Note: Descriptions are shown in the official language in which they were submitted.
SEhlT ~Y:D,~VIES & C9LLIS0;'~ 3~ 17'07; .~ELl3~V~ t;E~4~ 00~ fj
,,.~
JO PO/I 1~76 2 ~ 1 4 ~/AO~J~13~
-- 1 --
PROCESS ~OR ~OR~IN~ WATER ~13SIST~N~
MAGNESIAN C:EMENT INTRODUC~ION
The pre~ L; lnv~ntion ~elate~3 t4 a pro~c~s~ for
producing m~ne~ian cl3ment~ tious materlal~ ~nd
particularly, ~ut not es~entiall~ to ~e prod~lction of
magne~3ium ox~chlorlde hyd:rate and m~gnl3sium ~xysulphate
10 hyd~ate c~E3mentitious compo~itlon~ o~en knowrl as So~l
men~
BACRC~RC~uND ~ ~R I~ENq~ N
-
15 1. ~2~Inv~ation
Magnesium cem~nts b~sed on r~e:tior~ o~ m4~ne~ium
oxide wlth In~gne i-lm c:;hlorlde or ~ lph~ate h~ve heen known
fo~ a long ~ime. ~3uch a cem~nt ~o~med wl~h magnes:Lum
~0 c~hlor:~de, in parti~;ula~ conlmonly known as Sor~l
cemen~. ~his magne~ium ox~c:hlorlde ~ydri~te C;~men-t, when
cured, i~ yenerally chara::-t6~ri~e~ l~y th~ pr~senc~ of 9;1le
cr~r3talline compoun~2 SMg{ OH )2 ~ Mg~'12 . a~;~o an~ior
3~5g(0H)2.M~C~ .8~20, the rel~tlt7e propor~ion~ o~ the t:wo
25 ~onlpound~ dependlnr~ on -th~ s~oi~:hl~m~tr~r of ~h~ ::ured
mixtuIe . Formati~n o~ th2 5Mg~ O~ 2 . ~ 20 cotnpound
18 gene:~all~ pref~rr~dq OfteI~ on ~ns~, -She Cem~nt,
e~pecl~lly at the ~ur~cer c:arbona~ fo~m another
ar~at~lllne. c~s)mpound, My~ ~H~ Mg~12~ CO3 ~H2~ These
30 magn~sium ox~c:hl c~ide hydr~t~3 cemen-titio~ materlal s are
renown~3d for ~h~3ir ultlnlate hl~h s~en~th and ~or the
rapidlty with whlch ~hey ~ttaln ~uoh str~n~th, but
unfortun~tely su~i~er ~Yere ~ d~raslt~ hich have
di~cou~sge~ wlde use.
The ~o~emo~t prohlem wl~h m~gne~31um o~yahlorid~
cem~3nts is ~he~ir la~k of ~ter r~3~ig1:anGe, :~or~ i~fter
___
~JBST17 lJTE S~l~ET
SEi~T BY:DAVIES & COLLISON ; 3~ 91: 17:0~ lELBOL'R~E~41~ ~61 ~0~)0 ,~ f~
g76 2 ~ P~AU~/O~
-- 2 --
appr~nia~le cont~çt w~ th wate:~, dr~stic strens~th lo~ and
even tot~l disint~r~tlon c:an ocallr. P~csocia~ed wlth the
laok of wa~er re~ ance ls the pr~blem of corro~2iOn
arl S~ n~ from the lar~e amount~ of ma~n~sium c:hloride
5 leaohing ~om the c~ment upon con~act w~ th water. The
presence ~nd ll~ra~lon of ~olubll3 salts in the cured
cements al~o c:ausef~3 a~flore~cenc:e problem~.
th~
The prior art tea:::he~3 that mlmerou~ ~tten~p-~s have
bQen mad~e to ~olv~ th~ prl3blem of lack of wat~r
resl~tance in magnesium oxych~oride Cbmerlt Many
addit~ ve~ ha~e been t~c2ted to lmprove the water
15 r~lst~nce ei~her by lnc:o~oration ~n the cem~ntl~ious
mlx prior to sAt ing or by appllc~tion to the se~ or
hardened c~3ment. 5uch a~ldi~ives have irlc:luded ~34d$un~
sillcate~, poly~ ateY, ethyl slli~:ate, waxes,
siliconefi~ st~a~ate8, llnseed oll ~nd phosphoric ac:id or
20 i~s solubl~ ~al~ How~ver, none o:e ~he~e a~ditiv~s h~v~
apparen~ly led to Gommercially wide~pread ~ eptanae of
nagne~l~m ox}~hloride s::ements ~xcep~ ln a few 3elcc:ted
area~ ~uch el~ ~3pe~lal~ty flooring.
Of the pr~iously propo-e:ed addltlveæ inco~porated ln
the magne~um oasychlorid~ mix prior tc: æe~ting phosphoric:
a~ld ar d Etodf um }lexam~t~phosph~ ppe~r to be ~upe~ior.
R. Smi~h~-Jahannsen ha~ r~cen~ly ~s~nclllded i~ U. ~i/r Pe~ten~
4,352,6~4 that pho~;phorlc; ac~d ~ pr~fe~rad ov~r l~s
~0 ~oluble ~;alts ~Y an addltive ir~ Qb~ainln~ a ~ater
r~3si~tant cured Sor~ eme~t of eufficient strenEIth for
use in the bulldinçl in~#try~ Hc)wever, phosph~ori~ ~cid
~ æ r~l~tlvely expen~lve ~nd l~ addltlo~ to th~ mag~esian
oxy~hlorlde c~me~ m~y m~ke ~he ~n~nt c::omm~rc~ ~lly
35 unvi~ le.
SU~S~Tl.lT~ ~hlEE ii
SENT BY:DAVIES ~ ~OLLISON : 3-10-~1: 17:~ ELRO~ E~ 00~ .~12~
`!o go/ll976 2 0 5 1 ~ 1 ~ PCr/AU90/~
Addition of spar~ngly ~oluble or ~ tantially
ins~olu~ e p~o~phate has El1~3o been propo~ed ~nr lmproving
th~s properties of Sc:~rel C:sment~3. The~e lnclut~e
5 phosphate~ c~r se~::ondary phosphate~ of calcium, m~gne~;ium
and othe~ alk~line earth me~als, ~lnc, alu~inium and
copp~r (US Pat~nts ~!,3Sl,641, 4,185,066 and 4,1~,570).
