CA1196012A - Method and apparatus for separating oily and fatty materials from solid particles - Google Patents
Method and apparatus for separating oily and fatty materials from solid particlesInfo
- Publication number
- CA1196012A CA1196012A CA000416647A CA416647A CA1196012A CA 1196012 A CA1196012 A CA 1196012A CA 000416647 A CA000416647 A CA 000416647A CA 416647 A CA416647 A CA 416647A CA 1196012 A CA1196012 A CA 1196012A
- Authority
- CA
- Canada
- Prior art keywords
- froth flotation
- mill scale
- grinder
- solid particles
- flotation device
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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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
- C22B1/005—Preliminary treatment of scrap
-
- 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
- B03B—SEPARATING SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS
- B03B9/00—General arrangement of separating plant, e.g. flow sheets
- B03B9/02—General arrangement of separating plant, e.g. flow sheets specially adapted for oil-sand, oil-chalk, oil-shales, ozokerite, bitumen, or the like
-
- 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
- B03D1/00—Flotation
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
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- Chemical & Material Sciences (AREA)
- Geology (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Geochemistry & Mineralogy (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Separation Of Solids By Using Liquids Or Pneumatic Power (AREA)
- Extraction Or Liquid Replacement (AREA)
- Crushing And Grinding (AREA)
- Detergent Compositions (AREA)
- Cereal-Derived Products (AREA)
- Fats And Perfumes (AREA)
Abstract
ABSTRACT
A method and apparatus for separating oily and fatty materials from solid particles to which they are attached wherein the solid particles are subjected to controlled mechanical attrition and the resulting particles are then subjected to at least one froth flotation process with a washing liquid. The cleaned solid particles from the flotation process are separated from the washing liquid.
The oily and fatty materials are separated from the effluent of the froth flotation process to produce a clarified wash liquid which can then be recycled for further use in the process, particularly as a pre-wash liquid for the particles.
A method and apparatus for separating oily and fatty materials from solid particles to which they are attached wherein the solid particles are subjected to controlled mechanical attrition and the resulting particles are then subjected to at least one froth flotation process with a washing liquid. The cleaned solid particles from the flotation process are separated from the washing liquid.
The oily and fatty materials are separated from the effluent of the froth flotation process to produce a clarified wash liquid which can then be recycled for further use in the process, particularly as a pre-wash liquid for the particles.
Description
SPECIFICATION
This invention is in the field of separating oily and fatty materials from solid particles and has particular application to the separation of such material from mill scale. In general, the proces~ consi~ts in subjecting the solid particles to mechan.ical attrition, usually by gr~ndingr and then carrying out at least one froth flotation process on the part~cles to recover cleaned ~olid particles and to recover a clarified wash liquid which can be reu~ed in the process, As mill scale comes from the rolling mills, it is usually contaminated with oily or fatty substances. This requires that the mi].1 scale be washed in a washing solution, separated, and dried be~ore it can be used for commercial purposes, A method ~or cleaning mill scale has been d~scribed in German Patent No, 25 32 68g. In this patent, there is a de~cription of a process wherein mill scale is mixed with 10 to 20 weight percent of a solvent to distribute the f~tty material in the mixture. This mixture is continuously added to a sQlvent bath and is distributed therein. The mill scale is slcwly conveyed out of the solvent bath upon mixing of the scale with an oil-free solvent in countercurrent contact. During the further processing; the solvent is caused to drip from the mill scale and is expelled by heating. The mill scale is thereupon dried. The fat laden solvent is reclaimed by means of distillation. After condensation; ~he fat-free and oil-free solvent is added to the fat containing mill scale and is preferably heated to 40 to 45C.
The apparatus used for carrying out the known method CollSiSts of a driven, horizorltally disposed double shaft mixer prov;ded with a solvent introduction means which is connected to a weighing clevice~ Its output includes a discharge funnel whose openin~ extends into a sedimentation ~ank provided with a solvent bath in which there i8 disposed one end of a screw conveyor conveying upwardly at an oblique angle. A solvent introduction means is provided above the srrew conveyor. The feed enld of spiral vibrating conveyors is disposed at the dischaFge! end of the screw conveyorO A
sedimentation tank having a screw conveyor, a dewatering sieve, and a draining silo are also connected to the upper discharge of the spiral vibrating conveyors. The entire installation is made gas-tight from the ambient atmosphere by means of a housing, and contains a distillation and condensation means for solvent recovery. Fluorinated hydrocarbons~ particularly fluorotrichloromethane or similar organic materials, which ar~ usually poisonous, are employed as solvents.
The method and apparatus of the prior art are extremely complicated. In particulae~ there is a high energy consumption required by the necessity to expel the solvent~ to distill the solvent, as well as for heating the mill scaleO Furthermore, it is necessary to provide a low leakage conduit arrangement, and gas-tight shielding of the overall installation from the ambient atmosphere to avoid losses of solvent so as not to pollute the atmosphere.
The present invention provides an improved process for separating oily and atty materials from solid particles ~uch as mill scale by means of a simple washiny process using an aqueous wash liquor so that a substantial amount of thermal energy is not required.
