CA1140081A - Classification of asbestos fibre concentrates - Google Patents
Classification of asbestos fibre concentratesInfo
- Publication number
- CA1140081A CA1140081A CA000285946A CA285946A CA1140081A CA 1140081 A CA1140081 A CA 1140081A CA 000285946 A CA000285946 A CA 000285946A CA 285946 A CA285946 A CA 285946A CA 1140081 A CA1140081 A CA 1140081A
- Authority
- CA
- Canada
- Prior art keywords
- chamber
- flow
- air
- exit
- weir
- 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
Links
Landscapes
- Preliminary Treatment Of Fibers (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
Improved separation of needles from opened fibres in an asbestos fibre line is achieved using a classifier in which an air entrained asbestos concentrate is formed into a stream-line flow and subjected to a stage of gravity separation followed by at least one stage of inertial separation.
Improved separation of needles from opened fibres in an asbestos fibre line is achieved using a classifier in which an air entrained asbestos concentrate is formed into a stream-line flow and subjected to a stage of gravity separation followed by at least one stage of inertial separation.
Description
~4~8~
!
This invention relates to the processing of asbestos ores and more particularly to a spicule classifier ana : concentrator for separation of the fibres in an asbestos milling plant Conventionally in such a plantO pxepared ore is first processad in a rock line in which thP fibre is separated from gangue by breaking it up in iberizers followed by screening to produce fibre concentrates which are further processed in fibre lines conventionally comprising successive stages of dedusting, scraening and fiberiæing.
The material entering the fibre lines ~rom ~he rock line comprises opened and unopenad fibre spicules in various forms and degrees of sepa.ration together wi~h debris and contaminants. The s~paration of these various components for further pxocessing or rejection as appropriate is one of th~ functions of the fibre lines~ Some compon2nts have proved rather difficult to separ~te: for example~ a proport.ion of the fibre, ~epending on the nature of the ore, will be in the form of 'needles'0 which axe needle-like bundles of fibres o-f generally uniform diameter. Thes~ tend to become matted toge'her with already separated asbestos ibre~ and thereafter are dificult to xe~uce to their component fib~es.
The presence o a signiicant proportion of such needles i.n the final product pre~ents the reinforcing proper-ties of th~
fibres from being fully realized.
T`he object of the pre~ent invention is to provide a spi~ule classifier and concentrator for incorpox~t~on in a fibre line ~hich can effectively ~lassify the various components of an asbe3t.0s fibre concen-tr~te, including ne~dles, according `~
1~0~81 : to the further treatment required. The use of suc'n a classiier anables the remainder o~ the fibre line to be gxea~ly simplified~
According to the inven~ion, a m~thod of classifying an asbestos fibre concentrate comprises entraining ~he concentrate in air forming the concentrate so entrained into a substantially horizontal streamline flow sufficiently prolonged to permit stratiEication oE different components of the concentrate under the influence of gravi~y0 in a first sta~e of separation capturing those components which sink to the bottom o~ the rlow, and in a second stage of separation subjeating the remainder of the flow to at least one stage of inertial separation in which the direction of the air 10w is changed sufficiently rapidly for components of higher inertia to escape from the flow and be captured~ In prac~ice the components captured from th~ bottom of the flow in the first stage of separation are rock, coarse spicules and platy waste, and - the components captured in the second stage ara cruay cleans and needles, opened asbestos fibres and dust remaining entrained.
Th~ needles a~d already opened fibres are thus separatea and prevented from matting in later stages o~ treatment.0 which in turn enables the needles to be satisfactorily reducea to opened fibre3~
A preferred form of apparatus comprises a casing defining an entry section~ a first chamber, a sç~ond cha~ber and an exit section, the entry section being a generall~
horizontally disposed streamlined duct having an entrance arranged to receive from a rock line an air-entrain~d flow !
of fibre concentrat~ the duct having a gradual transition into a horiæontally oblong exi~ into the first chamber, the exit being positioned at tha top of one sid~ wall of the ~irst chamher so as to direct a s~reamline flow of entrained spicules towards a weir dividing the first cha~ber from the second chamber, the height of the weir being adjusted so that rocX, coarse spicules and platy waste will fall sho~t of the top of tha weirD the second chamb~r having a deflecting membex extending downwardly from its top wall so a~ to cons~ain entraining air entering th~ chambe.r from the previous chamber to foll~w a sufficiently sinuous pa~h downwardq around the deflecting member that crudy cl~ans and needles escape the entraining air and are ca~ured by the chamber, the second chamber having an e~it for the entraining air in its far wall beyond the deflecting member and into the exi~ section~
The inventiQn is describea further wi~'n referenc~
: to the accompanying drawing, in s~hich:
Figure 1 is a plan view and Figure ~ is a ~er~ical section through apparatus in accordance wi'ch th~ ir.vention.
