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

Definitions

• the present invention relates to a process for the treatment of a great variety of solid particulate materials so that the same will be easier to store, handle, transport or briquette and also so as to improve the storage qualities,
• coal dust and fine coal treated according to the present invention will be less subject to oxidation and briquettes formed thereof will have more equal and uniform surface characteristics and less binder, such as pitch, will be needed for forming such briquettes so that upon burning of the same less smoke will be produced.
• the present invention proposes a method of treating solid, particulate materials, which method comprising the steps of applying to a mass of solid particulate material an emulsion of a hydrophobic oil in a binder-containing aqueous liquid so as to form a mass consisting essentially of particles of the material with the hydrophobic oil and the binder adhering thereto, whereby it will be achieved that the surface characteristics of the particles of the material will become more uniform and individual particles will agglomerate to form larger particles, resulting in a mass which lends itself to be more densely packed than the initial particulate material.
• the method of treating solid particulate materials according to the present invention may comprise the step of applying to a mass of solid pulverulent material a hydrophobic oil and a binder-containing aqueous liquid so as to form a mass consisting essentially of particles of the material with the hydrophobic oil and the binder adhering thereto, whereby the particles of the mass will be agglomerated to form larger particles of substantially uniform surface characteristics.
• the treating of the solid particulate material comprises the step of forming an emulsion consisting essentially of between 60 and parts by weight of an aqueousliquid having between 4 and 39 parts by weight of a binder (dry material) selected from the group consisting of sulphite waste liquor, sulphite pulp powder, starch, dextrine, mastic, gum arabic, casein, glue, gum tragacanth, water glass and methyl cellulose distributed therethrough, and between 1 and 39 parts by Weight of a hydrophobic oil having a boiling point between and 400 C. dispersed in the aqueous binder-containing liquid, and forming an intimate mixture of 100 parts by weight of the solid particulate material and between /2 and 30 parts by weight of the binder-containing aqueous liquid.
• a binder dry material
• water-resistant binder materials such as cement and particularly pitch are mixed with the agglomerated material formed as described above. Mixing preferably is carried out under heating and is followed by pressing the thus-formed mixture into briquettes.
• binder namely pitch
• the particulate initial material when not treated according to the present invention would require between about 3% more pitch than the material pre-treated according to the present invention.
• Briquettes according to the present invention will contain only between about one-half and 2% by weight of the hydrophobic oil and an approximately equal percentage of the initial ibinder material plus between about 6 and 12% of pitch.
• the raw material costs of briquettes produced according to the present invention are lower than the corresponding costs of briquettes which are produced directly of the solid particulate starting materials and of a larger proportion of pitch, without being subjected to the agglomerating treatment of the present invention.
• the present invention is also concerned with a method of forming briquettes which method comprises the steps of forming an intimate mixture of a solid particulate material adapted to be briquetted and of an emulsion consisting essentially of between 1 and 39 parts by weight of a hydrophobic oil dispersed in between 60 and 95 parts by weight of water as an aqueous liquid, the water having between 4 and 39 parts by weight of binder distributed therethrough, so as to form a mass consisting essentially of agglomerated particles of the material with the hydrophobic oil and the binder adhering thereto, which agglomerated particles will have substantially uniform surface characteristics and are adapted to be packed more densely than the initial solid particulate material, mixing the thus-formed mass with a water-resistant binder, and briquetting the thus-formed mixture, whereby briquettes of highly uniform quality are formed.
• the present invention thus proposes to solve the problems involved in transforming fine-grained powdery materials of very different characteristics into easily manageable and treatable substances at relatively very low expenses. It has been found that by proceeding in accordance with the present invention it is possible to improve substantially those properties of the powdery substances which are essential for the further handling and processing thereof.
