibres of different composition and/or dimensions may be used within different parts of the agglomerates.
• the fibres may comprise fibres with a low melting point or softening point, preferably below 1000oC and especially below 800°C, e.g.
• fibres with low softening point which makespossible good bonding to the particles at a low temperature are distributed within an outer part of the agglomerates, optionally together with fibres of high softening point, in order to make certain that good bonding at low temperatures is obtained, especially low temperature reduction of the outer part of the iron ore pellets after sintering at low temperature.
• the fibres may be added to the agglomerates with production of the fibres in immediate vicinity to the point of addition, e.g. the agglomerating device, and transport of the fibres produced directly to said point, e.g. by air or gas transportation.
• the added or applied powderous material may be used for increasing the friction between the fibres and the agglomerated particulate material or may consist of a material which when heated or under the influence of humidity acts as a binder between the fibres and the agglomerated material.
• powderous materials which can be added to the fibres are silica, water glass and lime.
• a fibre composition which makes it possible to leave out slag forming constituents entirely or partly from the agglomerates or from the charge in which said agglomerates are included.
• onm may produce e.g. so-called self-fluxing balls or pellets having a desired ratio (Ca,MgO):SiO 2 (basicity).
• the basicity may be low (acid balls or pellets), e.g. 0 - 0.5 or up to 0.8 or 1.0, average basicity, e.g. 0.5 - 1.5 or 0.8 - 1.2, and high basicity, e.g. 1.0 - 2.0 or above, e.g.
• the ratio CaO:CaO+MgO may vary e.g. from 1 to 0.2 or from 0.9 to 0.4, e.g. from 0.8 to 0.5.
• rockwool fibres prepared from a basaltic rock with a softening point of about 1000 - 1100°C. are added. Said fibres are prepared by desintegrating a stream of melt on a rapidly rotating disc and exhibits an average fibre diameter which is essentially within the range 1 - 5 microns. The fibres are added to the magnetite concentrate A) prior to the addition to the pelletizing drum (ball rolling drum)
• bentonite in a quantity of about 0.5 and especially 1 % under the conditions stated above is tested and the good results are maintained, and improved.
• balls were prepared by the method stated above from hematite ore concentrate and magnetite ore concentrate with a reducing agent mixed into the balls and with the addition of fibre material of the types stated above.
• the quantity of reducing agent was in this case varied between 20 and 200 % of the quantity required for complete reduction and comprised in various different cases 20, 40, 75, 100, 150 resp. 200 % of said quantity.
• As a reducing agent coke breeze and coal breeze were used.
• balls prepared according to the invention from iron ore concentrates were tested for use in various metallurgical processes, such as the blast furnace process, the electro steel furnace processes, oxygen blast processes, such as the LF-process, the caldo process, the Thomas process, the Martin process.
• Balls according to the invention with a high content of reducing agent may also be used for direct reduction processes in which the reducing agent in the balls contributes to reduction, e.g. reduction processes performed in a rotating furnace or a shaft furnace.
• the produced balls which may or may not comprise reducing agents and may or may not comprise cold bonding agents (cold binders) and with or without a preliminary sintering are also suitable for various types of direct reduction processes performed with a reducing gas, such as the Wiberg-process, the HL-process and similar processes, in which case the reduction may be performed in a moving or stationary bed, e.g. in a shaft furnace or in charge-wise charged furnaces in which the ball or pellet bed is maintained stationary in the- reduction step.
• a reducing gas such as the Wiberg-process, the HL-process and similar processes
• the fibre* material may optionally partly and preferably to at least 50 % exhibit a high softening point exceeding 1000oC and especially exceeding 1100 or 1200°C in order to counteract a tendency of the balls to sag, shrink and agglomerate in theproduction step, especially at 1000 - 1100°C.
• the composition oi fibre material is.adapted so that the material at higher temperatures, e.g. above 1200 and above 1300oC gives rapid melting within a restricted temperature range.
• balls (pellets) and other agglomerated or sintered products according to the invention comprising the fibre materials referred to as strenght increasing agent or fortifying agent and porosity improving agent may be.
• strenght increasing agent or fortifying agent and porosity improving agent may be used as substitute for balls (pellets) and agglomerated products of iron ore concentrates and similar, such as roasted pyrites, in the quantities and in the manner in which such previously used products have previously been used.
• furnaces in which products according to the invention can be used can be made to blast furnaces in which heat is involved by burning a fuel, electric blastfurnaces, electric pigiron furnaces, optionally with prereduction, such as prereduction in a rotating furnace or shaft furnace, low shaft furnaces, melt reduction furnaces, LD-converters and other furnaces operating with injection of oxygen or other oxidizing gases, optionally in combination with or together with protective gases, such as argon, water vapour, hydrocarbons and similar, injected . against the surface of the charge and/or through nozzles arranged under the level of the melt especially in the furnace bottom. Examples thereof are the caldo furnace and the dored furnace.