: The apparatus comprises an inlet pipe 1 which will usually be round and receives fxom th~ rock lin~ of an asbestos processing plant an air-entrained asbestos Eibre concentrateO This fibre concentrate will typically contain about 80% b~ weight of a.sbestos fibres and the entraining air should have a veloci~y of about 20 metres/sec, From the inlet pipe which should b~ straight and substantially horizontal :Eor a distance at leas-t 8 -t.imes its d.iam~terO
0~
the air entrained concentrate passe~ through a transition member in the ~orm of a streamlined duct 2 which provides a gradual transition from the cross-~ection of the pipe to a horizontally oblong coniguration of substantially ~he same cross-section. The flow through the pipe into the duct is thus rendered streamline, with the result that the less readily entrained components of the concentrate tend to gravitate toward~ the bottom of the flow. These components are rocX, coarse spicules and plat~ wa~te~
~rom the duct 2, the flow i~ dischar~ed through a horizontally oblong opening at the top o~ one side wall 7 of a ix~t chamber 3. The opposite wall o this chamber i3 formed by a weir 8 comprising a vertically adjustable top portion 9. The top portion 9 is adjusted so that at least th~ bulk of the streamline ~low from th~ duct 2 clears the top edge of the weir and enters a secona chamher 4~ whilqt the components which have gravitated to the bottom of the ~low fall short of the weir and fall to the bottom o~ the first cham~er whence they ~re removed through an air lock 10 and returned to the rock line for furth~r proce~sing. In a typical case and with the xate o flow already specifie~J
if the opening in the top o the wall 7 has a height o~ 15 cm~
then satisfacto.ry results will be achie~d with a chamher which is 60 cm wi~e, a~d in w~ich ths top of the weir i3 15-25 cm short of the top wall of the chamber.
Ths air flow passing over the top of the weir i~
deflected downwardly b~ a curved quadrant-shaped derlector mem~er 11 in the chamber 4 whenc~ it must again turn upwardly ~L4~
to reach an exit in khe far wall 12 of the chamber 4 to reach a further transition duct 5 through which the entraining air reache~ an outlet pipe 6. The change in direction of thP
air flow around the de~lector member 11 causes a centrifugal force to be applied to the entrained material which, i the : rate of change of direction is coxrect will be sufficient to cause crudy clean fibre and needles to escape from the flow towards the bottom of th~ chamb~r 4 whilst leaving du~t and already ~pened fibres still entrain~d. With the 10w rate previou~ly cons.idered, a deflector member 11 with a radius oE about 40 cm should provide sati factory re~ults, The crud~ clean fibre and needles are removed through an air .~ lock 13 ~or further treatment in a fibre line, and the air ~ stream leaving throu~h the exit pipe 6 is passed through a cyclone to remove the opened fibres and thence ~reated for dust removal by conven-tional techniques~
A further second chamber or chambers, including d~flector plates and operating as previously describe~, may be utilized if necessary, to achi~ve a greater deyree of ~0 s~paration: ho~sver, it is believed that a sin~le sacond chamber will usually be sufficient, It is ound that by using the separator describ2d above as the ini~ial stage of a fibre linP in an asbes-t.os fibre proce~s~ing plant, the nu~bsr of stages of treatment in the f.ibre line ma-~ be greatly reduced~ and the risk of needle~
becominy matted with opened fibre~s i~ greatly reduced~
!
This invention relates to the processing of asbestos ores and more particularly to a spicule classifier ana : concentrator for separation of the fibres in an asbestos milling plant Conventionally in such a plantO pxepared ore is first processad in a rock line in which thP fibre is separated from gangue by breaking it up in iberizers followed by screening to produce fibre concentrates which are further processed in fibre lines conventionally comprising successive stages of dedusting, scraening and fiberiæing.
The material entering the fibre lines ~rom ~he rock line comprises opened and unopenad fibre spicules in various forms and degrees of sepa.ration together wi~h debris and contaminants. The s~paration of these various components for further pxocessing or rejection as appropriate is one of th~ functions of the fibre lines~ Some compon2nts have proved rather difficult to separ~te: for example~ a proport.ion of the fibre, ~epending on the nature of the ore, will be in the form of 'needles'0 which axe needle-like bundles of fibres o-f generally uniform diameter. Thes~ tend to become matted toge'her with already separated asbestos ibre~ and thereafter are dificult to xe~uce to their component fib~es.