• pulverulent or powdery mass which may have a particle size of up to about 6 mm., for instance in the case of coal fines, or as small as about 1 micron, for instance in the case of the red dust formed in the LD oxygen blast process, with an aqueous emulsion consisting of between about 1 and 39% by weight, preferably of between 1 and 49% by weight of a hydrophobic oil such as a hydrocarbon oil, between 4 and 39%by weight, preferably between 4 and by weight, of a binder and between 60 and 95% of water.
• aqueous emulsion consisting of between about 1 and 39% by weight, preferably of between 1 and 49% by weight of a hydrophobic oil such as a hydrocarbon oil, between 4 and 39%by weight, preferably between 4 and by weight, of a binder and between 60 and 95% of water.
• Such emulsions are taken up, in a surprisingly short time, even by such powdery substances which are known for their bad wettability, so that in cany cases simple mixing of the pulverulent materials and the emulsion will be sufiicient to produce the required improvement, i.e., agglomeration of particles of the initial particulate pulverulent substance and greater uniformity of the surface characteristics thereof.
• any kind of pulverulent material having particle sizes up to about 6 mm. may be mixed with the above described emulsion and thereby the properties of the pulverulant material will be improved so that the same can be more easily handled or further processed, for instance more easily packed or conveyed.
• the method is of particular importance with respect to finely pulverulent materials having particle sizes of up to 50 microns or up to 200 microns or up to 3 mm.
• the thus pre-treated material may then be further processed by briquetting. In this connection, briquetting with the help of pitch as a binder material is particularly improved by the pre-treating treatment.
• Briquetting with the help of pitch is carried out by mixing the pro-treated agglomerated material with pitch in a suitable kneading device, and subsequent processing of the thus-formed mixture into briquettes.
• a suitable kneading device for briquetting purposes it is also possible in many cases to replace the pitch with other suitable materials, known per se in the art.
• briquettes formed of the agglomerated material produced according to the present invention are of more even quality and greater strength, notwithstanding the smaller proportion of pitch therein.
• the present invention is not limited with respect to briquetting to the use of pitch as the binder admixed for briquetting purposes. Any other binder materials conventionally used for briquetting purposes may also be employed in the briquetting of the agglomerated materials formed as described further above. If pitch is to be used as the briquetting agent, then preferably pitch having a softening point of between 50 and 75 C. according to Kraemer-Sarnow will be used.
• a thorough change of the typical properties of the particulate material such as a powder or dust will be accomplished by a small addition of the emulsion in accordance with the present invention.
• Addition of the emulsion in an amount of between 1 and 10% by weight of the pulverulent material usually will sufiice.
• additions of up to 20 or 30% of the weight of the finely pulverulent material may be suitable.
• the proportion of hyprophobic oil and binder in the emulsion will normally amount to not more than 10% altogether, the share of the oil being not higher than about 5% by weight of the pulverulent material.
• the binder in the emulsion may be sulphite waste liquor such as calcium sulphite waste liquor or ammonium sulphite waste liquor. These waste liquors are available as 1090%, preferably 4060% aqueous solutions. For instance, sulphite waste liquor of 35 B. contains 45% water and sulphite waste liquor of 29 B. contains 50% water.
• the emulsion with which the solid particulate and frequently finely pulverulent material is to be mixed according to the present invention will contain between 4 and 39% binder, most preferably between 10 and 30% thereof, and between 1 and 39% hydrophobic oil, most preferably between 5 and 20% of the hydrophobic oil, the balance being water to which possibly an emulsifying agent might be added.
• the emulsion may be admixed in amounts of between 1 and 15% by weight.
• proportions of the emulsion such as between 5 and 15% are admixed, while material of larger particle size, such as material having a particle size of between about 1 and 6 mm. will require relatively smaller proportions of the emulsion, for instance between 1 and 10% thereof.
• the powdery product previously will have been subjected to another process, e.g., grinding or thermal treatment. These previous operational steps always will lead to a partial change at least of the surfaces of the original material.
• the changes may be of a physical or also of a chemical nature, e.g., opening of pores, oxidation or absorption of gas.