In the present invention, the mill scale is subjected to a contro].led solid state mechanical load, as by grinding, and then i5 washed in one or more froth flotation stages. The cleaned mill scale is separated f rom the wash liquid and is then dried to eliminate water. The e~fluent liquid d.ischarged from the 10tation cells is subsequently freed of oily and fatty materials together with the wash li~uid arising after the flotation~ and is then returned to the process as a washing liquid.
It has been surprisingly found that a controlled mechanical attrition such as a relatively mild grinding operation is particularl~ suited for conditioning the mill scale for the subsequent wash treatments.
The wash;ng fluicl may consist of aqueous solutions of known detergents which may be anionic, cationic or non-ionic~ Particularly preferred are detergents such a~ aryl alkyl sulfonates, fatty acid condensation products, alk~l polyglycol ethers and the like.
In the preferred form of the present invention9 the mechanical attrition is achieved by grindin~ for a time interval of approximately 2 to 5 minutesO With this type o~
controlled grinding, the mean grain size of the mill scale particles is only slightly reduced, for example, by approximately 4% to 6%~
Presumably, t~e adhesive forces between the mill scale and the oil or fat materials are reduced as a result of the controlled mechanical attrition, and as a result, the cleaning efect of the wash liquid is enhanced.
It is particularly preEerred to conduct the grinding in wash water, preferably recyled wash water, so as to carry out a pre-rinsing of the scale. Such a wet grinding treatment prnmotes Lnterfacial reactions in the capillary range and produces an activation of the mill scale particles for the succeeding wash processes~
AEter pretreatment, the mill scale is subjected to a more complete washing operation in a froth flotation process. Such flotation ~rocesses are known and widely used in the coal and ore processing industries. As a general ruler it is suficient to subject the mill ~cale to be cleaned to a two-stage floltation process~
The above described separation process can be used not only for the separation of mill scale containing oil or fatty materials, but it is also suitable for the separation of petroleum oils from oil ~earing minerals such as sands and rock. In this adaptation o~ the process, it is imp~rtant that the rock or sand which appears in coarse pieces be pre-comminuted beEore such materials are introduced into the ori~inal grinding stage.
~he apparatus for carrying out the invention is relatively ~imple and not particularly expensive. The apparatus usually consists of a grinder~ a flotation machine following the grinder, a solids separator following the flotation machinesJ and a dewatering machine following the latter.
In order to provide a continuous cleaning operation, the grinder is preceded by a delivery station for the mill scale to be cleaned which introduces the mill scale in controlled amounts. The grinder can consist of a rotary drum mill ~ontaining loose grinding bodies such as grinding balls. Its floor i5 suitable for use as a wash container for pre-rinsing the mill scale and is provided with a return conduit for the wash liquid which discharges into the grinder~ The principal washing of the mill scale or the slurry containing the scale takes place in a standard flotation machine having a pluralit~ of Elotatlon cells which have a common over~low channel. The oil or fatty materials which have been washed off together with floated mill scale particles and entrained wash liquor appear in the overflow channel. In order to process this mixture further and to separate the components from one another, the overflow channel at the flotation machine can be connected to a further flotation apparatus whose overflow at the output side discharges into a three element separator. This further flotation apparatus may consist o two flotation cells connected in series ln such a manner that the overflow channel of the first cell discharges into the input of the lS second cell~ and the overflow channel of the latter is connected to the three element separator. Preferably, the underflow of the last cell in the series is returned into the intake of the first cell so that a continuous circulation occurs.
An extensive separation of oil and fat from the oil-solids-water mixture floated out in the principal washing station is accomplished in the further flotation apparatus so that the wash liquid with its solids component can be reintroduced into the washing process for the mill scale slurry to be cleaned. It is advisable to provide a conditioning container between the grinding apparatus and the flotation machine for introducing the required flotation reagents-clnd the detergents.
The flotation machine for the principal wash of the mill scale can be designed as a two-stage operation in which the irst multi-cell flotation stage is followed by an ., ..~
~6~ 2 additional flotation cell whose overflow channel ha~ a return conduit for washing li~uid leading into the conditioning container. The return conduit for washing liquid from the further flotation apparatus is arranged to discharge into the conditioniny container~
In a particularly preferred embodiment of the present invention, the solids separator employed is a magneti~ separator.
The apparatus of the present invention is also well suited for recovering petroleum oils from ole.iferous roclc provided that there is a comminution of the mineral materials prior to grinding~ For purposes of comminution, a jaw crusher, a cone crusher, or a breakdown mill can be connected to the grinderO
The single Figure of the drawing consists of a flow chart illustrating a preferred embodiment of the present invent;on as ît is applied to the cleaning of mill ~cale.
In the ~ingle Figure of the drawings, the 20 ~I principal elements consist of a grinder 1, a flotation machine consistin~ of two sections 2 and 3, a solids separator 4 and a dewatering machine 5.
