EP0246105B1 - Feinkohlegewinnung - Google Patents

Feinkohlegewinnung Download PDF

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Publication number
EP0246105B1
EP0246105B1 EP87304307A EP87304307A EP0246105B1 EP 0246105 B1 EP0246105 B1 EP 0246105B1 EP 87304307 A EP87304307 A EP 87304307A EP 87304307 A EP87304307 A EP 87304307A EP 0246105 B1 EP0246105 B1 EP 0246105B1
Authority
EP
European Patent Office
Prior art keywords
slurry
weight
coal
froth flotation
hydrophobic
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 - Lifetime
Application number
EP87304307A
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English (en)
French (fr)
Other versions
EP0246105A2 (de
EP0246105A3 (en
Inventor
Gerald Frederick Brookes
Lynne Spencer
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fospur Ltd
Original Assignee
Fospur Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Fospur Ltd filed Critical Fospur Ltd
Publication of EP0246105A2 publication Critical patent/EP0246105A2/de
Publication of EP0246105A3 publication Critical patent/EP0246105A3/en
Application granted granted Critical
Publication of EP0246105B1 publication Critical patent/EP0246105B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03D—FLOTATION; DIFFERENTIAL SEDIMENTATION
    • B03D3/00—Differential sedimentation
    • B03D3/06—Flocculation
    • 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
    • B03D1/001—Flotation agents
    • B03D1/004—Organic compounds
    • B03D1/006—Hydrocarbons
    • 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
    • B03D1/001—Flotation agents
    • B03D1/004—Organic compounds
    • B03D1/016—Macromolecular compounds
    • 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
    • B03D1/02—Froth-flotation processes
    • 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
    • B03D2201/00—Specified effects produced by the flotation agents
    • B03D2201/04—Frothers
    • 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
    • B03D2203/00—Specified materials treated by the flotation agents; Specified applications
    • B03D2203/02—Ores
    • B03D2203/04—Non-sulfide ores
    • B03D2203/08—Coal ores, fly ash or soot
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B3/00—Engines characterised by air compression and subsequent fuel addition
    • F02B3/06—Engines characterised by air compression and subsequent fuel addition with compression ignition