• fine grained and powdery materials are characterized in almost every case by very great differences in their surface properties. This leads to difficulties, especially when it is necessary to wet or to coat these unhomogeneous materials with relatively small quantities of a liquid. It is extremely diflicult uniformly to wet large and non-uniform surfaces areas with a small quantity of liquid.
• the application of the emulsion, according to the present invention will permit to wet large and non-uniform surface areas rapidly, evenly and at low cost.
• the surfaces of the thus-wetted particulate product are protected against deteriorating effects during transport and storage. For instance, such coal fines which are prone to selfignition by oxidation duringstorage, when treated with an emulsion according to the present invention, will practicallyno longer be subject to self-ignition.
• the treatment with the emulsion will prevent unpredictable difficulties previously caused by the uneven, non-uniform surface characteristics, and the treated material not only will be more easily manageable, but will be transformed into a product having homogeneous surface properties.
• the process according to the invention is particularly suitable for dusts and extremely fine materials, particularly for substances with a medium grain size down to 200 or 100 and even to below 1 micron, but the process can be applied also without any difficulties to materials which consist completely or partially of coarser particles up to 1-3 mm. or more. It is applicable .to all kinds of ma- 6 terials which are not soluble in water, including fine coal particle sizes of 0-3 mm., 0-6 mm. or the like.
• Any hydrophobic oil and especially hydrocarbon oils may be used for forming the emulsion, e.g., paraffinic, naphthenic or aromatic hydrocarbons.
• the choice between the oils can be guided, therefore, by economic considerations, keeping in mind the intended further processing of the thus-treated material.
• water-soluble binder will depend primarily on its price. All water-soluble binders are suitable, e.g., sulphite waste liquor, sulphite pulp powder, starch dextrines, mastic, gum-arabic, casein, glue, tragacanth, water glass, methyl cellulose and other natural or synthetic substances which in form of their aqueous solutions have agglutinating properties.
• All water-soluble binders are suitable, e.g., sulphite waste liquor, sulphite pulp powder, starch dextrines, mastic, gum-arabic, casein, glue, tragacanth, water glass, methyl cellulose and other natural or synthetic substances which in form of their aqueous solutions have agglutinating properties.
• the stability of the emulsion can be improved by addition of well-known emulsifying agents, especially if the emulsifying effect of the binder is to be improved.
• emulsifying agents give good results: sodium or potassium soaps, fatty alcohol sulfonates, alkyl sulfonates or alkyl-naphthyl sulfonates, ethanolamines, technical albuminous products and the like.
• the process may be carried out in .a simple and economical manner. Since the finely sub-divided powdery substance will absorb the emulsion easily, the entire surface of the powder is wetted or coated in an extremely short time; as a rule, a short thorough mixing of the emulsion and the powder will be sufficient, under certain conditions a few seconds, or up to 10 minutes at the most. It goes without saying that the mixing time depends on the type of mixing apparatus available. The usual simple mixers will give satisfactory results in many cases. Very suitable are mixers with kneading appli ances and all types of intensive mixers and homogenizing machines, for instance machines mixing in the manner disclosed in US. Patents to Reerink et al. Nos.
• the thorough mixing of the emulsion and of the solid material can be facilitated by previously increasing the volume of the emulsion.
• air is stirred into the emulsion, either when the emulsion is prepared or later on, "immediately before its use. 'As a result of the aeration, the volume of the emulsion will reach twice to five times its original volume.
• emulsion for instance, to add to 100 parts by weight of the pulverulent material 10 parts by weight of an oil in water emulsion containing between about 0.1 and 39 parts by weight of hydrocarbon oil and between 0.4 and 39 parts by weight of the binder as well as a suitable amount of water. If the solid particulate material already contains an appreciable proportion of water, then a more concentrated emulsion may be admixed so that the aforesaid composition of the emulsion in the mass is reached. It is also possible to produce and store the emulsion in a more concentrated form and to dilute the same with water prior to or during use.
• Another advantageous application of the present invention will be found in cases where during storage, etc., dust formation will occur.