Howl3ver, all of th~ descrll~d phosphælte~3 a~e elthex acld
o~ ne~r~l phc~ph~te~;. 8~1c ph~sph~teE or
10 hydroxypho~phE~te~, ~;uch ~13 cr~ndalllte, milllslts~,
~ravelllte and hy~ro~yapati~e, ar~d ~luoropho~;ph~te8, suah
a~ fluorapati~e, all fotlnd oc:curlng nat~rally as~
phosph~tlc: mlneral~, ha ~t~ no~ een pr~posed ~o~ imp~oving
the properties of Sor~l oQments dlle to thelr high r -
15 ins~lubllity ~nd ine~tne~R which results in no ben~fi~whatso~ver in lmp~ovlr~g the prop~rtie~ o~ !~;orel cement.
lMAR~' OF ~E INVENTI~N
It iS ~n ~i3J~3c~ Of ~he present lnventlon to provide
an imprc ved proce~s ~or proaucin~ a wat~3r resl8ti~nt
magnesian cem~n~itlou~ ma~rlal~
~c:cordlng to the pre~nt inven~ion, a w~ter
~5 r~t31Rtant m2~ne81an c:e~nentitious pr~oduc:t 1~; pr~du~d by
admlxlng p~r~iculBt~a phosphR~la m~t~lal with a re~c~ive
m~neslunl ox~ d~3 ~Oll~C:~ m~t~ri ~ m~gn~ m chloride
~nd/o~ m~gne~ium ~ulph~te~ ource m~erlal ~nd ~u~1qient
w~t~r ~o pro~ e a wnrka~le elurr~ and ~atking ~he
30 ~lur~yr ~nd wherein the ph~ph~ c m~eri~l compri~ an
insoluble b~C~t~, hydro~y andtor f luoro pho~pha tic mlneral
m~te~ l whi~h ~ 'civat d at le~ t by ~artlal
a~:ldula~ on~
~5 ~ur~}~er accor~lrlg t~ the pre~en~ vention th~re is
provlde~ a m~S~neslar~ cem~ntit~ou~ prod~c:t when prc)duc~ed
by ~he proce~ de~cribed in the imsnediat~ly prec~ing
S~J~s~lTuTE 51~~ 1
~,
~ENT BY:D~VIES & ~OLLISON ; ~-10~ 17:09 ; .~ELEO~R.~E~ 0~0 :~13~
g76 2 ~ PC~AU~0/00132
~ 4 -
pa~gr~ph.
By the pre~ent ln~entlon lnsoluble pho~phatlc
mineral materi~l ca~ be readlly ln~orpor~te~ lnto a
5 mAgnesi~rl CemRntitiOu~ mat~ria~ to promote water
r~3slstAnCe ~nd superlor long terln mechanlc~l properties.
Thi~ ~as ths ad~r~nt2ge of bell g ~bl~ to utili~e
relativ~ly ch~p phosphatic Rour ;:~ mate~ial to 1Inprove
the physi~al prop~rti~s o~ ~a~nes~an ~e~nt~.
19
A ~ound ~n the pre~ent invention, Addition of the
~n301uble basic, hydrox~phoæphata and~or fluorophosphat~
mlne~al materi~ls to the ce~nt mix confer~ no water
resi~tance ~ene~i~ to th~ cu~d ~em~nt unles~ they can ~e~'
a~tiva~ed. The water sQluhil~ty of ~ magnesian cem~nt
ineorpora~in~ such lnacti~2t~d inso~uble miner~l
materi~ls i~ in th~ range ~5 to 30~, usu~lly about 27~.
Solublllty is a m~asure of perc~ntag2 w~l~h~ los~ after
be~ng su~Qcted to e wat~r ~r~m~t. In th~s inven~lon
it has been di~covered th~ such benef~cial acti~ation of
insolubla pho~phatlo mlnerals, parti~ul~rly b~ ic,
hyd~xy- a~d/or fluoro-ph~pha~e~ al~h~u~h others may 4e
~ppropriate, c~n ~e ~chi~ve~ by pa~tlal acidula~ion,
optionally wi~h ~ pre-calolning ~t~p. The p~rtial
acldulation o the pho~p~atl~ miner~l ms~ri~l may he
carried out ~ore, durlng or atsr i~ ~dditlon to the
n~ment~ ~f~er such actlvatl~n, the pr~sence of ~he
pho~pha~l~ m~t~r~l in ~h~ ~ement conf~rQ a ~i~nlficant~y
incr~ased w~ter xesi~tanc~ to the ~ement o~ ZD~ or 1~5,
3~ pre~era~ly a~ou~ lD~ or le~ ~nd mo~t p~afer~bly ~40~t 7~
or le38. A m~nesi~n oeme~t h~vlng ~ w~ter ~olubill~y of
~he ord~r o~ 10-20% m~ ~e mo~ appr~pr~ate ~s a fil~r
but at lower level~ ~ay b~ re~di?y ~s~d in stru~ural
~it~a~ion~. In additlon to ~h~ advantageousl~ lvw ~a-ter
sol~blllty char~eri~lc~, the mechani~al properties,
p~rti~ul~rly ~ompres~lon ~tren~thr m~y only deg~ad~
rli~htly over ~xtende~ p~lod~ ~f ~l~e, ln s~me ~ases
SUBSTlTUT~ SI~Eli
~._
SENT ~Y:DAVIES ~ ~OLLISON , .3-10-~1 ; 17~ EL~()LR~E~ 000
~ Mf11976 2 0 5 ~ 414 P~T/A~9ut~ol3~
_ 5 _
only by a maxlmum in ~h~ ord~r of 20 ~o 25~ and ~ommonly
lO to 15~ or le-~s.