The presence o a signiicant proportion of such needles i.n the final product pre~ents the reinforcing proper-ties of th~
fibres from being fully realized.
T`he object of the pre~ent invention is to provide a spi~ule classifier and concentrator for incorpox~t~on in a fibre line ~hich can effectively ~lassify the various components of an asbe3t.0s fibre concen-tr~te, including ne~dles, according `~
1~0~81 : to the further treatment required. The use of suc'n a classiier anables the remainder o~ the fibre line to be gxea~ly simplified~
According to the inven~ion, a m~thod of classifying an asbestos fibre concentrate comprises entraining ~he concentrate in air forming the concentrate so entrained into a substantially horizontal streamline flow sufficiently prolonged to permit stratiEication oE different components of the concentrate under the influence of gravi~y0 in a first sta~e of separation capturing those components which sink to the bottom o~ the rlow, and in a second stage of separation subjeating the remainder of the flow to at least one stage of inertial separation in which the direction of the air 10w is changed sufficiently rapidly for components of higher inertia to escape from the flow and be captured~ In prac~ice the components captured from th~ bottom of the flow in the first stage of separation are rock, coarse spicules and platy waste, and - the components captured in the second stage ara cruay cleans and needles, opened asbestos fibres and dust remaining entrained.
Th~ needles a~d already opened fibres are thus separatea and prevented from matting in later stages o~ treatment.0 which in turn enables the needles to be satisfactorily reducea to opened fibre3~
A preferred form of apparatus comprises a casing defining an entry section~ a first chamber, a sç~ond cha~ber and an exit section, the entry section being a generall~
horizontally disposed streamlined duct having an entrance arranged to receive from a rock line an air-entrain~d flow !
of fibre concentrat~ the duct having a gradual transition into a horiæontally oblong exi~ into the first chamber, the exit being positioned at tha top of one sid~ wall of the ~irst chamher so as to direct a s~reamline flow of entrained spicules towards a weir dividing the first cha~ber from the second chamber, the height of the weir being adjusted so that rocX, coarse spicules and platy waste will fall sho~t of the top of tha weirD the second chamb~r having a deflecting membex extending downwardly from its top wall so a~ to cons~ain entraining air entering th~ chambe.r from the previous chamber to foll~w a sufficiently sinuous pa~h downwardq around the deflecting member that crudy cl~ans and needles escape the entraining air and are ca~ured by the chamber, the second chamber having an e~it for the entraining air in its far wall beyond the deflecting member and into the exi~ section~
The inventiQn is describea further wi~'n referenc~
: to the accompanying drawing, in s~hich:
Figure 1 is a plan view and Figure ~ is a ~er~ical section through apparatus in accordance wi'ch th~ ir.vention.
: The apparatus comprises an inlet pipe 1 which will usually be round and receives fxom th~ rock lin~ of an asbestos processing plant an air-entrained asbestos Eibre concentrateO This fibre concentrate will typically contain about 80% b~ weight of a.sbestos fibres and the entraining air should have a veloci~y of about 20 metres/sec, From the inlet pipe which should b~ straight and substantially horizontal :Eor a distance at leas-t 8 -t.imes its d.iam~terO
0~
the air entrained concentrate passe~ through a transition member in the ~orm of a streamlined duct 2 which provides a gradual transition from the cross-~ection of the pipe to a horizontally oblong coniguration of substantially ~he same cross-section. The flow through the pipe into the duct is thus rendered streamline, with the result that the less readily entrained components of the concentrate tend to gravitate toward~ the bottom of the flow. These components are rocX, coarse spicules and plat~ wa~te~
~rom the duct 2, the flow i~ dischar~ed through a horizontally oblong opening at the top o~ one side wall 7 of a ix~t chamber 3. The opposite wall o this chamber i3 formed by a weir 8 comprising a vertically adjustable top portion 9. The top portion 9 is adjusted so that at least th~ bulk of the streamline ~low from th~ duct 2 clears the top edge of the weir and enters a secona chamher 4~ whilqt the components which have gravitated to the bottom of the ~low fall short of the weir and fall to the bottom o~ the first cham~er whence they ~re removed through an air lock 10 and returned to the rock line for furth~r proce~sing. In a typical case and with the xate o flow already specifie~J
if the opening in the top o the wall 7 has a height o~ 15 cm~
then satisfacto.ry results will be achie~d with a chamher which is 60 cm wi~e, a~d in w~ich ths top of the weir i3 15-25 cm short of the top wall of the chamber.