• Treatment according to the present invention will serve to prevent undesirable changes in the surface particles of such newly formed dust.
• the process of the invention is also useful for binding and agglomerating very fine flue dust.
• admixture of the emulsion will cause formation of protective layers covering the surfaces of material and preventing or at least reducing oxidation or other harmful changes thereof.
• admixture of the emulsion in accordance with the present invention will also serve to protect pulverulent materials which during storage are exposed to atmospheric conditions, against the adverse elfects of such exposure.
• the application of the emulsion will cause formation of protective coatings on the surface of the thus-treated pulverulent material.
• compositions of the emulsion are described below by way of example only (all percent by weight):
• COMPOSITION I Percent Sulphite waste liquor (from fir) 33 B 20 Anthracene oil 20 Water 60 COMPOSITION II Sulphite waste liquor (from beech) 29 B. 30
• COMPOSITION IV Cane sugar molasses 8 Tar oil Water 80 COMPOSITION V Water glass 8 Sulphite waste liquor 15 Anthracene oil 6 Water 74 COMPOSITION VI Methyl cellulose 6 Ammonium lignin sulphonate 6 Light oil 1 Water 87 COMPOSITION VII (Concentrated emulsion to be diluted before use or to be used for treating particulate material of high water content) 8 COMPOSITION VIII I Casein 25 Linseed oil 2 Alkylnaphthylsulphon ate 0. 1 Water 72.9
• coking fines in accordance with the present invention are intensively mixed with 6% (based on the weight of the coking fines) of an emulsion consisting of 15 parts by weight of ant hracene oil of a boiling range of between 195 and 360 C. dispersed in a mixture of 15 parts by weight of sulphite waste liquor of 31 B. and 70 parts by weight of 'water, the quality remains unimpaired.
• the percentage of fines having a size below 0.1 mm. is reduced from 28 %to 8%, and the thus treated coke fines can be stored exposed to air without appreciable reduction in its coking quality.
• EXAMPLE II Iron ore dust originating from a thermal ore dressing plant and including by weight of particles having a size below 0.06 mm. is to be charged into railroad cars. Charging of the ore dust in its original condition is nearly impossible due to heavy dust formation and losses. However, after mixing the ore dust in a whirling mixer for five mixtures with 10% of an emulsion consisting of 2 parts of fuel oil, 10 parts of molasses and 88 parts of water, the thus-treated ore dust can be handled and transported without difficulty.
• EXAMPLE III Blast furnace fine dust containing a high proportion of very fine particles is to be agglomerated by addition of cement and bentonite.
• the flue dust is mixed for three minutes in an intensive mixer with 8% of an emulsion consisting of 3 parts of fuel oil having a boiling range of between and 320 C., 10 parts of starch paste containing 50% starch, and 87 pants of water. Thereafter, 10% cement and 3% bentonite are added and the thus-formed mixture is then shaped and burned at a temperature of 1000 C. into bricks of great hardness.
• the aerated emulsion is produced by mixing the components thereof in a Turax intensive mixer until, due to the incorporation of air, the volume of the mixture has been increased three fold. This might require mixing for about twenty minutes.
• the thus-agglomerated coal dust is mixed with 5% by weight of pitch and pressed to form briquettes, and in this manner briquettes of excellent quality and strength are obtained.
• EXAMPLE VI Iron powder of a grain size range below 0.075 mm. is to be shaped into solid and uniform briquettes, using as little binder material as possible.
• the thus-formed mixture After thorough mixing for 6 minutes inan intensive kneading mixer with 5% of an emulsion consisting of 10 parts by weight of fuel oil having a boiling range of between 150 and 350 C., 20 parts of molasses and 70 parts of water, the thus-formed mixture is briquetted at a pressure of 4,000 kg/cm The thus-formed briquettes are of uniform strength and density.