The ~dmlxin~ m~ generally be per~ormed at a~blent
S or r~om temperature, but ~here m~y be oircumstances where
lt l~ adv~nt~geous -to mlx a~ elevate~ temper~tures, and
by w~y o~ ex~mple only atten~ion is dir~cte~ to the
pro~ess ~nd product d~s~ibed ln Int~rn~tl~nal Patent
A~pli~tlon WO 87~04145, the content of which i~
lncorporated herein b~ ~e~erenoe, w~ich process and
produ~t m~y be modl~ed ln aocord~nce with the pr~sent
lnve~tlon,
Advant~geou~ly, the magne~ian ~ment i ~ produc~d r
from low ~ost ~r byproduc~ magne~ium o~mpo~ltions, s~ch
bi~terns a~ a ~o~ce o~ magneslum ch~oride and low
~r~d~ m~gne~ite as ~ souroe o~ magnRslum oxlde~ ~it~erns
is the r~sidual liquor ~rom the ~o~trolled evapor~tlon of
~eaw~ter. It m~y n~t 4~ nece~ary to pro~ide addltion~l
~0 wat~r in th~ mi~ture to yl~e th~ slu~ry a w~rkable
~si~enc~ if thq ~urce m~ter~al~ ~ompri~e ~u~ ient
water. I~ the ~agne~ium chloride ~ouree m~terial ls
partlcul~te it ls prefQrably rlnely divldad, wi~h, for
example, a part~ size o~ le~s ~han abou~ 2S0 ml~ron.
I~ ha~ bee~ dl~overed that the u~e o~ ~ low ~od ium
con' en~ bi~ern& with A M~N~ waight r~tlo of gr-3ater
than thr~, pr~e~b~y grea~er than elgh~
par~i~ularly adv~ntageou~ ln ~h~ und~sir~ble
~f~l~re~c~nce ~n ~h~ ~ ul~ant magnQ i~n ce~ent m~y ~e
markedly r~duced.
Wl~h regard to ~he ma~nQ l~m o~id~ ~our~e m~t~lal,
a magnesium carbonat~ min~ral such a~ magnesl~e or
d~lomi~e c~n b~ utlli~ed ~te~ calcln~ion ~t
~uf~lcien~ly low te~peratur~s to provlde ~uf~icient
re3c~ivity in ~he re~ult~nt MgO. M~gnesi~e is pre~erably
5lJBSTlT~JT~ S~IEE-r ~
~,
SENT ~[~IE~ ~ C~LLISON ;.3-10-~1 ; 17:10 ; .~EL~ E~ J~ 1}'~
; WQ ~ 2 0 ~ CTJAU~iwi~
~ 6 -
oalc~ned ~t tempe~ture~ o le~ th~n 4bou~ 820~C to
re~ain ~u~fic~nt 3^ar~ce ~aa a~ re~ctl~ty ~r. th~
p~oduct MgO. Dolomite is prefer~bly p~rt calcined to
rO ~ SgO cln.d cc~lclt_ ~o~oro u~: . Th~J~G ~ cl in Lh~:
art will appreclate th~t other YoIlrc~ of M~O ~h as
~ lned brucite or ~lcin~d m~gne~ium hydroxide, aY C~n
l:~o dorl~d ~r~m cz~wator, or mlx~ Lo ~ Rn~ o th~
~bove, ara alæo sul~able io~ ~ho pr~c~ice o~ ~ho ~rOOGss
of the pre~en~ inv~n~on, Preferably th~ magne~ium oxlde
sourc~ m~te~ial is fl~ly dl~ide~.
A phosphat~c m~terlal Comp~i~in~ ~ a m~Jor portion
oalci~n hydroxypho3phat~ ~nd/or fluorophosphates may be
u~ed in ~he pre~erred ~mbodiment. Such a ~omposition is~
found oc~uring n~tu~lly ln commerci~lly ml~ed phosphate
~sposits ~ubstanti~lly a~ the mlneral ~p~ite, elther
fl~o~8pa~ite Ca5(PO~)3F, hydroxyapatite Ca$~PO~)30H, or
aY a mixed ~luoro-hydroxy deriva~ive. In sediment~ry
depo~its, ~ppreclabl~ sub~titutlon of the pho~ph~e ~y
~0 ~ar~onat~ o~ten ocaur~ in the ~p~tite cry~t~l Y~rUC~re,
to give ~rbonate 8patit~3 ( ~ran~ollte~); the~e also ~e
~ui~abl~ composi~lon~, as are ohloro apati~es.
Another qom~osi~on whlch may be u~ed in th~
pref~rr2d ombod~ment is the w~gte ph~ph~ic mat~rlal
found oa~uring n~turally ~ ~he ~o-~lled "l~a~h~d-zone"
pho~ha~a~ in w~ther~d edimen~ary phosphat~ depo3ltY at
loc~tlon~ lnal~dlng ~lorlda (USA), Sen~gal (W2~ Afrl~a)
and Chri~tma~ Islan~ I Indi~n Oc~ . Thi~ ph~ph~te,
often a mlxture of ~pa~e a~d ~y~oxyph~pha~e ~in~als
such ~s crand~llit~ and ~ e, is a low ~rad~ ore
w~lch ~annot ~t. pr~n~ be economically co~verted to
oth~r us~ul prvdu~ts.
Pr~acidulation o~ ~he in~ le ph~sph~tic material,
elther p~r~ia~ly or ~holly, is adv~nt~geously p2~0rmed
uqin~ ph4~phorl~ d, ~ulphurlc acid or a combina~ion of
SU~STITU~E ~ E~
SE~T BY:DAVIES & COLLIS0~ ;.3-10-~1 ; 16:i7 : ~EL~()L~E~lfj ~fil ~0~0
. ~ V0 ~JI1~7~ 2 0 ~ 1 4 1 4 PCT/AU9~/~132
-- 7 --
the two. U~ of p~osp~oric a~id to a~tivate the
ln~oluble phosph~tlc material can beneficially provlde
water resi~an~e and me~hanical ~xeng~h superior or
~ub~tan~i~lly equlvalent to -that achleved ~ g ~ greater
~mount of phosphorlc acid alone, without the presence of
the insoluble phoæphatlc material~ Us~ of sulphurlc acid
to preacidulate the insoluble ph~phatic m~teri~l
p~vldes water re~ist~nce and ~echanical prOper~iQS
ess~ntially equlvalent to th~t obt lned using pho~phoric
acid, ben~fi~i~lly ~llowlng total replacemen~ of
expen~ive p~osphorlc ~cld by much ~haaper ~u~phurio acld.
Al~ern~t~ ~ely, the pho~phatlc ~terial in the
mlx~ure may not be prea~idula~ed ~ specified in the r
lmmediately pr~cedins paragrap~ ~ut acidulated at a later
stage w~en the phosphatia component is al~ead~ bound
wit~in ~he ~et c~me~tl~ious ~atrix, whereby the ~ment i~
imm~rYed ~ie~ly ln ~n ac~idic: :3o~ ution ~ at least
p~rtlally aoidulats th~t pllo~ph~tic mineral component
2~ wlthin, or at l~a~;t clo~e tc~ the l3urf~e of, th~3
oem~nti~ious obJec:t. Exan~ples o~ appropriate ~cid
olutions are phc~3phoric acld ~nd ~ulphuri~ ~cid.
In another embodi~ t o~ ~he pr~3sent inYen~ on, the
25 pre- or post- ~cld~latl~n c:~ the in~olu~le phc~ph~te
mineraL component to provi~e ~ r.ementi~ous produc:t o~
increa~ed wa~r re~stance is c:a~ri~d out af~e~ mildly
p~alcinin~ the in~olu~le ph~sph~tic componen~ prior ~o
mlxinSI wlth the o~h~r ~emen~ componant~. SuC:h
30 pr~ alcinlng may ~ pe~formed at temper~ 4ures in thf~
ran~e of, for ~ mple, 300 ~o 700C, p~fe~ly 4$0 to
550S;~ for ~pto ~hout 3 hours~ Whore th~ insoluble
phosphatlc ~:omponent compriE3q~, :Eor examp~, crystalline
calcium ~lumlnium ~ydroxyphosph~eg ~iuch z~; cr~ndallite
35 and milli lte ~ in ~h~- a~orem~ntloned low grade ores,
c~alcination for in~t~nce ~ soo~c wi~4h a r~ention t1me
of one hour h~ been found ~f lcient to dest~oy the
SENT ~Y:~AVIES & COLLISON ; 3~ g1 , 17~ ELBOLR~E~ D0 :~17/ifJ
~VC~gO/11976 2 0 5 ~ 4 1 4 Pt~r~A Vg0JOD13
- 8 -
miner~l cr~y~Italllnity~ con~e~tin~ the mlneral pha~es to
more rea~tive amor~hous struqture. T~iS pre~alcining
step b~n~fitQ tha u~ of acld~ ~uch R~ ~ydrochloric and
ci~lc ln the acldu~a~ion step, aclds in whlch ~lclum
aluminium hyd~oxyphosphate minerals ~uch a~ crand~llite
~nd m~ lte are ~ ti~ely insolu~le unle~ mlldly
cal~lned to de~oy ~heir cry~t~llinlty~
In aotiya~ing ~he pho~ph~lc mlneral by ac~dulation,
lt i~ ~re~err~d to Dnly p~rtlall~ ~aldulate, especlally
when si~nlfl~nt aluminous pho~ph~ts 1~ prq~ant. A~ th~
op~l~um degree o~ ac~dulat~ On dap~nd~ i~ part on ~he
~bsolute amount ~nd ~ompo~ltion of the phosphate
inoorporated o~ ~o ~ in~orpora~ed in the cem~nt, the
nature o~ th~ acld u~ed ~nd ~hP de~e of pho~phate
precalcln~tisn, i~ ~ny, 1~ mu~t ~e det~rmlned ~y trial
and ~xp~riment. Complete acldul~tion ~nd ~olubi~ iza~ion
of ~he ph~phat~ of~en conler~ no ~ddltional ~efit ~nd
may ln ~act be detr~mental to ç~m~nt propertle~,
~0 ln~luding t~ak of w~r ra~i~t~nce. Acldulation ~i~es
will c~nunonly ~e f~om 1 to 60 mlnu~e~, pr~fer~ly from 4
t~ ~0 minut~, mos~ pre~rably about 15 minute~. ~h~
amo~n~ o a~ld ~ppropri~ ur th~ acidul~ti~
dep~n~ent upon the ~mo~nt of re~ctive ~gO in th~ mlxture
25 and wlll gene~ally be upto ~bo~t 20g ~er 100~ MgO.
T~ble l ~pre3ent.~ advsnt~ous op~r~tt ny p~rama~ers
and vari~ble3 whl~h ~r~ pre~ntly considersd appr~pri~e
fo~ the m~gne~an c~me~t prod~tion proces~ u~ln~
~0 Chri~tm~ Isl~d miner~ pho~phatio material
preac~dulated with pho~phor~ acid or ~ulph~ria ~cld and
wi~h option~l pr~cal~ination of ~he phosphatic. ma~arlal.
SlJ~ST3~ S~
SENT By DAVIES ~ COLLISON . 3-10-~1; 17:12 : ~ELBOL~R~E~416 ~ 0 9O/11 l976 2 0 3 1 4 1 4 P~IAU~4f ~013
_ g _
q`ABLE 1
Proc::q~ onditlons and Opqra~ins~ Preferr~d
Par~met~rs ~an~e Range
P205 con~nt
( wel~ht percent ) 10-3~ 25-3B
Feed size (micron) <25~ c125
PI~e~cidulation ~C:id
gtlOog MgO ):
Phq3phoric: ~c:~d 1-~0 ~-6
Sulph~ric aaid 1 7C~ 10 ~-8
15 Pre21cidula~ion dur~tlon
( mlnu~e~ 60 ~_~o
~0 Ca~ cin~lon tempera~ure ( C~ 300-~50 400-600
Calcination dur~ion (~inute-~ Q~l-l80 15-60
MgO/M~C12 stoinh~ome~ry,
mole~3 4-l2 ~-8
P~o~3phati¢ mineral com~onent
)C)g MgO ) 2-lOo S-~5
Fe~d ~iz~, MgO (mi~ron~ c250 ~90
Su~fac~ a~e~, M~O ~m ~) 5-~0 ~5-60
M61/Na wei~ht ra~lo, bi~t~3rn~3 ~3 ~8
( wh~le ~ppllczlble )
By op~rating wlthin th6~s~ ~ramete~ he
35 ~toichiometry c~f the proce~ controll~d to pro~ de as
~ m~Jor ~rye~t~lline csment~tious pha~e orm~d in the
h~rd~n~3d cem~nt th63 m~nesium oxychlc~rid~ hydrate
~U33 ITUTc S~
SENT BY:DAVIES ~ ~OLLISON ..3-1~-g1 ; 17:12 : ~EL~O-R~E~ a~ o
`, ~OgO~1i97~ 2 0 51 ~ 1 ~ YCT~AU~0023
- 10 -
comp~nd 5Mg~OH~.MgCl2.~0.
I~ all em~diments t additlve~ ~nd fillsrs may ~e
lncorp~rated into the c~mentitiou~ mix prlor to setting
S to inor~ase wat~r resl~tanae and/or mechanlcal stren~th,
to provide s~itable c~lourln~ or texture, to control
shrlnka~e or expan~ion, to ~on~rol the r~eolo~lcal
prop~rti~s o~ ~he ~em~ntitlo~ ~lurry, or ~imply ~o act
~s inert ex-tend~r ~uch ~ddi~lves whloh mlght be u~ed
~O incl~d~, but ar~ not lim~ted to, i~organi~ and organic
fibres, piyments, lignlns, lignosulphonate~, s~rfactant~
an~ foam promot~rs, ~uperpl~Rticl~ers, sawd~s~,
woodchlps, ba~asse, ri~e hull~, ~la~s, flyash, tal~,
slllca ~and, clay~ and o~he~ ~lu~lnosillc~te~. It ha~ r
lS bee~ found of partiaular ~lu~ to incorpo~ate ~llica fume
or ml~r~Rilica in thP oemontitiou~ mix ~o further promot~
w~t~r reslstance in the h~rdened c~ment. In all
embodiments, th~ ma~ne~ium chloride ~urce m~erial ~ay
be repla~ed wholly o~ in pa~t b~ ~ m~n~slu~ ~ulphate
~urce mat~rial suqh as epsomlt~
The magnesi~n ~m2nti~10~ ~ompoæitio~ of the
pre~ent invention may h~ve wide appli~abill~ in the
buildlng and other indus~ie~, ~nd may hen~lcially ~e
~5 incorpor~t~d in many p~ducts includin~ foamed in~lation
panels an~ co~ln~s ~nd ah ~ binder in parti¢le- ~nd
hard-bo~d ~ompo~ltions.
EXA~P~
The ~ollowin~ example~ are given by w~ o~
illust:r~tion ~nd no-t by way oi~ nlt~tion ~31nc;e ~r~ri~
ah~nyes ~herein m~y he made by ~hose skill~d ln the ar~
w~hout d~p~rtln~ Erom ~he tru~ ~pirlt and scope ~ the
~5 pr~nt i~vention~ Un~e~ st~d other~i~e, ~hristm~s
Island p~a~ph~te rock compri ing a mlxture of calcium
alumlnium hydroxyphosphat~ mine~ nd apatit~ was used
$13~5TIT13TE S~.~E~
SE.;~IT ~Y:DAVIES ~ ~OLLISON ; ,3-10-~1; 17:13; ,~ELBOI~R~E~ 0 .X~
...
o sotals7~ 2 ~ 414 P~AU~0~00132
in the Examples, ground to 12~ mlcron~3 or le~f~. The ~CIe
of ~ gne~lum ~hlorid~ hexa~ydr~t~ sintul~ted ~he
incorporation of l:~itterns ln the process.
5 EXA~ 1
A C:elnent~ ~iou~ slurry w~s p:~ap~red by mixlng 125
part~ o~ Low ç;lrade ~loln~d Inagn~ e, oontalnin~ 100
par~s of M~O, wl~h 78 part~ of magneY~um chloride
10 hexahy~l~a~e plus 35 part~ of ~dded water. Th~ nesite
u~e~, from Copley, South Australla~ was finely ~round
after calcsin~tlon at ah~u~ 810~C to pa~;s gO m~ ons and
posse~ æd a surf~ce area o~ about 50 m2~ after
calcir~a~ion~
lS
In ~ serie~ o~ statlstically de~ n~d exp~3rlmellts
uslng such prepar~tions, it w~ found that additiorl to
the alkaline cem~ntitious ~lurry Of ~ . 3 parts ~alcined
Chri~tmas Island ~ rade phosphate ~ock ( 31 wt . ~ P205 )
20 wa signifiaant~ ( at tha ~ onfide!nae la~el ~ at
decr~aasing t:he water sol~bllity of the re~ultant ha:rdened
~em~nt to 25 . 7 ~ when c:omp~ed to oontrol prepa~tlons
cc~n~a~ ni~s~ no ~ch Christmas Island pho~phate rock, th~se
cc~nt~ols ~hibltin~ 2~n ab-~olu~e water solubillt~ of ~7 . O
25 % as h~rdened C:ement-r~ contr;~s~, ~3ddition o the
Chriæ~ nd pho~phate when 1 n an unc~ in -d ~tate
provlded no ~nhanc:~em~nt to ~e water résls~ance
~hat~o~3v~r. The solubllity te~t compris~3d i~ 3rsing
~mall qample,s of ~he har~len~d a~meF~ts in ~p w~e~
30 (Adelald~, South Au~tralia~ for 17 hours at ~UC, this
tr~tmç!r~t satlsf~ctorily s~ mul21~lng lon~ term water
i~uner~ion a~ ambient ~emperatur~. The c:alolna~ion
trea~ment of th~ C~h~lstmas I~l~nd ph~sph~ comprised
hoa~lng the ~o~k in ~ muf~l~ fu~n~ce fc~r one ho~r at
- 5Q0C, ~r~3by the cry~lllnity o~ ~he major alulninou~
pho~phate ~inera~ ~ in the rock, namely ~r;~ndallite ~nd
milli~ite, is destroy~d r ~onv~rting the ~lumlnou~
______
E S.;~
SE~T BY:DAVIES & COLLISON ; 3-10-~1 ; 17:14 ; ~ELB~UR,~E~g1~ g~ GO ;~lJ~
O ~0/11~76 2 ~ PC~rJAUgO/~132
- 12 -
pho~pha~e ~ more reactive amorphous form~.
~XAJ~PLE '~
S In a first cement preparA~ion, ~n acidul~ted ~lurry
w~s prepared from l~7 parts o~ Christ~as I~l~n~ C-grade
phosphate ~ock (25.~ wt. % P205~ and 4.2 par~ of
phos~horfe ~cld~ Water was add~d (3 pdrts) to maln~ain a
sati~a~ory ~on~l~tenc~ and prevent the mlxture rom
becomln~ too thi~k~ ~he acidul ated m1xture w~s l~ft ~or
l5 mlnutes with occasional ~tirring . CalclnQd Copley
m~gne~lte (l2~ par~ ~ontaining lOO pa~t~ M~O), magnesl~m
chloridq hexahyd~ate (7~ part.~) ~nd further w~ter (32
p~rts ? were next add~d to the slurr~. After ~tirring,
the ~ementit$~us ~lurry ~as po~ed ln~o moLds and allowed
to ~et.
Two ~ur~r pr~pa~ions ~ere m~de ln a ~imil~r
m~nner ~ithout ad~it~on of Chri~tma~ Isl~nd phosphate
mixin~ 125 part~ of ~alclned Copley m~n~æite, 78 parts
of ~a~neYlum q~lori~ ~exahydr~t~ and 35 part~ o~ w~ter.
To one o~ ~h~se ~urther preparations, 7 par~ of
p~osphoric ~c$d W~Q addition~lly in~or~orat~
2~ After ~llowln~ ~o h~rde~ ~or ~t lea~t 15 daya, the
c~ments fr~m all thLre~ pr~p~a~ion~, ~n ~h~ form of 2 cm
~ube~, w~r~ ~bjected to compr Y~i~e .~ren~th t~sting and
d~ezmin~tion ~f w~t~ r~sl-~tan~e by ~he æolu~llity tes~
~t ~0~ speoifl~d in ~xample l.
~0
A sample ~ro~ that E;~rf~p~r~tlon cs~nt~ining no
C:hristmas I~l~nd pho-~phat63 and no pho~phoric ~3cid showad
~ c:ompr~sslv~a ~trenslth of 50 MPa with no wa~er ~eat~nen~,
but wat~3r ~rea~m~nt ~t 8C) ~ ~ cau~d an identical sample
3S fro~ the prepar~ion to experience alm~Yt tot~l
di in~gr~io~, with an accomp~nylng weight l~s ~f 3Q ~.
SlJBST~'JTE ~r~:;E~i
___
~ENT BY:DAVIES & COLLISON : ,3-1~-gl : 17:14 : ~EL~OLR~E~ g61 ~000 ~22/~fJ
`~0 90/llg7~ P~r/AUg~/00132
- 13 -
A ~mple ~rom the p~epar~tlon ~o~t~ining no
~rl~a~ I31and phosph~te but con~ainlng 7 p~rts of
phosphorl~ ~id ~h~wed ~ oompres~l~e ~tren~th of 37 MPa
with no prio~ w~tex treatm~nt, while a s~mple from the
5 ~ame p~ep~ratlon after the 80~C water treatment exhlbited
a compresYlve qtren~th o~ 23 MPa and ~ water solubility
o~ 5.5 ~.
For sample~ from the prepa~tlon con~alnin~ ~oth
10 Ch~ s l~lan~ pho~ph~te ~n~ pho~phorl~ acid, a
compr~s~lve Ytrength of 3~ MPa was obtain~d ~ith n~ prio~
wa~r treatn~ent and a value o~ 30 MPa with an ~s~aiated
~ater solu~ility o~ 5.0 ~ or an identical sample
s~b~acted to the ~0C water ~reatment.
This example demonstra~es that pre~ence of
pho~pho~io ~cid, when contr~ted to ltq a~e~cP, provides
high strength re~ntion ~nd low ~olubility for hardened
cements after a S~vere water treatme~t. This ex~mple
2Q unexp~te~ly demonstrate~ fur~her ~at pre~ence o~
i~ol~ls pho~ph~tic ~.inerals ~f~er p~rti~l
pre~c~dul~tion wlth p~o~p~ori~ ac~ is benefi~ial in that
lt c~n p~ov~de gre~sr or equi~al~nt ~rangth retenti~n
after water trea~men~ than does u~ of a gr~ater amount
25 of phosphoric a~id a~on~. By contr~stlng with Exampl~ 1,
the pr~e~t e~ampl~ also dem~nstrates by the comp~rati~e
w~ter ~ol~bilitl~ of ~h~ ~emen~Q that use of the
pr~ ulat~n ~tep for th~ ol~le pho ph~e is
~uperlo-r to ux~ of ln~oluble p~osph~t~ wi~hout
30 p~ea~ldu1ation.
XA~PLE 3
An ac:idtllated slurr~ wa.~ p;repared from 1~.7 pa~t~ of
l~llristma~ I3~ and C-gr~de phosph~te rock ~?~$.2 wt. ~6 P205)
and 6.3 part~ o~ 7~ lph~ic a~id. Suffi~ient ~ater
was added ~6 parts) to pre~rer~ h~ mixture from l:~ecoining
C~STITL3T~ S~ ~E~
SENT LY:DAYIES ~ COLLISON ; ,3-10-~1; 17:1~; ~lELBOLR~iE~ 61 ;OO~ :i2.,~
--- ~o g~fll~76 PCrtAU~0~132
2 ~
- 14 -
too thl~X. ~he ~id~ated mixture w~ lef~ or 15
ml~utes with oc~a~ l s~irrlng. C~lclned Copley
magn~site (125 pa~t~ containing lOO parts M~O), magnesium
chlorlde hexahydr~te ( 7a part~ ~nd furth~r ~ater (36
p~rts) were next added to the slurry~ After ~tirring,
the cementitious ~lurry wa~ pourBd into moldR snd allo~ed
to ~et. I'e3ts performq~ on the h~rdened ~ements were
ldentl~al to tho~e ~peci~ied for Exampl~ ~.
A compre5sive ~tren~th ln ~xce~Y of 54 MP~ wa~
~xhl~lt~d by a 2 ~m ~ube of this o~ment with no water
tr~atment, whi~e a ~ater tre~te~ sample (as before at
~~) po~ses~d a ~ompre~ive ~rengkh of ~1 MPa aft~r
assoclated dl~olutlon o the qampl~ ing the water r
~reatment of 7.3 ~.
Thi~ ex~ple illust~tes a fuxther aspect of the
pref~rred embo~im~nt of ~he present invention. It
unexpectedly de~ons~ra~e~ tha~ d~plte the hlgher w~er
2U ~ol~bllity (compa~ed to tho~e ce~ent ~mpl~ ln ~xample 2
~ontal~ln~ ph~phorl~ ~Cld~ prob~bly due ~o leachln~ of
the calclum ~ulphate ~orm&d, ~ hi~h ~ ng~h is retain~d
a~ter water treatm~nt, compar~le to th~t wa~er t~Q~ed
sample in Example ~ wherein pho~phoric ~c~ was u~ed
~lon~ without mineral phosph~tP ~d~l~ion~ The pr~nt
ex~mple Xur~.her d~ons~ra~s ~hat for equival nt water
re~ t~n~e ~ quantifle~ b~ comp~es~lv~ ~reng~h
reten~ion i~ th~ ~ured ~ment, ~ulphur~c a~d, whe~ ~ed
ln con~unction with an lnsolubl~ pho3ph~ min~r~l
component, can beneficially rep~ce the mor~ ~xpe~sive
phosphorlc acid u~ed alone.
EXAMPLE 4
3S Three s~ries of C~menk~ w~r~ prepared in thls
ex~mple. All ~em~nt composition~ were id~nti~al except
~o~ the pho~phate compone~t, ~nd ~ ~llgh-tly ~aryi~g w~ter
SU~5Tl ru ~ ~ S~
SENT BY:DAVIES & COLLISON ; 3-10-g1 ; 17~ ELE~LR~E ~lf ~1 'JO~ 2
- ` W O 90/11~76 2 ~ P~rIA ~90/~013
- 15 -
~o~tent t~ provide a ~uitable conaiatenoy du~ng mixln~,
In on~ serles, ~i~fer1ng amount-c of phosphori~ ~cid were
added~ In the other two ~erles a constant amount of
~hrlstmas Icl~nd C ~r~de phosph~te ro~k was added
5 togeth~r with di~erlng ~m~unt~ o~ phosphori~ acid (the
second serle~) an~ sulphu~ic ~cld ~thlrd serle~). All
cemen~s al~o cont~lned ~ a ~L~ne. ~he lOO part~ of MgO
used ~ ea~h formulation ~as contained in 125 p~rts
~alc;.ned ~pley ~gneslte.
~n the ~ir t ~eri~ a pr~lx w~s prep~rsd by
addltion o~ 29.4 parts M~O to 30 6 part~ water followed
by selected addltions of pho~phoriq ~cld ~a~ ~lven in
Tabl~ 2~ ~he premlx was lef~ to ~tand for lS minutes
lS aft~r w~ich 69 p~rts MgCl2.~H20 w~s added foiiowe~ by the
~lnal 70.6 p~rts M~O premi~ed with 3.7 p~rt~ silica fume.
In the ~ec~n~ and ~ird -qerl~s, h~lected addi~lons
of phosphoric ~ and su7phuric acid, r~spectl~ly, ~s
~0 det~ileq in T~ble 2, werQ ~dded ~o 14~7 par~ uncalcin~d
phosphate rock followed b~ a Qm~ll amount of w~ter lf the
m~tur~ wa~ dry~ ~he ~remix was l~ft ~o Qtand ~or 15
mlnu~s after wh1~ 3a part~ w~ter was ~dde~ followed b~
2~ p~rts MgO. T~1~ was l~ft ~o stand ~or 5 mlnutes.
25 At t~ poln~ ~ pa~s ~gCl~.6H~O wa~ a~ed, followe~ by
3.7 par~ lca ~um~ pre~i~d wlth 7~.6 p~rts M~O.
W~t~. ~lu~ilitie~ were d~r~nine~ ~t BOC ~y the
m~hod giv~n ~n E~ample l~ R~ults ~r~ ~hown in Table ~.
~0
The dat~ in Tabl~ 2 demon~trates tha~ the wa~r
ssl~billty fo~ ~ement~ contalning ~dula~ed ro~k
phosphate g~s ~hroug~ a mln~um ~lth ~ optimu~ ~mount
o~ a~id (fo~ bath pho~pho~lo and ~ulphurio ~ids) ~t
35 ~bo~ 5.5 p~t~ with the G~mposi~lons u ed i~ this
Example. Highe~ amounts of ~¢ld und~r these oonditions
are detrlm~n~al, de~r~ing ~hç wate~ re~ista~ce.
SIJ~STITUT~ S~
_____
sEN/r BY:DAVIES & COLLISON : 3-1O-gl . 17:16: ~ELEOL~;E~ 000 ;~
~~ ~0 90/1197~ 2 0 ~141~ P~/AU~O/D013~
Solubllltie wi~h ~ulphuric ~cld are h~ e~ th~n those
wlth phosphorlc aqid, ln part, at le~st, flue to the
~orm~tion of appre~i~bly soluble c~lcium ~ulph~e wlth
th~ forlner.
It ls further beneficl~lly demonstrated t ~s in
Example 2 ~ that the d~rea of wate~ r~3~lst~nce ilnparted
by pho~phoric ~ alone can ~ m~tc::h8d by ~
slgnif lc~ntly lowe~ amount c)f pho~phorlc: acld i~ used in
c:ombina~lon wl~h rock phosph~te. For axample, wa~er
re~ tanc~ ~c;hl~3ved by 7, 4 p~srts phc~sphoric~ acid 1~;
~gualled by u~ing orlly about 2 . 8 part~; o phosE~ho:L ia
ln com~ination with 14. 7 p~rt~ rock p}~osphate addition.