Mill scale derived, for example, from a rolling mill or from a continuous casting installation usually occurs as a damp sludge contaminatea with oil or fatty materials~ Such sludge i~ kept in a feed sta~ion 6 and is suppliad in metered amounts to a grinder 1 through a conduit 8 by means of a screw discharge conveyor 7, The grinder 1, for example, may consist of a rotary drum mill containing grinding ballsO The drum of the grinder 1 îs rotatable by means of a casing drive ~ and is employed as a wash container for the pre-rinsing oP the mill scale. The output of the grinder 1 is connected through a conduit 10 to an intermediate container 11 which discharges through a conduit 12 to a conditioning container 13 in which an agitator 14 is dipsosed. A conduit 15 discharges the material from the container 13 into a first section 2 of the flotation machine for the main washing of the mill scale~ The flotation section 2 consists of a plurality of individua~ flotation cells 16, each equipped with an agitator 17~ All of the 1~ cells 16 share a common overflow channel 18. In the conventional manner, air i5 introduced into the cell 16 through sultable means not shown on the drawing. A froth is produced by the fine bubble airstream through the action of the agitators 17~ A conduit 19 delivers the residual material to a second portion 3 of the flotation apparatus.
An overflow channel 20 discharges through a return conduit 21 into the conditioning container 1~ A conduit 22 leads from the underflow of the flotation cell 3 into a solids separator 4 which is preferably a magnetic separator. The separated, concentrated mill scale slurry is supplied through a conduit 23 to a dewatering machine 5 for further elimination of water to produce a dewatered material which is deposited onto a conveyor belt 24. The discharge from the solids separator 4 through conduit 25 and the discharge from the dewatering machine 5 through a conduit 26 are combined at junction 27 and consists primarily of a wash liquid which contains only a slight amount of extremely fine solids co~ponents. Thi,s llquid is passed to a clarifying means 28 such as a ~affle plate thickener having a discharge screw 2g to discharge a concentrated sludge through a conduit 30 into a sedimentation tank (not ;llustrated) or ~L~t~
the like. The li~uid overflow is taken through a discharge 31 through a conduit 32 to an intermediate storage station 33 ~if necessary) and finally throuyh a recycle conduit 34 back into the grinder 1.
A conduit 35 connects the overflow channel of the principal portion 2 of the flotation mach.ine to a storage container 36 from which it is int~oduced into another froth flotation device consisting of a first flotation cell 37 which is connected in series with a secona ~lotati~n cell 38 by means of a conduit 40. Underflow from the second cell 38 i~ taken through a conduit 43 and is returned by means of conduit 44 back into the storage container 36. Thus, there is a continuous closed circulat1on path provide~ between the two cell~.
The agitators for generating a fine bubble airstream are identified at reference numerals 41 and 42 respectively. An overflow channel 45 of the second cell 38 is connected through a conduit 46 to a three element separator 47 which may be a tubular bowl centrifuge capable of separating a solids product from two li~uid products ~f different density. The separator 47 has a dlscharge 4R for o;l, a discharge 49 for solids, and a discharge 50 for the washing solution. ~he discharge line 50 is directed into the inlet container 33 which returns washing liquid through the conduit 34 into the grinder 1.
Damp mill scale from the feed station 6 is subjected to c~ntrolled mechanical at~rition in the drum mill under the influence of the grinding balls whereby the adhesive forces between the oil, the fatty material, and the mill scale particles are reduced. A grinding time vf approximately 2 to 5 minutes generally suffices to achieve ., , .~
the corlditioning of the mill scale for the subsequent washing process. Only a slight reduction of the mean grain size of the mill scale particles occurs, or example, approximately 4% to 6%. Consequently, the mill scale particles which generally exhibit fissures at their surfaces are essentially only smoothed by the grinding operation. In the grinder 1, the mill scale is pre-rinsed in the cleansed washing liquid returned by ~leans of the conduit 34 50 that a preconditioned slurry passes through the concluits 10, 12 into the conditioning container 13. This slurry is then introfluced into the first froth flotation stage. The froth flotation is carried out in a manner known from other flotation processes, for example, from ore or coal processing, in that the slurry i5 rendered highly alkaline by the addition, for example, of caustic soda through the conduit 52 and further, frothing agents are added. The required amount of washing detergents is added to the conditioning container 13.
A substantial part of the oil and ~atty components are floated to the overflow channel 18 and the principal portion 2 of the ~lotation machine so that a slurry consisting of wash liquid and largely de-oiled mill scale flows from the conduit 19 inko the additional flotation cell 3 o the flotation machine. A dispersion consisting of wash liquid, floated mill scale particles and residual oil appears at the overflow channel 20 of the cell 3~ the dispersion being returned through the conduit 21 into the conditioning container 13 ahead of the flotation cells.
This cireulation produces a repeated washing of the materials and repeated separation. The de-oiled and de-fatted slurry in conduit 22 at the underflow of the cell 3 proceeds into the magnetic separator 4 where the solids are separated~ are subse~uently dried, and can be su~plied to the conveyor belt 24. Washing liquid arising from the solids separation and the dewatering process is returned to the process as a clarified liquid ari~ing from treatmen~ in the baffle plate thickener 28.