• EXAMPLE VII An anthracite coal having a particle size of up to 3 mm. is dried so as to have a residual water content of 2.5%. Thereafter, the particulate anthracite coal is intimately mixed with 1% by weight of an emulsion consisting of 40% tar oil, 30% sulphite waste liquor containing 50% dry substance, and 30% water. Due to the residual water content of the coal, the total water now available will be equal to about 5 times the amount of water admixed with the emulsion, and an even distribution of the oil in water emulsion on the surface of the anthracite particles will be achieved under formation of agglomerations of anthracite particles.
• the thus-agglomerated anthracite coal is then intimately mixed with 5.5% by weight of tar pitch and compressed in a conventional press into briquettes.
• the thus-formed briquettes have a smooth and even surface texture, are resistant against abrasion and develop relatively little smoke upon burning, considerably less than briquettes produced of the same type of anthracite coal without the admixture of the emulsion and 'with between 7 and 9% of tar pitch, i.e., the percentage which will be required for briquetting such anthracite coal if the same has not been previously agglomerated as described herein.
• EXAMPLE VIII A semibituminous coal at a temperature of 70 C. and a particle size of less than 1 mm. 45% being less than .1 min, and a water content of 1.5% was mixed with 3% of an emulsion consisting of 20 parts tar oil, 30 parts sulphite waste liquor (55% solids) and 50 parts water in a continuous kneading mixer and subsequently mixed with 5% of ground briquetting pitch, led through a double mixer neck into a steam kneader and b'riquetted in a roll press. Notwithstanding the fineness of the initial coal and the small content of binding material, the breaking strength was between 80 and 105 kg.
• EXAMPLE IX An iron dust with a fineness of 100% less than micron and 70% less than 1 micron was intimately mixed with an emulsion consisting of 33 parts anthracene oil, 33 parts sulphite waste liquor containing 50% solids and 34 parts water, and subsequently mixed with 8% ground briquetting pitch. This briquetting mixture was compressed to form nut briquettes in a double roll press. The breaking strength of the briquettes was 70-80 kg.
• a briquetting process has become possible only by the pretreatment of the fine ore dust with emulsion. Without such pretreatment it is impossible to mix the fine ore dust with pitch.
• EXAMPLE X A coke dust at a temperature of 65 C., having a water content of 0.2%, a grain size less than 1 mm. with 59% less than 0.2 mm., was mixed with an emulsion consisting of 10 parts of oil, 20 parts of sulphite lye waste liquor of 50% solids content and 70 parts Water, and was then formed into nut briquettes together with 8% of briquetting pitch by means of a steam kneader and a roll press. The briquettes possessed at normal temperature a breaking strength of 185 kg. and at 1,000 C., heated in annealing condition, a breaking strength of 140 kg.
• EXAMPLE XI 50 parts of soot were intimately mixed with 40 parts of baking mineral coal (a very pure coal with 0.4% ash and 4% moisture) and 4% of an emulsion consisting of 25 parts of anthracene oil, 35 parts of a 50% solids content sulphite lye waste liquor and 40 parts of water.
• the mixture was subsequently treated with 7% ground briquetting pitch in a steam kneader and pressed into shaped.
• By carbonization a porous hard pressed shape was obtained with a specific electrical resistance of about 120 ohms per mmF/m.