• references may, in addition to the materials mentioned above also be made to ores and minerals comprising chromium, aluminum, manganese, vanadium, uranium, tin, antimony, bismuth, silver and gold.
• the process according to the invention is especially suited also for the production of chromium by a process which comprises the preparation of agglomerates from various kinds of chromium ores, e.g. by ball rolling (balling, pelletizing) or briquetting, comprising fibres according to the invention in the quantities mentioned above, e.g. the Cobond-process comprising autoclave leaching at about 200°C.
• fibres according to the invention can also be used for all the materials and minerals stated above in a dewatering step, e.g. by filtering or suction filters and similar devices, when forming the agglomerates, e.g. by ball rolling (balling, pelletizing) or briquetting, e.g. in briquetting presses or by extrusion, the fibre material being included homogeneously or in layers in various manners as disclosed above.
• the inclusion of a fibre material may also be used for facilitating processes comprising contact with a liquid, such as leaching minerals from the metals stated above or removing unwanted constituents or for recovering dissolvable desired constituents, e.g. by leaching with acid or basic compounds, optionally after a preceeding heat treatment, such as oxidation or reduction by heating in oxidizing or reducing environment.
• fibres in agglomerates of iron ore and also in other agglomerated products it is for commercial reasons suitable to reduce the content of fibres, preferably to less than 2 or 1 % by volume, especially to not above 0.5 or optionally not above 0.25 % by volume and especially to less than 0.1 % by volume, said contents being related to the real dry volume of solid materials.
• an agglomerate e . g . rolled balls or pellets , especially from iron ore it may be preferable at least 25 % , preferably at least 50 or 75 % of or optionally the entire fibre quantity to the particles prior to forming the agglomerate , e . g . immediately prior to the formation of the agglomerates or into a wet pulp prior to or after dewatering .
• Metallurgical slags can be used for making the fibres , e.g. a slag with a higher purity level then the slag normally formed in the process for which the bonded agglomerates are intended to be used as starting material or additive , e.g. slag from an electro-steel furnace e.g. when producing agglomerates of e.g. iron ore for e.g. a blast furnace charge or a steel furnace charge.
• an electro-steel furnace e.g. when producing agglomerates of e.g. iron ore for e.g. a blast furnace charge or a steel furnace charge.
• slag types which can be used for forming fibres suitable for this invention are blast furnace slags, Thomas process siags, slags , Siemens-Martin slags, copper shaft furnace slags, lead shaft furnace slags , etc.
• Examples of composition ranges are stated in the table below in which the figures relate to composition in % by weight. The rest of the composition up to 100 % may consist of other oxides.
• the fibres may be combined with other measures or means for bonding agglomerates, such as bonding by heating to hich temperatures,e.g. by heating to above 500, 700, 800 , 900 or 1000°C in which case it is often possible to reduce the bonding temperature with at least 50, preferably at least 100 or at least 200°C c ⁇ rpared with the temperature normally used for bonding the same agglomerates without fibres.
• bonding by heating to hich temperatures, e.g. by heating to above 500, 700, 800 , 900 or 1000°C in which case it is often possible to reduce the bonding temperature with at least 50, preferably at least 100 or at least 200°C c ⁇ rpared with the temperature normally used for bonding the same agglomerates without fibres.
• bonding by heating to hich temperatures e.g. by heating to above 500, 700, 800 , 900 or 1000°C in which case it is often possible to reduce the bonding temperature with at least 50, preferably at least 100 or
• hydrothermal bonding comprising a hydrothermal reaction especially at temperatures up to 200, 300, 400 or 600oC with constituents in the agglomerated material and/or the fibres.
• Fluthermore hydraulic binders e.g. cement, such as portland cement may be combined with the addition of fibres according to the invention, e.g. the "type and amounts of binders used in the so called "Grangcold" method.
• Suitable contents e.g. for preparing iron compound agglomerates are e.g. 0,05- 0,1 to 5 and especially 0,5 to .3% byweightof fibres and 1 to 20,e.g from 2, 4 , 6 or 8 up to 20,15 , 10, 8 , 6 or 4 % by weight of cement.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Materials Engineering (AREA)
• Geology (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Environmental & Geological Engineering (AREA)
• Life Sciences & Earth Sciences (AREA)
• Manufacturing & Machinery (AREA)
• Inorganic Chemistry (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Manufacture And Refinement Of Metals (AREA)
• Glanulating (AREA)
• Solid-Sorbent Or Filter-Aiding Compositions (AREA)
• Package Frames And Binding Bands (AREA)

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• 1980
  • 1980-05-16 JP JP50123680A patent/JPS56500693A/ja active Pending
  • 1980-05-16 WO PCT/SE1980/000144 patent/WO1980002566A1/en not_active Application Discontinuation
  • 1980-12-01 EP EP80901201A patent/EP0028649A1/en not_active Withdrawn
• 1981
  • 1981-01-16 NO NO810147A patent/NO810147L/no unknown

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