The mill scal.e on the conveyor belt 24 is a shapeable material whose moisture content can be adjusted for subsequent processing such as pelletizing. This cleaned mill scale i~ largely free from oil and fatty components.
A foamy dispersion consisting predominantly of oil, washing solution and floated, fine solid particles collects in the overflvw channel 18 of the principal section
This invention is in the field of separating oily and fatty materials from solid particles and has particular application to the separation of such material from mill scale. In general, the proces~ consi~ts in subjecting the solid particles to mechan.ical attrition, usually by gr~ndingr and then carrying out at least one froth flotation process on the part~cles to recover cleaned ~olid particles and to recover a clarified wash liquid which can be reu~ed in the process, As mill scale comes from the rolling mills, it is usually contaminated with oily or fatty substances. This requires that the mi].1 scale be washed in a washing solution, separated, and dried be~ore it can be used for commercial purposes, A method ~or cleaning mill scale has been d~scribed in German Patent No, 25 32 68g. In this patent, there is a de~cription of a process wherein mill scale is mixed with 10 to 20 weight percent of a solvent to distribute the f~tty material in the mixture. This mixture is continuously added to a sQlvent bath and is distributed therein. The mill scale is slcwly conveyed out of the solvent bath upon mixing of the scale with an oil-free solvent in countercurrent contact. During the further processing; the solvent is caused to drip from the mill scale and is expelled by heating. The mill scale is thereupon dried. The fat laden solvent is reclaimed by means of distillation. After condensation; ~he fat-free and oil-free solvent is added to the fat containing mill scale and is preferably heated to 40 to 45C.
The apparatus used for carrying out the known method CollSiSts of a driven, horizorltally disposed double shaft mixer prov;ded with a solvent introduction means which is connected to a weighing clevice~ Its output includes a discharge funnel whose openin~ extends into a sedimentation ~ank provided with a solvent bath in which there i8 disposed one end of a screw conveyor conveying upwardly at an oblique angle. A solvent introduction means is provided above the srrew conveyor. The feed enld of spiral vibrating conveyors is disposed at the dischaFge! end of the screw conveyorO A
sedimentation tank having a screw conveyor, a dewatering sieve, and a draining silo are also connected to the upper discharge of the spiral vibrating conveyors. The entire installation is made gas-tight from the ambient atmosphere by means of a housing, and contains a distillation and condensation means for solvent recovery. Fluorinated hydrocarbons~ particularly fluorotrichloromethane or similar organic materials, which ar~ usually poisonous, are employed as solvents.
The method and apparatus of the prior art are extremely complicated. In particulae~ there is a high energy consumption required by the necessity to expel the solvent~ to distill the solvent, as well as for heating the mill scaleO Furthermore, it is necessary to provide a low leakage conduit arrangement, and gas-tight shielding of the overall installation from the ambient atmosphere to avoid losses of solvent so as not to pollute the atmosphere.
The present invention provides an improved process for separating oily and atty materials from solid particles ~uch as mill scale by means of a simple washiny process using an aqueous wash liquor so that a substantial amount of thermal energy is not required.
In the present invention, the mill scale is subjected to a contro].led solid state mechanical load, as by grinding, and then i5 washed in one or more froth flotation stages. The cleaned mill scale is separated f rom the wash liquid and is then dried to eliminate water. The e~fluent liquid d.ischarged from the 10tation cells is subsequently freed of oily and fatty materials together with the wash li~uid arising after the flotation~ and is then returned to the process as a washing liquid.
It has been surprisingly found that a controlled mechanical attrition such as a relatively mild grinding operation is particularl~ suited for conditioning the mill scale for the subsequent wash treatments.
The wash;ng fluicl may consist of aqueous solutions of known detergents which may be anionic, cationic or non-ionic~ Particularly preferred are detergents such a~ aryl alkyl sulfonates, fatty acid condensation products, alk~l polyglycol ethers and the like.
In the preferred form of the present invention9 the mechanical attrition is achieved by grindin~ for a time interval of approximately 2 to 5 minutesO With this type o~
controlled grinding, the mean grain size of the mill scale particles is only slightly reduced, for example, by approximately 4% to 6%~
Presumably, t~e adhesive forces between the mill scale and the oil or fat materials are reduced as a result of the controlled mechanical attrition, and as a result, the cleaning efect of the wash liquid is enhanced.
It is particularly preEerred to conduct the grinding in wash water, preferably recyled wash water, so as to carry out a pre-rinsing of the scale. Such a wet grinding treatment prnmotes Lnterfacial reactions in the capillary range and produces an activation of the mill scale particles for the succeeding wash processes~
AEter pretreatment, the mill scale is subjected to a more complete washing operation in a froth flotation process. Such flotation ~rocesses are known and widely used in the coal and ore processing industries. As a general ruler it is suficient to subject the mill ~cale to be cleaned to a two-stage floltation process~
The above described separation process can be used not only for the separation of mill scale containing oil or fatty materials, but it is also suitable for the separation of petroleum oils from oil ~earing minerals such as sands and rock. In this adaptation o~ the process, it is imp~rtant that the rock or sand which appears in coarse pieces be pre-comminuted beEore such materials are introduced into the ori~inal grinding stage.