Ths air flow passing over the top of the weir i~
deflected downwardly b~ a curved quadrant-shaped derlector mem~er 11 in the chamber 4 whenc~ it must again turn upwardly ~L4~
to reach an exit in khe far wall 12 of the chamber 4 to reach a further transition duct 5 through which the entraining air reache~ an outlet pipe 6. The change in direction of thP
air flow around the de~lector member 11 causes a centrifugal force to be applied to the entrained material which, i the : rate of change of direction is coxrect will be sufficient to cause crudy clean fibre and needles to escape from the flow towards the bottom of th~ chamb~r 4 whilst leaving du~t and already ~pened fibres still entrain~d. With the 10w rate previou~ly cons.idered, a deflector member 11 with a radius oE about 40 cm should provide sati factory re~ults, The crud~ clean fibre and needles are removed through an air .~ lock 13 ~or further treatment in a fibre line, and the air ~ stream leaving throu~h the exit pipe 6 is passed through a cyclone to remove the opened fibres and thence ~reated for dust removal by conven-tional techniques~
A further second chamber or chambers, including d~flector plates and operating as previously describe~, may be utilized if necessary, to achi~ve a greater deyree of ~0 s~paration: ho~sver, it is believed that a sin~le sacond chamber will usually be sufficient, It is ound that by using the separator describ2d above as the ini~ial stage of a fibre linP in an asbes-t.os fibre proce~s~ing plant, the nu~bsr of stages of treatment in the f.ibre line ma-~ be greatly reduced~ and the risk of needle~
becominy matted with opened fibre~s i~ greatly reduced~
Claims (5)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of classifying an asbestos fibre concen-trate, comprising entraining the concentrate in air flowing at a predetermined velocity, passing the air entrained flow of concentrate through a transition zone to provide substan-tially horizontal streamline flow sufficiently prolonged to permit stratification of components of the concentrate under the influence of gravity, in a first stage of separation causing the air entrained flow to pass over a weir to cap-ture those components which have sunk to the bottom of the flow, in a second stage of separation subjecting the remain-der of the flow to at least one stage of inertial separation in which the direction of the airflow is changed downwardly, smoothly but sufficiently rapidly for components of higher inertia to escape from the flow and be captured, and ex-hausting the airflow and the material remaining entrained therein.
2. A method according to Claim 1, wherein the compo-nents captured from the bottom of the flow in the first stage of separation are rock, coarse spicules and platy waste, and the components captured in the second stage are crudy cleans and needles, opened asbestos fibres and dust remaining entrained.
3. Apparatus for classifying an asbestos fibre con-centrate, comprising a casing defining an entry section, a first chamber, a second chamber and an exit section, the entry section being a generally horizontally disposed streamlined duct having an entrance arranged to receive from a rock line an air-entrained flow of fibre concentrate, the duct having a gradual transition into a horizontally oblong exit into the first chamber, the exit being positioned at the top of one side wall of the first chamber so as to direct a streamline flow of entrained spicules ..... 6 towards a weir dividing the first chamber from the second chamber, the height of the weir being adjusted so that rock, coarse spicules and platy waste will fall short of the top of the weir, the second chamber having a deflecting member extending down-wardly from its top wall so as to constrain entraining air entering the chamber from the previous chamber to follow a sufficiently sinuous path downwards around the deflecting member that crudy cleans and needled escape the entraining air and are captured by the chamber, the second chamber having an exit for the entraining air in its far wall beyond the deflecting member and into the exit section.
4. Apparatus according to claim 3, wherein the velocity of the air flow in the entry duct is about 20 metres/sec, the height of the exit of the entry duct is about 15 cm, the height of the opening above the weir into the second chamber is about 15-25 cm, the distance from the exit of the entry duct to the weir is about 60 cm, and the deflector member is quadrant shaped with a radius of about 40 cm.
5. Apparatus according to claim 3 or 4, comprising a plurality of second chambers arranged in series.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000285946A CA1140081A (en) | 1977-09-01 | 1977-09-01 | Classification of asbestos fibre concentrates |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000285946A CA1140081A (en) | 1977-09-01 | 1977-09-01 | Classification of asbestos fibre concentrates |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1140081A true CA1140081A (en) | 1983-01-25 |
Family
ID=4109450
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000285946A Expired CA1140081A (en) | 1977-09-01 | 1977-09-01 | Classification of asbestos fibre concentrates |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1140081A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2016064546A1 (en) * | 2014-10-22 | 2016-04-28 | Exxonmobil Upstream Research Company | Horizontal-flow oil sands separator for a solvent extraction process |
-
1977
- 1977-09-01 CA CA000285946A patent/CA1140081A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2016064546A1 (en) * | 2014-10-22 | 2016-04-28 | Exxonmobil Upstream Research Company | Horizontal-flow oil sands separator for a solvent extraction process |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |