WASTEPAPER TREATMENT METHOD

METHODE DE TRAITEMENT DES DECHETS DE PAPIER

English Abstract

ABSTRACT OF THE DISCLOSURE
The invention is directed to a method and
apparatus for treating wastepaper, wherein a
selective flotation of suspension in a selective
flotation system is carried out in multiple calls.
Flotation froth is fed to hydrocyclone which
produces two fractions, with a core fraction
including lightweight particles and gas being
drawn from the core and discarded, preferably at
the upper end, and with a heavy fraction recycled
to the selective flotation system.

Claims

WHAT IS CLAIMED IS:
1. A method of treating wastepaper,
comprising the steps of:
providing a selective flotation system
having a plurality of flotation cells;
removing flotation froth from at least
one of a first and second flotation cell of said
plurality of flotation cells;
separating or purifying flotation froth
from the remainder of said plurality of flotation
cells with a hydrocyclone, said hydrocyclone
providing a core fraction and a heavy fraction,
said core fraction comprising lightweight
particles and gas, said heavy fraction comprising
relatively fewer contaminants than said core
fraction;
drawing said core fraction from an upper
end of said hydrocyclone; and
recycling said heavy fraction from a
bottom end of said hydrocyclone to said first
flotation cell of said selective flotation system.
2. The method of Claim 1, wherein said
removing step comprises discarding said flotation
froth removed from said first and second flotation
cells.
3. The method of Claim 1, comprising the
further step of separating or purifying said
flotation froth removed from said first and second
flotation cells with a second hydrocyclone, said
second hydrocyclone providing a core fraction and
a heavy fraction, said core fraction comprising
lightweight particles and gas, said heavy fraction
comprising relatively heavier particles and fewer
contaminants than said core fraction;
drawing said core fraction from an upper
end of said second hydrocyclone; and

recycling said heavy fraction from a
bottom end of said second hydrocyclone to said
first flotation cell of said selective flotation
system.
4. The method of Claim 1, wherein said
recycling step comprises recycling said heavy
fraction from a bottom end of said hydrocyclones to
said first flotation cell of said selective
flotation system, via a mixing chamber.
5. An apparatus for treating wastepaper,
comprising:
a primary flotation system having a
plurality of flotation cells;
means for removing flotation froth from
at least one of a first and second flotation cell
of said plurality of flotation cells;
a hydrocyclone connected to a remainder
of said plurality of flotation cells for
separating or purifying flotation froth from said
remainder of said flotation cells, said
hydrocyclone providing a core fraction and a heavy
fraction, said core fraction comprising
lightweight particles and gas, said heavy fraction
comprising relatively fewer contaminants than said
core fraction, said hydrocyclone including a drain
pipe connected to said first flotation cell for
recycling said heavy fraction to said primary
flotation system.
6. The apparatus of Claim 5, wherein said
drain pipe is connected to said first flotation
cell via a collection vessel and a mixing chamber.
7. The apparatus of Claim 5, further
comprising a second hydrocyclone for separating or
purifying said flotation froth removed from said
first and second flotation cells, said second
hydrocyclone providing a core fraction and a heavy

Description

- 21~12~
E~an~--Di~t~r DorPl l~g~r
S~erh~r~l Veh
'rhe preuaent inv~nt~ on ~o~ a m~hod A~ld
2Ipparatu~ ~or ~a~tepaper l:~e~ent.
I~h~ pr~bl~r~ underly~ g th~3 pr~3snt in~nt:Lon
1-~ to provid~a a ~y~t~m R* ~mpl~ d~lgn an~l having
rala~lvely low ~7ast6l ac:or~al.
It 1~ ~own in th~ ~rt tc? r~3mo~lre ~roth ~m
~el~ot~ve ~lots~ion ~y6~e3n. ~rh6l frot:h i nc:lud~e
6~a~e~, d~ rt palrticleF: asld ~ibe!r~ . A ~3scondary
~lota~i :?n oy~t~m m~y bla aor~ne{:t~d tn ~ pximary
~lota~ ys~ or ror~3ving the ~ib~r~3 ~ro~ ~he:
~rot~
Wh~t 18 n~de~d in th~ art 1~ a ~33thod ~nd
~p~ratu~ :tor trnatln~ W~st~pAp~r whl~h ~oe~ not
utiliz~ a sosondars~ ~lotation ~yst~
In on~ or~ tnar~o~ 5 I;h~l pr~nt lnv~ntion
compr~eo~ a me~hod ~ p~aratu~ ~or tr~ ng
~2ls~ep~psrt wh~r~ln a ~elçct~ve :~lot~tion o~
E~u~p~ lon ln a e~lective :elo~tion ~;y~st2m ~
carried~ ou~: ln ~ultip~o cell~ . Flo~atio2~ ~roth 1;
~d to a hy~ro~yelt)ne whl~h pro~uc-3~ twc~
i~rac~ion6;, w~ kh a c:ore frElctl~n in~::luding
1~ ght~igh~ pa~tic~le~ arld g~ b~ing drawn ~xorn ~h~
aore~ . n~l t~i~cs~rde~ pr~r~bly at th~ Upper ~nd,
~n~l With a h~vy i~raction re~ycled ~o thla
8el~4ti~e Plo~at~ on ~y~t2m.
Ar~ ~dv~n~as~e o~ the pre~ent invont$on l~ l:hat
th~ 0n~1ar~ ~lolc~t~n 13y~tem 1~ ~limi~ate~d,
therQby pro~riding ~a~ 3r c~ trol and operatiorl o~
th~ o~t~r~ll sy~tem .
.
.: '
. . .
. . : , :
. . ~ : -
. :
:' , , ' ' ' .... . :' . . : . ' ~ ' ' '
.. . . .. .

21~22~
~h~ v~-~ntior~d and othor ~t~
~nd e.d~r~ntage6 o~ t~is $nv~ntion, ~nd ~h~ ~anner
~ att~lning~ thesll, w~ll beco~e ~ors~ appa~nt ænd
t~o ln~tsntlon wlll ~a bet~:c und~r~'coocl }~y
r~r~nca to th~ ~ollowlng d~ ription 4~ an
~odim~n~ o~ in~r~nt~ on t~X~n in oorlj~nct~on
with tl~ ompa~l:ying d~win~, ~dhs~ra~n:
Flg. 1 i~3 a ~ Aatic illu~ation o~ an
~sodlall~nt Or ~ r~n~ ~n~n~ioa~.
Corr~ponding ~ r~nc~ ch~racts~s in~lic~at~
corr~ponding pZl~ oughout tha ~svsral vlew~.
. . q~ ~xs~pllSlcat~on ~at out: h~ in llluE~træltQ~ ona
e~d ~odlm~nt o~ th~ vention, in one
~o~ d s~ æx~pll~lcatlon 1~ not to b~
con~ d a~ tirlg th~ ~COp@ of ~he inv~ntlon
in ~ny mann~
01ecti~e i~lo~;~l;ioA ~ t~ 1 ( i o J~ ma~y
~0 ~lo~tion ~y~tem) inGlud~ inaivldu~ rially
~ang~d flo~a'clon ~all~ 10 rrom wni~ o~h ls~
r~mov~d ~n~o a Goll~ tion c:h~lt~ I ~hieh is d.l~rlde~
~nto ~ at p~ 12 ar~d a ~ ond pArl 121. ~h4
~ot~ o~ l~ir~ pa~t 12 s:~ khs ~:oL~tion. OhUt~,
~5 a~d P~ rab~Y On1Y 0~ th~ g~r~t ~lot7.ti~n C~ll
10, i~ di8~a~d~a. ~ ~m~nin9~ ~rO~ B1
~:ha~ COn~ Part 12' 0~ 1Q~1Q
~2aUt~ d V1a PU~P ~0 ~0 ~ hY~OCY~1On~ 3
ha~ a~ it~ top a~ ~ u~t 4 wit;h ~ d~ç~2l~slrlg
~i~ad 7~ ~o~ ~ dsl~c~ lahl~3 ~a~q~ous ~o~o frao~ n,
e.n~ at 1:h8 ~o~:~a~ a dxain pi~ o~ a h~avy
c1:ion Go~a~niDg r~la~ ely i~we~ dlrl:
nd, thu~, i8 p~rl ~i~ad l~y th~ ee~2ara~:Lorl
pxoca~3., 'rh~s 9a8Roug 60XQ ~r~Ction a~.so ::on~aln~e a
c~rtain ~ounl: o~ $. ~ r~inder o~ th~
ar~ drain thsoug~ dr~ln plp- 5, alon~ ~th
.- . -
A . . , , ~ ,
' . ~
. ' ,'
"., ~, . , " ", , " ' '
,.' ' ~ . ~, .
. ' , ,,,: ' ' . , ,' ' :
' ' . ' '
'. ', '',
' '
. ' ~ ' :