~he apparatus for carrying out the invention is relatively ~imple and not particularly expensive. The apparatus usually consists of a grinder~ a flotation machine following the grinder, a solids separator following the flotation machinesJ and a dewatering machine following the latter.
In order to provide a continuous cleaning operation, the grinder is preceded by a delivery station for the mill scale to be cleaned which introduces the mill scale in controlled amounts. The grinder can consist of a rotary drum mill ~ontaining loose grinding bodies such as grinding balls. Its floor i5 suitable for use as a wash container for pre-rinsing the mill scale and is provided with a return conduit for the wash liquid which discharges into the grinder~ The principal washing of the mill scale or the slurry containing the scale takes place in a standard flotation machine having a pluralit~ of Elotatlon cells which have a common over~low channel. The oil or fatty materials which have been washed off together with floated mill scale particles and entrained wash liquor appear in the overflow channel. In order to process this mixture further and to separate the components from one another, the overflow channel at the flotation machine can be connected to a further flotation apparatus whose overflow at the output side discharges into a three element separator. This further flotation apparatus may consist o two flotation cells connected in series ln such a manner that the overflow channel of the first cell discharges into the input of the lS second cell~ and the overflow channel of the latter is connected to the three element separator. Preferably, the underflow of the last cell in the series is returned into the intake of the first cell so that a continuous circulation occurs.
An extensive separation of oil and fat from the oil-solids-water mixture floated out in the principal washing station is accomplished in the further flotation apparatus so that the wash liquid with its solids component can be reintroduced into the washing process for the mill scale slurry to be cleaned. It is advisable to provide a conditioning container between the grinding apparatus and the flotation machine for introducing the required flotation reagents-clnd the detergents.
The flotation machine for the principal wash of the mill scale can be designed as a two-stage operation in which the irst multi-cell flotation stage is followed by an ., ..~
~6~ 2 additional flotation cell whose overflow channel ha~ a return conduit for washing li~uid leading into the conditioning container. The return conduit for washing liquid from the further flotation apparatus is arranged to discharge into the conditioniny container~
In a particularly preferred embodiment of the present invention, the solids separator employed is a magneti~ separator.
The apparatus of the present invention is also well suited for recovering petroleum oils from ole.iferous roclc provided that there is a comminution of the mineral materials prior to grinding~ For purposes of comminution, a jaw crusher, a cone crusher, or a breakdown mill can be connected to the grinderO
The single Figure of the drawing consists of a flow chart illustrating a preferred embodiment of the present invent;on as ît is applied to the cleaning of mill ~cale.
In the ~ingle Figure of the drawings, the 20 ~I principal elements consist of a grinder 1, a flotation machine consistin~ of two sections 2 and 3, a solids separator 4 and a dewatering machine 5.
Mill scale derived, for example, from a rolling mill or from a continuous casting installation usually occurs as a damp sludge contaminatea with oil or fatty materials~ Such sludge i~ kept in a feed sta~ion 6 and is suppliad in metered amounts to a grinder 1 through a conduit 8 by means of a screw discharge conveyor 7, The grinder 1, for example, may consist of a rotary drum mill containing grinding ballsO The drum of the grinder 1 îs rotatable by means of a casing drive ~ and is employed as a wash container for the pre-rinsing oP the mill scale. The output of the grinder 1 is connected through a conduit 10 to an intermediate container 11 which discharges through a conduit 12 to a conditioning container 13 in which an agitator 14 is dipsosed. A conduit 15 discharges the material from the container 13 into a first section 2 of the flotation machine for the main washing of the mill scale~ The flotation section 2 consists of a plurality of individua~ flotation cells 16, each equipped with an agitator 17~ All of the 1~ cells 16 share a common overflow channel 18. In the conventional manner, air i5 introduced into the cell 16 through sultable means not shown on the drawing. A froth is produced by the fine bubble airstream through the action of the agitators 17~ A conduit 19 delivers the residual material to a second portion 3 of the flotation apparatus.
An overflow channel 20 discharges through a return conduit 21 into the conditioning container 1~ A conduit 22 leads from the underflow of the flotation cell 3 into a solids separator 4 which is preferably a magnetic separator. The separated, concentrated mill scale slurry is supplied through a conduit 23 to a dewatering machine 5 for further elimination of water to produce a dewatered material which is deposited onto a conveyor belt 24. The discharge from the solids separator 4 through conduit 25 and the discharge from the dewatering machine 5 through a conduit 26 are combined at junction 27 and consists primarily of a wash liquid which contains only a slight amount of extremely fine solids co~ponents. Thi,s llquid is passed to a clarifying means 28 such as a ~affle plate thickener having a discharge screw 2g to discharge a concentrated sludge through a conduit 30 into a sedimentation tank (not ;llustrated) or ~L~t~
the like. The li~uid overflow is taken through a discharge 31 through a conduit 32 to an intermediate storage station 33 ~if necessary) and finally throuyh a recycle conduit 34 back into the grinder 1.