• a method of treating solid particulate material having non-uniform surface characteristics and selected from the group consisting of solid carbonaceous materials, sand, flue dust, and ore and metal powders, and having a particle size of up to about 6 mm. comprising the steps of forming an intimate mixture of 100 parts by weight of said solid particulate material and between /2 and 30 parts by weight of an oil in water emulsion consisting essentially of between 1 and 39 parts by weight of a hydrophobic oil in between 60 and parts by weight of water having between 4 and 39 parts by weight of a water-soluble binder dissolved therein, so as to form a mass consisting essentially of particles of said material with said hydrophobic oil and said binder adhering thereto, whereby a pulverulent material will be formed consisting of particles of more uniform surface characteristics than said solid particulate material, adapted to be packed more densely than said solid particulate material and also adapted to be briquetted upon admixture of a water-insoluble binder; mixing the
• a method of treating solid particulate material having non-uniform surface characteristics and a particle size of up to about 200 microns comprising the steps of forming an intimate mixture of parts by weight of said solid particulate material and between V: and 30 parts by weight of an oil in water emulsion consisting essentially of between 1 and 39 parts by weight of a hydrophobic oil in between 60 and 95 parts by weight of water having between 4 and 39 parts by weight of a water-soluble binder dissolved therein, so as to form a mass consisting essentially of particles of said material with said hydrophobic oil and said binder adhering thereto, whereby a pulverulent material will be formed consisting of particles of more uniform surface characteristics than said solid particulate material, adapted to be packed more densely than said solid particulate material and also adapted to be briquetted upon admixture of a water-insoluble binder; mixing the thus formed mass with a water resistant binder in an amount sufiicient to permit briquetting of the thus formed mixture; and
• a method of treating solid particulate carbonaceous material having non-uniform surface characteristics and a particle size of up to 6 mm. comprising the steps of forming an intimate mixture of 100 parts by weight of said solid particulate carbonaceous material and between /2 and 30 parts by weight of an oil in water emulsion consisting essentially of between 1 and 30 parts by weight of a hydrophobic oil in between 60 and 95 parts by weight of water having between 4 and 39 parts by weight of a water-soluble binder dissolved therein, so as to form a mass consisting essentially of particles of said material with said hydrophobic oil and said binder adhering thereto, whereby a pulverulent material will be formed consisting of particles of more uniform surface characteristics than said solid particulate material, adapted to be packed more densely than said solid particulate material and also adapted to be briquetted upon admixture of a water-insoluble binder; mixing the thus formed mass with pitch as a water-insoluble binder in an amount sufficient to permit briquetting of
• a method of treating solid particulate carbonaceous material having non-uniform surface characteristics and a particle size of up to 6 mm. comprising the steps of forming an intimate mixture of 100 parts by weight of said solid particulate carbonaceous material and between /2 and 30 parts by weight of an oil in water emulsion consisting essentially of between 1 and 39 parts by weight of a mineral oil in between 60 and 95 parts by weight of water having between 4 and 39 parts by weight of a water-soluble binder selected from the group consisting of sulphite waste liquor, sulphite pulp powder, starch, dextrine, mastic, gum arabic, casein, glue, gum tragacanth, water glass and methyl cellulose, dissolved therein,
• a pulverulent material will be formed consisting of particles of more uniform surface characteristics than said solid particulate material, adapted to be packed more densely than said solid particulate material and also adapted to be briquetted upon admixture of a water-insoluble binder; mixing the thus formed mass with pitch as a water-insoluble binder in an amount sufficient to permit briquetting of the thus formed mixture; and briquetting the thus formed mixture, whereby briquettes of highly uniform quality are formed.
• a method of treating solid particulate material of non-uniform surface characteristics and selected from the group consisting of solid carbonaceous materials, sand, flue dust, and ore and metal powders, and having a particle size of up to about 6 mm. comprising the steps of forming an intimate mixture of 100 parts by weight of said solid particulate material and between /2 and 30 parts by weight of an oil in water emulsion consisting essentially of between 1 and 39 parts by weight of a hydrophobic oil in between and parts by weight of water having between 4 and 39 parts by weight of a water-soluble binder dissolved therein, so as to form a mass consisting essentially of particles of said material with said hydrophobic oil and said binder adhering thereto, whereby a pulverulent material will be formed consisting of particles of more uniform surface characteristics than said solid particulate material, adapted to be packed more densely than said solid particulate material and also adapted to be briquetted upon admixture of a Water-insoluble binder; mixing the thus

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Cited By (17)

Citations (8)

• 1960
  • 1960-10-12 BE BE595949A patent/BE595949A/fr unknown
• 1963
  • 1963-02-28 US US261885A patent/US3307927A/en not_active Expired - Lifetime

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