2~01?,2~
~eï~tlvely s~n~ll amoun~ o~ dir~ p~r~icl~, anà ~re
r~cyc~ to the t~on~ og ~21~ctiv~ ~lotation
~y~t~ 1 , i . e ., to 4 rst ~lota~lo~ a411 ~0 oP
~lr~ p~rl: la. ~ydrocyclon~a 3 pr~or~bly ha~
S con~2a~ tap~ ard ~h~ d~ain ~o~ n~aYior
~ra~ion.
~h~ pre~nt ~nYar tlo~ ~o~ n~ inc:lude a
~c:~n~ry ~lota~on ~ys~m wh~ conn~ o
a~y ~lo~at~on ~y~ m 1.
0 ~ al50 pO~;oi~lo to ~4p~rate ri}~ro ~om
~a ~elu1 d ~u pen~lon o~ ths ~ and/or s~cond
flo~tlon 6all lG ~o:~, oxlly ~l~st c~ thQ
seleon~ hydrocyc:lo~. 3 rq!C~ Y08 thç~ ~ro~ sa~ all
r~ai~ing c~ by a i3~con~1 hy~ro~yclon~ 3~ oi~ a
lS ~r~c:or~d hyarocyGloI~ sy~t~a 4 ~ (With s~e
re~ nc~ a~ oth~r hydro~y~lorle 6y~ m, ~u~
ea~:h ~ vld~d wlt~ el prl~ ysalaol ) ~ Tha co~a
~aeq~ s~ hydrocyclon~ 3', po~ 3ly ~
~a~ou~ pr~rably a~lso d~ ca~:d~d (r~ er to
ao ~h-do~ t~atton ln 1:he ~lgu~
Roc:y::lin5~ o~ r~s~n~ lnvE3ntic~n ~rsvid2~ a
g~t~ loa~ llpon ~ ~3t ~ew ~l~t~ti~rl c:ells
10, bu~ o pr~vid~ ~ hlgha~ d~gr~30 o~ ~p~ra-
~ion o~ ~u~bn~lon pa~tl61~s in ~ o~h.
Sub~ o~ 10 a~s n~ c~ ~o a
ar.ti~ly ~i~h~r load~ ~o~ h~ nuD~er o~
C~211~11 10 ~l~o ~ b~ ar~a~d by 1 ~ he-
p~ vonlt~ P~ d~ n~a~ pl~x
n an~ 60n~o~, ~ec~ua~ a 6~0~
3Q fl~t~ o~ ~;y~t~ ~no~ ~ho~n~, ~whl~ if3
~:ot~n~on~lly u~qld, ~ ~ ~llml~t~d v
Dr~n ~ in9 ~5 ot~ hydrocy~lon~ 3 ~m~ e~ the
hoavy ~aation ir~to a ~oll~tion ~to~38~1 17, ~Ild 1
tr~ns~ort~d ~f~a ~mp ~g lto 2ll~xing eha~2~ ~a o~
~a~y ~lot~ion ~y~c~ 1.
.

2~2~
~h~ le thi8 lnvMntion ha~ b~en do~crl~ed ~
h~in~ a pr~err~d desi~, th~ ~res~nt ~nv~tLon
c~n bo ~ r modi~l~d w~thln ~h~ ~p~rl~ and
t~C:2pe oi~ ~liO ~l~closur~ ~hi~ application L~
S ~he~e~o~e lnl:~n~ to eov~r ~ny v~ri~t1on~ a,
o~ adap~a~io~s ot tA~ ~m~n~ion u~1ng it~ gQn~:al
H1~ B 2p~ a~n i8 iRt:enc~le)d
to COV6~ suclh d~apa~urcl% ~ro~ ~a p~ 3nt:
di~isclos~ s; co~n~ wlt:~in known or ~u~omary
SO pxac~:~c~a i~ ~a zlrt to wh1ch th1~ ~:nv~ntlon
p~ wh~ ll wi1;h1n th6a lim; t~
~p~nd~d ¢l~o
~.
- - .
.
: . -, , -
.
, ~'. , , . ~ '
.
... ; ~ ' ' ~- ' ' '' :
- . , , ~ -
.