A conduit 35 connects the overflow channel of the principal portion 2 of the flotation mach.ine to a storage container 36 from which it is int~oduced into another froth flotation device consisting of a first flotation cell 37 which is connected in series with a secona ~lotati~n cell 38 by means of a conduit 40. Underflow from the second cell 38 i~ taken through a conduit 43 and is returned by means of conduit 44 back into the storage container 36. Thus, there is a continuous closed circulat1on path provide~ between the two cell~.
The agitators for generating a fine bubble airstream are identified at reference numerals 41 and 42 respectively. An overflow channel 45 of the second cell 38 is connected through a conduit 46 to a three element separator 47 which may be a tubular bowl centrifuge capable of separating a solids product from two li~uid products ~f different density. The separator 47 has a dlscharge 4R for o;l, a discharge 49 for solids, and a discharge 50 for the washing solution. ~he discharge line 50 is directed into the inlet container 33 which returns washing liquid through the conduit 34 into the grinder 1.
Damp mill scale from the feed station 6 is subjected to c~ntrolled mechanical at~rition in the drum mill under the influence of the grinding balls whereby the adhesive forces between the oil, the fatty material, and the mill scale particles are reduced. A grinding time vf approximately 2 to 5 minutes generally suffices to achieve ., , .~
the corlditioning of the mill scale for the subsequent washing process. Only a slight reduction of the mean grain size of the mill scale particles occurs, or example, approximately 4% to 6%. Consequently, the mill scale particles which generally exhibit fissures at their surfaces are essentially only smoothed by the grinding operation. In the grinder 1, the mill scale is pre-rinsed in the cleansed washing liquid returned by ~leans of the conduit 34 50 that a preconditioned slurry passes through the concluits 10, 12 into the conditioning container 13. This slurry is then introfluced into the first froth flotation stage. The froth flotation is carried out in a manner known from other flotation processes, for example, from ore or coal processing, in that the slurry i5 rendered highly alkaline by the addition, for example, of caustic soda through the conduit 52 and further, frothing agents are added. The required amount of washing detergents is added to the conditioning container 13.
A substantial part of the oil and ~atty components are floated to the overflow channel 18 and the principal portion 2 of the ~lotation machine so that a slurry consisting of wash liquid and largely de-oiled mill scale flows from the conduit 19 inko the additional flotation cell 3 o the flotation machine. A dispersion consisting of wash liquid, floated mill scale particles and residual oil appears at the overflow channel 20 of the cell 3~ the dispersion being returned through the conduit 21 into the conditioning container 13 ahead of the flotation cells.
This cireulation produces a repeated washing of the materials and repeated separation. The de-oiled and de-fatted slurry in conduit 22 at the underflow of the cell 3 proceeds into the magnetic separator 4 where the solids are separated~ are subse~uently dried, and can be su~plied to the conveyor belt 24. Washing liquid arising from the solids separation and the dewatering process is returned to the process as a clarified liquid ari~ing from treatmen~ in the baffle plate thickener 28.
The mill scal.e on the conveyor belt 24 is a shapeable material whose moisture content can be adjusted for subsequent processing such as pelletizing. This cleaned mill scale i~ largely free from oil and fatty components.
A foamy dispersion consisting predominantly of oil, washing solution and floated, fine solid particles collects in the overflvw channel 18 of the principal section
2 oE the ~lotation machine. 1~his slurry is floated in the cells 37, 38 in series so that a liquid oil product containing only small amounts o wash liquid and solids appears in the overflow channel 45 at the output side. The oil and washing liquid are separated from the ~olids in the three element separator 47~ A wash liquid which is largely oil free appears at the underflow of the flotation cell 37, the wash liquid containing predominantly the solid components from the foamy dispersion in the overflow channel 18 from the principal portion ~ of the flotation machine.
This wash liquid with its solids can be returned into the conditioning container 13 through the conduit 51.
In tests carried out, it was found that mill scale contaminated with oil and fat to the extent of 3 to 5 weight percent could be cleaned to reduce the oil and fat content below 0.3 weight percent. Such c].eane~ mil~ scale can be used~ for example, in sintering processes for fine ores since there i~ no danger that the oil will be combustibl.e as C~
in the case of uncleaned mill ~cale,.
For the production of petroleum from oleiferous rock containing the same, it was found that by crushing the rock to a grain size of less than ~0 mm and then recrushing the same to a grain size of less than 5 mm, followed by grinding to a grain size of less than 1 mm, further processing of such rock could proceed in accordance with the treatment described for mill scale. The petroleum to be recovered flows through the conduit 46 with only a small amount oE solids and wash li.quor, and is discharged at the discharge 48 of the three element separator 47.
It should be evident that various modifications can be made to the described embodiments without departing from the scope of the present invention.
This wash liquid with its solids can be returned into the conditioning container 13 through the conduit 51.
In tests carried out, it was found that mill scale contaminated with oil and fat to the extent of 3 to 5 weight percent could be cleaned to reduce the oil and fat content below 0.3 weight percent. Such c].eane~ mil~ scale can be used~ for example, in sintering processes for fine ores since there i~ no danger that the oil will be combustibl.e as C~
in the case of uncleaned mill ~cale,.
For the production of petroleum from oleiferous rock containing the same, it was found that by crushing the rock to a grain size of less than ~0 mm and then recrushing the same to a grain size of less than 5 mm, followed by grinding to a grain size of less than 1 mm, further processing of such rock could proceed in accordance with the treatment described for mill scale. The petroleum to be recovered flows through the conduit 46 with only a small amount oE solids and wash li.quor, and is discharged at the discharge 48 of the three element separator 47.
It should be evident that various modifications can be made to the described embodiments without departing from the scope of the present invention.
Claims (15)
1. A process for separating oily and fatty materials from solid particles to which they are attached comprising subjecting the solid particles to mechanical attrition in the presence of a wash liquid, subjecting the resulting particles to at least one froth flotation process with a washing liquid, separating the cleaned solid particles form said flotation process from the washing liquid, separating oily and fatty materials from the effluent of said froth flotation process to produce a clarified wash liquid, and recycling the clarified wash liquid to the mechanical attrition stage to constitute at least part of said wash liquid.
2. A process according to claim 1 in which said washing liquid comprises an aqueous detergent solution.
3. A process according to claim 1 in which said mechanical attrition consists of grinding.
4. A process according to claim 1 in which the solid particles are mill scale.
5. A process according to claim 4 which includes the step of pre-washing the mill scale with recycles clarified wash liquid while subjecting the mill scale to said mechanical attrition.
6. A process according to claim 1 in which the mean grain size of said solid particles is only slightly reduced by said mechanical attrition.
7. A process according the claim 6 in which said mean grain size is reduced by about 4 to 6%.
8. An apparatus for cleaning mill scale to remove oily and fatty materials therefrom comprising a grinder, means for introducing mill scale particles into said grinder, a froth flotation device receiving the mill scale particles from said grinder, a solids separator receiving solids separated out in said froth flotation device, and dewatering means receiving the solids recovered in said solids separator.
9. An apparatus according to claim 8 in which said grinder includes a rotating drum containing grinding balls.
10. An apparatus according to claim 8 which includes means for introducing a washing liquid into said grinder.
11. An apparatus according to claim 8 which includes means for recycling a washing liquid recovered from said froth flotation device back into said grinder.
12. An apparatus according to claim 8 which includes a three element centrifugal separator, and means for introducing the effluent from said froth flotation device into said centrifugal separator.
13. An apparatus according to claim 12 in which said froth flotation device consists of at least two stages, and an additional froth flotation device receiving the effluent from said two stages, and containing at least two stages in series, said additional froth flotation device including means for returning the discharge from the last stage to the intake of the first stage.
14. An apparatus according to claim 8 which includes means for injecting a washing liquid into the material being treated between said grinder and said froth flotation device.
15. An apparatus according to claim 8 in which said solids separator comprises a magnetic separator.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE3147521 | 1981-12-01 | ||
| DEP3147521.3 | 1981-12-01 | ||
| DEP3223011.7 | 1982-06-19 | ||
| DE19823223011 DE3223011A1 (en) | 1981-12-01 | 1982-06-19 | METHOD AND PLANT FOR CLEANING WITH FATTY SUBSTANCES, ESPECIALLY OIL, DIRTED ROLLER TUNER AND FOR RECOVERING PETROLEUM FROM OIL-CONTAINING MINERALS |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1196012A true CA1196012A (en) | 1985-10-29 |
Family
ID=25797687
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000416647A Expired CA1196012A (en) | 1981-12-01 | 1982-11-30 | Method and apparatus for separating oily and fatty materials from solid particles |
Country Status (7)
| Country | Link |
|---|---|
| EP (1) | EP0080589B1 (en) |
| AU (1) | AU9069882A (en) |
| CA (1) | CA1196012A (en) |
| DE (2) | DE3223011A1 (en) |
| ES (1) | ES8307535A1 (en) |
| MX (1) | MX160540A (en) |
| NO (1) | NO159904C (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2020046370A1 (en) * | 2018-08-31 | 2020-03-05 | Gt Of Ohio, Ltd | Method and apparatus for continuous magnetic filtration of ferrous mill scale from liquid solutions |
Families Citing this family (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1985001069A1 (en) * | 1983-09-08 | 1985-03-14 | Georg Von Bormann | Process, plant and/or device for preparing oil-coated scales or similar materials |
| DE3544240A1 (en) * | 1985-12-14 | 1987-06-19 | Metallgesellschaft Ag | Method for processing fragmented wastes contaminated with fats or oils |
| US4783263A (en) * | 1986-06-17 | 1988-11-08 | Trost Paul B | Detoxification process |
| DE3827831A1 (en) * | 1988-08-17 | 1990-02-22 | Thyssen Industrie | METHOD AND SYSTEM FOR THE TREATMENT OF WASTEWATER, IN PARTICULAR FROM THE FLUE GAS DESULFURATION |
| US5047083A (en) * | 1989-06-15 | 1991-09-10 | Nalco Chemical Company | Process for de-oiling mill scale |
| US5125966A (en) * | 1990-12-20 | 1992-06-30 | Nalco Chemical Company | Process for de-oiling mill sludge |
| DE4115819A1 (en) * | 1991-05-15 | 1992-11-19 | Schloemann Siemag Ag | METHOD FOR TREATMENT OF COOLING AND / OR LUBRICANTS USED IN ROLLING MILLS, AND A TREATMENT SYSTEM FOR THIS |
| DE4115920C2 (en) * | 1991-05-16 | 1993-12-16 | Thyssen Industrie | Method and device for cleaning granular materials from fatty substances, in particular oil |
| DE4136990C2 (en) * | 1991-11-11 | 2002-12-05 | Ald Vacuum Techn Ag | Process for degreasing and cleaning goods with greasy and / or oily substances |
| DE4320935C1 (en) * | 1993-06-24 | 1994-12-22 | Salzgitter Anlagenbau | Processing assembly to process for sludge and sand containing oil and grease |
| DE19614689C2 (en) * | 1996-04-13 | 1999-11-04 | Maximilian Bauknecht | Multi-purpose system for the thermal treatment of starting substances |
| DE29710848U1 (en) * | 1997-06-20 | 1997-08-28 | Preussag Wassertechnik GmbH, 28359 Bremen | Sinter well system |
| EP2113490B1 (en) * | 2008-04-28 | 2012-09-12 | Edgar Bonnaire | Method and device for mechanical separation of secondary raw materials from sludge containing iron |
| GB2529874A (en) * | 2014-09-05 | 2016-03-09 | Darlow Lloyd & Sons Ltd | Reuse of by-products from metallurgical processes, processing of waste materials and products thereof |
| DE102016112087A1 (en) * | 2016-07-01 | 2018-01-04 | EnBW Energie Baden-Württemberg AG | A scale sludge treatment apparatus and method of operating a scale sludge treatment apparatus |
| IL273181B (en) * | 2020-03-09 | 2021-08-31 | Dmitry Rumnitsky | System for deoiling mill scale and method of implementing the same |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3997359A (en) * | 1972-11-07 | 1976-12-14 | Joseph Daniel Dankoff | Reclamation of components from grinding swarf |
| DE2610803A1 (en) * | 1976-03-15 | 1977-09-22 | Jackson E L | Cleaner for used abrasive sand - has particles graded for size before cyclonic separation of sand in water suspension |
| US4097306A (en) * | 1976-08-09 | 1978-06-27 | Prab Conveyors, Inc. | Method of cleaning swarf |
| DE3043220C2 (en) * | 1980-11-15 | 1982-10-07 | Schauenburg Maschinen- und Anlagen-Bau GmbH, 4330 Mülheim | Method and system for reducing the oil content of oil-contaminated rolled sinter and the like. |
| DE3146809C1 (en) * | 1980-11-15 | 1982-11-04 | Schauenburg Maschinen- und Anlagen-Bau GmbH, 4330 Mülheim | Process and equipment for reducing the oil content of oil-contaminated mill scale |
| DE3120463C1 (en) * | 1980-11-15 | 1982-10-28 | Schauenburg Maschinen- und Anlagen-Bau GmbH, 4330 Mülheim | Process and installation for reducing the oil content of oil-contaminated rolling sinter, mill scale and the like |
-
1982
- 1982-06-19 DE DE19823223011 patent/DE3223011A1/en not_active Withdrawn
- 1982-10-13 EP EP19820109464 patent/EP0080589B1/en not_active Expired
- 1982-10-13 DE DE8282109464T patent/DE3272600D1/en not_active Expired
- 1982-11-11 NO NO823769A patent/NO159904C/en unknown
- 1982-11-18 AU AU90698/82A patent/AU9069882A/en not_active Abandoned
- 1982-11-25 MX MX19532882A patent/MX160540A/en unknown
- 1982-11-30 ES ES517829A patent/ES8307535A1/en not_active Expired
- 1982-11-30 CA CA000416647A patent/CA1196012A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2020046370A1 (en) * | 2018-08-31 | 2020-03-05 | Gt Of Ohio, Ltd | Method and apparatus for continuous magnetic filtration of ferrous mill scale from liquid solutions |
Also Published As
| Publication number | Publication date |
|---|---|
| NO823769L (en) | 1983-06-02 |
| DE3272600D1 (en) | 1986-09-18 |
| ES517829A0 (en) | 1983-08-16 |
| EP0080589A1 (en) | 1983-06-08 |
| EP0080589B1 (en) | 1986-08-13 |
| AU9069882A (en) | 1983-06-09 |
| ES8307535A1 (en) | 1983-08-16 |
| DE3223011A1 (en) | 1983-07-14 |
| NO159904B (en) | 1988-11-14 |
| MX160540A (en) | 1990-03-20 |
| NO159904C (en) | 1989-02-22 |
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