Definitions

  • This invention concerns recovering coal from aqueous slurries of coal fines also containing associated impurities as suspended fine solids and compositions of use in the recovery process.
  • Coal as mined contains a proportion of impurities (hereinafter called 'shale') and, in the case of the fine particles present, separation of the coal from the shale presents considerable problems.
  • 'shale' impurities
  • This fine 'coal' typically has a substantial coal content but also a substantial shale content so it is important to make use of the coal content but also to remove shale from it.
  • Modern coal preparation processes result in the fines (separated from coarser material) being in the form of aqueous slurries.
  • the usual separation technique applied to the aqueous slurry of fines is to pass the slurry through a hydrocyclone and then feed the hydrocyclone underflow to a screen having apertures of about 0.25 mm.
  • the "product" i.e. coal fines with a reduced proportion of shale fines is the matter retained by the screen whilst the hydrocyclone overflow and the matter passing through the screen are discarded.
  • a consequent disadvantage is that the significant proportion of the coal having particle sizes below 0.25 mm is lost.
  • coal fines are selectively agglomerated, with respect to shale fines, by use of an oil "binder" and the coal agglomerates are then separated from the shale fines by a screening or classification process.
  • the process has the disadvantage of requiring a substantial proportion of oil in relation to the solids in the slurry being treated.
  • An aqueous coal slurry is admixed with a surface treating mixture under polymerisation conditions and the resultant surface treated coal is rendered hydrophobic.
  • a method of recovering coal fines from an aqueous slurry also containing shale as suspended fine solids in which the coal fines are rendered hydrophobic the resulting mixture is agitated, gas is introduced into the slurry to form bubbles whereby flocs of coal fines formed are caused to float, and the underlying slurry containing shale is discarded characterised in that the coal fines are rendered hydrophobic by the addition to the slurry of a hydrophobic polyvinylether in a liquid organic carrier.
  • coal fines can be flocculated efficiently by use of hydrophobic polyvinylethers and that the flocculation is highly selective for coal fines in preference to shale fines.
  • flocs of coal fines are formed selectively in preference to flocs of shale fines and a high degree of selectivity can be achieved.
  • the agglomeration of the coal fines into flocs reduces the exposed surface area of the coal and thereby reduces entrainment of shale fines with the coal.
  • the coal fines can be formed into flocs of sufficient strength to survive vigorous agitation of the slurry and by agitation of the slurry the flocs of coal fines can be caused to 'extrude' shale fines and water that may initially have been entrained within the flocs.
  • the method of the invention should be performed as a froth flotation in a froth flotation cell, using, in addition to polyvinylether and carrier, a frother, as used in conventional froth flotation processes.
  • the organic liquid not only acts as a carrier for the polyvinylether but it also acts as a so-called collector in the conventional froth flotation sense.
  • the polyvinylether dosage may be as low as say 0.5 kg/tonne of slurry solids.
  • high yields are obtainable i.e. not only is the method highly selective as between coal fines and shale fines but also a high proportion of the coal fines, particularly those of very low particle sizes (less than about 50 microns) can be recovered.
  • Polyvinylethers have been found to be particularly satisfactory in the case of the more aliphatic coals e.g. steam coals.
  • Gas oil has been found to be a particularly satisfactory carrier for the polyvinylether.
  • examples of other carriers that may be used include diesel oil, and kerosene and other petroleum and coal-based distillates.
  • a co-solvent compatible with the carrier may be used.
  • co-solvents include toluene, xylenes and other aromatic solvents and hexane and other paraffinic solvents. Co-solvents may be particularly useful if the polyvinylether is of high molecular weight.
  • the efficiency of the method is dependent on the dosage rate of the polyvinylether in relation to the solids in the slurry.
  • some recovery of the coal fines may be achieved with a dosage rate as low as for example, 2.45 kg. polyvinylether/tonne of slurry solids but under the same conditions an almost double dosage rate of 4.71 gave far superior results.
  • the optimum dosage rate in any particular case is that just sufficient to cause effective flocculation of substantially all the coal fines. Whilst high selectivity may be retained with lesser rates, only partial recovery of the coal fines is then achievable. Rates higher than the optimum are simply wasteful of the polyvinylether.
  • an additive composition for use in the froth flotation method of the invention comprises 5 - 25% of hydrophobic polyvinylether, 5 - 25% of frother and 50 - 90% of liquid organic carrier, all by weight.
  • the frother may be as in the known froth flotation process, and may be for example methyl isobutyl carbinol or a mixture of polypropylene glycol ethers available under the tradename TEEFROTH G.
  • the composition is preferably used in an amount not greater than 10 kg per tonne of slurry solids, especially 0.5 - 5 kg per tonne.
  • the method of the invention gives rise to a secondary advantage in that the coal flocs formed are more readily filtered than coal fines which have not been flocculated. Moreover, not only can the filtration be carried out more quickly but also it gives rise to a coal residue having the advantage of a lower water content.
  • the method of the invention is applicable to coal/shale slurries of the types that in the past have been subjected to conventional froth flotation processes.
  • the size of the coal and shale particles is usually less than 500 microns and commonly up to 50% by weight of the particles can have sizes less than 50 microns.
  • Process I Three different treatment processes were applied to the slurry.
  • Process I the chosen additive was added to a sample of the slurry in a separating funnel and the mixture stirred at a low speed such that thorough mixing occurred but there was substantially no creation of air bubbles in the slurry.
  • the stirring was then discontinued, solids allowed to sediment out, the sediment separated from the slurry above and both the sediment and the overlying slurry collected, the sediment returned to the funnel, water added and the resultant mixture again stirred slowly, the stirring again discontinued and solids again allowed to sediment out and the sediment separated from the overlying slurry and both collected.
  • the sediment was filtered, dried and weighed (to determine the product yield of the process) and then burnt and reweighed (to determine the ash content of the product).
  • the two portions of collected separated slurry were separately filtered and the residues dried, weighed and burnt (to determine their ash contents).
  • Process II the above process was generally repeated but using high speed stirring such that numerous air bubbles were created in the slurry and caused solids to float rather than sediment out. Accordingly in this process on each of the two occasions the underlying slurry was separated from the floated-out solids rather than the sediment being separated from the overlying slurry.
  • Process III the chosen additive was added to a sample of the slurry and the mixture then subjected to froth flotation using froth flotation apparatus of the Leeds cell design.
  • the floated-out matter was separated from the underlying slurry and the latter collected and the former returned with added water to the Leeds cell which was then operated again.
  • the floated-out matter was again separated from the underlying slurry and both collected.
  • the floated-out matter was filtered, dried and weighed (to determine the product yield) and burnt and re-weighed (to determine the ash content of the product).
  • the two portions of collected separated slurry were separately filtered and the residues dried, weighed and burnt.
  • Example 1.6 in the Table is shown as being conducted according to Process II. However, although high speed stirring was used such that numerous air bubbles were created in the slurry, the solids sedimented out rather than floated and thus the separation steps were conducted in accordance with Process I rather than Process II.
  • Examples 1.1 and 1.2, which use Process I, are included only for comparison purposes.
  • the product ash contents are high, signifying a substantial proportion of shale in the product.
  • Example 1.3, which uses Process II, gives a much lower ash content but the yield is low.
  • Examples 1.5, again using Process II, gives a good yield of low ash content and the high ash contents of the tailings signify that little coal is lost in the tailings. The contrast with Example 1.2 using Process I but otherwise generally similar is very marked.
  • Example 1.6 is included only for comparison purposes and shows that Process II is not effective in the absence of the polyvinylether: whilst the product yield is high, the product has a high ash i.e. shale content.
  • Example 1.9 included only for comparison purposes, shows that if gas oil and frother are used in Process III without the polyvinylether a greatly reduced yield results.
  • Process IV which was the same as Process III described in Example 1 except that froth flotation was done once instead of twice, was carried out on an aqueous coal/shale slurry from a coal preparation plant using in one series of experiments an additive composition according to the invention and in another series of experiments the froth flotation oil in current use on the plant at the time.
  • the ash content of the solids in the slurry was 36.5% by weight, and of the solids 69% by weight were of particle size less than 53 microns.
  • the composition of the additive was, by weight:- 60% gas oil 20% mixture of polypropylene glycol ethers (TEEFROTH G) 20% polyvinyl ethyl ether (LUTONAL A25)
  • TEEFROTH G polypropylene glycol ethers
  • LUTONAL A25 polyvinyl ethyl ether
  • the results obtained using the additive composition are, over the range of dosages investigated, superior to those obtained using the conventional froth flotation oil, and particularly at high dosages are characterised by higher weight yields and lower product ash contents. For example at a dosage of 1.21 kg ash is reduced by 5.6% by weight and the yield increased by 2.8% by weight.
  • Process IV as described in Example 2 was carried out on a sample of particle size less than 105 microns screened from a run-of-mine coal/shale slurry in which the particle size of the solids was less than 500 microns.
  • the ash content of the solids in the sample was 45% by weight. 86% by weight of the solids in the sample had a particle size of less than 20 microns and an ash content of 46.4% by weight, and the remaining 14% by weight contained 30% by weight ash.
  • Example 2 The additive composition described in Example 2 was compared with a proprietary froth flotation oil used in a conventional froth flotation process.
  • a bulk feed sample of a coal/shale slurry was screened at 500 microns. Part of the sample was retained for normal froth flotation for comparison purposes and the remainder was classified in a 5 cm hydrocyclone.
  • the underflow was diluted with water to approximately 6% solids by weight and similar froth flotation treatments were carried out on portions of the diluted material to those carried out on the overflow material.
  • Froth flotation was also carried out on the retained screened feed sample using the froth flotation oil normally used to treat the particular coal/shale slurry in practice.
  • results demonstrate the benefits to be obtained by using a hydrocyclone to split the feed for a conventional froth flotation into one fraction containing fine particles of a size predominantly less than 50 microns (overflow) and another fraction containing relatively coarse particles of a size predominantly in the range of 50 - 500 microns (underflow) and then treating the fraction containing the fines by the method of the invention and the other fraction by a conventional froth flotation process.

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  • Solid Fuels And Fuel-Associated Substances (AREA)
  • Extraction Or Liquid Replacement (AREA)

Claims (13)

  1. Verfahren zur Rückgewinnung von Feinkohle aus einer wäßrigen Trübe, die auch als feiner Feststoff verteilte Berge enthält, bei dem man Feinkohle hydrophobiert, das entstandene Gemisch rührt, zur Blasenbildung Gas in die Trübe einleitet, wodurch die gebildeten Feinkohleflocken zum Aufschwimmen gebracht werden, und die darunterliegende, Berge enthaltende Trübe verwirft, dadurch gekennzeichnet, daß die Feinkohle durch Zusatz eines hydrophoben Polyvinylethers in einem flüssigen organischen Träger zur Trübe hydrophobiert wird.
  2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß der hydrophobe Polyvinylether Polyvinylethylether oder Polyvinylisobutylether ist.
  3. Verfahren nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß der flüssige organische Träger Gasöl, Dieselöl oder Kerosin ist.
  4. Verfahren nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß man zur Unterstützung der Auflösung des Polyvinylethers ein mit dem Träger verträgliches Hilfslösungsmittel verwendet.
  5. Verfahren nach Anspruch 4, dadurch gekennzeichnet, daß das Hilfslösungsmittel ein aromatisches Lösungsmittel ist.
  6. Verfahren nach Anspruch 5, dadurch gekennzeichnet, daß das aromatische Lösungsmittel Toluol oder Xylol ist.
  7. Verfahren nach Anspruch 4, dadurch gekennzeichnet, daß das Hilfslösungsmittel ein paraffinisches Lösungsmittel ist.
  8. Verfahren nach Anspruch 7, dadurch gekennzeichnet, daß das paraffinische Lösungsmittel Hexan ist.
  9. Verfahren nach einem der Ansprüche 1 bis 8, dadurch gekennzeichnet, daß ein Schäumer verwendet und das Verfahren als Schaumaufbereitung in einer Schaumflotationszelle durchgeführt wird.
  10. Verfahren nach Anspruch 9, dadurch gekennzeichnet, daß der Schäumer Methylisobutylcarbinol oder ein Gemisch von Polypropylenglykolethern ist.
  11. Verfahren nach Anspruch 9, dadurch gekennzeichnet, daß man eine aus 5 - 25 Gew.-% hydrophobem Polyvinylether, 5 - 25 Gew.-% Schäumer und 50 - 90 Gew.-% flüssigem organischen Träger bestehende Zusatzzusammensetzung in einer Menge von bis zu 10 kg pro Tonne Trübefeststoffe einsetzt.
  12. Verfahren nach Anspruch 11, dadurch gekennzeichnet, daß man die Zusatzzusammensetzung in einer Menge von 0,5 - 5 kg pro Tonne Trübefeststoffe einsetzt.
  13. Zusatzzusammensetzung zur Verwendung bei einem Verfahren zur Rückgewinnung von Feinkohle nach Anspruch 9, dadurch gekennzeichnet, daß die Zusammensetzung aus 5 - 25 Gew.-% hydrophobem Polyvinylether, 5 - 25 Gew.-% Schäumer und 50 - 90 Gew.-% flüssigem organischen Träger besteht.
EP87304307A 1986-05-14 1987-05-14 Feinkohlegewinnung Expired - Lifetime EP0246105B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB868611747A GB8611747D0 (en) 1986-05-14 1986-05-14 Recovering coal fines
GB8611747 1986-05-14

Publications (3)

Publication Number Publication Date
EP0246105A2 EP0246105A2 (de) 1987-11-19
EP0246105A3 EP0246105A3 (en) 1989-04-05
EP0246105B1 true EP0246105B1 (de) 1992-03-18

Family

ID=10597858

Family Applications (1)

Application Number Title Priority Date Filing Date
EP87304307A Expired - Lifetime EP0246105B1 (de) 1986-05-14 1987-05-14 Feinkohlegewinnung

Country Status (5)

Country Link
EP (1) EP0246105B1 (de)
DE (1) DE3777448D1 (de)
ES (1) ES2040251T3 (de)
GB (3) GB8611747D0 (de)
ZM (1) ZM1592A1 (de)

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5021165A (en) * 1987-06-10 1991-06-04 Conoco Specialty Products Oil and water separating system with hydrocyclone and floatation device
GB8726857D0 (en) * 1987-11-17 1987-12-23 Fospur Ltd Froth floatation of mineral fines
US5298167A (en) * 1992-12-10 1994-03-29 Arnold Kenneth E Method for separating immiscible liquid
JPH08511728A (ja) * 1994-04-13 1996-12-10 フィリップス エレクトロニクス ネムローゼ フェンノートシャップ 水性分散液の加熱凝集方法
CN101578140A (zh) * 2006-12-06 2009-11-11 国际壳牌研究有限公司 用作泡沫浮选捕集剂的具有低芳烃、硫和氮含量的正链烷烃和异链烷烃
CN101823025B (zh) * 2010-04-01 2013-02-13 西安科技大学 一类煤炭浮选剂及其制备方法
CN103394416B (zh) * 2013-08-22 2014-11-26 陕西延长石油矿业有限责任公司 一种煤炭浮选剂及其制备方法
CN105750092A (zh) * 2016-03-10 2016-07-13 徐州工程学院 一种新型选煤捕收剂及其制备方法
CN105728200A (zh) * 2016-03-29 2016-07-06 江苏尧舜机械科技有限公司 一种选煤复合药剂及其制备方法
CN111135960B (zh) * 2020-01-16 2021-11-19 辽宁科技大学 一种实验室用微泡浮选机及其工作方法

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL254791A (de) * 1959-08-11 1900-01-01
NL254793A (de) * 1959-08-11 1900-01-01
AU5856080A (en) * 1979-06-01 1980-12-04 Calgon Corporation Flotation circuit additive
US4304573A (en) * 1980-01-22 1981-12-08 Gulf & Western Industries, Inc. Process of beneficiating coal and product
US4466887A (en) * 1983-07-11 1984-08-21 Nalco Chemical Company Polymer collectors for coal flotation
US4532032A (en) * 1984-05-30 1985-07-30 Dow Corning Corporation Polyorganosiloxane collectors in the beneficiation of fine coal by froth flotation
US4605420A (en) * 1984-07-02 1986-08-12 Sohio Alternate Energy Development Company Method for the beneficiation of oxidized coal

Also Published As

Publication number Publication date
GB8711401D0 (en) 1987-06-17
ES2040251T3 (es) 1993-10-16
EP0246105A2 (de) 1987-11-19
GB8611747D0 (en) 1986-06-25
GB2225260A (en) 1990-05-30
GB2190310A (en) 1987-11-18
GB2225260B (en) 1990-08-29
GB8924001D0 (en) 1989-12-13
GB2190310B (en) 1990-10-17
DE3777448D1 (de) 1992-04-23
EP0246105A3 (en) 1989-04-05
ZM1592A1 (en) 1992-11-30

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