Sili~a ~um~a es~~ cQs the water reSi~tE~rlCe of ~he
c:ement~ . ~ 2~ weight ~ OB~ found wi~h sillca fume
addl~ n ~ut with no pho~phate is lc~wer than the ~8%
found in ~:~ntrol c~3ment~. The benefl~ial ~fet:t of
slliG~l f~ne it3 malntalned in pl~osph~-te contairling
cem~n~, w-~ th t~ w~Lr res;~tance ~ontrl4ution~
appar~3ntly ~u~stantial3.y ~ddltlve a~ se~3n by ~c~mpar~ ng
the ~ter ~o~bility da~a of thi~; E~ample wi~h ~xamples 2
~nd 3
TAE3~LE ~
Amount of ~ci~ A~ . and ~orre~ndinc~ $o~ ubill~ __ _
50lubll~y ~ w~ight lo~, p~r~ent
. ~ ~ ..
Amourlt of Acld Ser~e~: 1 ~ .~
( part~/100 p~ Mç~0 ) Phosp}L~ric:R~clc Pho~ph~te '~ k phosphate
Ac~id Alone~ phos ~cld ~ sulphl-rlc
0 21.~ 2~.8 ~Z.0
Q.g 8.5 5.~ 10.6
l.8 5.2 3.D ~.6
2.8 5.~ 2.6 7.0
3.7 3.5 1.9 4.5
5.~ 2.7 l.~ 4.0
7.4 ~.~ 1.7 4.7
~V~ E
SENT BY DAVIES ~ (:OLLISON ; .3~ 1; 17:17; .~iELE~O~ 'E~41~ 0~
~ ~/1 i~76 2 0 ~ ~ 414 PC~/hU~/01113~
17
~,~
~wo type~ of c~nen~ ware prep~red from tha hlgh
S gr~de cal;;lne~ m~gne~lts from Kunwa~ara, Queensl~nd: a
water reRl~nt cement oontaining ~aAd, r~ck phosphate
an~ pho~phoric a ::id and a c:ontrol ~ement containll-y no
additive ot~er than s~nd
For t}~ pho~ph~te Inodi~ied c~ment, ~ dry mlx was
prepar~d ~ronl 1170 Çl ~ flnely g~ound KunwE~rar~ calcine~
magn~sit~ alcln~d ~00 ~; free Mg0 9~ . 5 wt . ~ ) and 5 ky
4~ dry ~3harp guallty ~lldln~ ~and ln a mlxer of
conunerc:l~l deYlgn. A ~remlx wa~ separat~ly pr~pared by,
15 addins~ 50 51 phosphoric acld ~o ~ ~lurry c: f 200 g
Chrlstma~ land C s~rade phospha~e rock and lt~0 ml wat~r.
A~ter 15 mlnute~ 130 S~ of Runwarar~ c~lc~ ned Inagr~3site
was add~ad to the pho!3ph~te premlx wlt}l ~lrring. l'his
mlxtur~ ~orm~d ~ dry m~x ~nd wA~ ~ubsequantly slurrled
~0 l~7ith an<: ther 100 ml of water, and w~h~d into the ~gO-
~and dry mix with 1~0~ ~nl of magne~ium chlor$d~ ~olution
( densi~y 1. 30, 3~ ~ MgC1~ ) . Mini ~al ~ddltlonal water ~as
added wh~re nec~ ry to maitltain ~at~ tor~
cor3sis~tency in the cem~n~ ~21urr~r. The cement c~l~rry was
25 poured lnt~ 10 ~m cu~ molds, wl~ vibr~iny ~o r~duce
p~oslty .
A contr~1 o~m~nt w~.Y ~imilarly pr~3pared by m~klnSr a
d~ mlx o~ 130~ g ~Cunwarar~ c~lclne~ rnagn~ e ~nd S k
30 of ~ry sand. ~o this mlx WBs ~dde~ 1000 ml of ~he same
magr~e~ium ¢hlorlde ~30lutiQn~ Additional w~er waq ~dded
to the slllrr~ r~quired~
Th~ phc~gph~3 modii~d ::~m~n~c exhibi~ed cvmpr~ssive
3 5 ~trength~ in ~h~ dry ~t~t~: of a~out 5g t Z MPa .
Corre~pondin~ ~ompre~lve~ ~3trqngth~ af~e~ immer~iion in
tap water al: ~oom ternper~ture for 7 and 30 d~ys were
SU~ 5T~
___
SENT ~Y:DAVIES & COLLIS~N :.3~ 17:17 ; ~ELBO~R~'E~ 0~ 7/4fj
~- NOgO/1l976 ~ PCTJA~0/~132
- 18 -
~ti~l high, at 42 ~nd 4~ MP~ reBpectlvely. A wet/dry
cycl~c test a-t amblent tempe~at~re, consis~ing o~ ~
cyoles o~ one day ln freæh tap wa~er followed by two days
stored ln alr, re~ulted ln a c~pre~i~e strength ln a lO
cm cube o~ 57 MPa, practically unchan~ed from that for
continued storage in ~lr. The ~elatlvely sm~ hange ln
~mpr~sl~e refleck~ the minimal solubllity o~ the
samples noted du~ing the tqsts.
For ~ubes o~ ~he ~ontrol c~en~ cont~inln~ no
pho~ph~te, typical compres~ive stren~ths ~or dry ~toraga
reached g~ MPa. However for id~n~lcal water i~mersion
and a~ c t~tin~ dnne for the phoRphate modified
cem~nt, the cont~ol cubes d$Yinteyr~ted; no ~om~res~l~e
15 s~rength te~tiny wa~ po~ible.
~ example demon~*rate3 a novel method of
ln~orporating ~he a~dulated pho~ph~t~ ln the 4~ment,
where~ the phos~hate ~lurry ~ onverte~ to a ~lne dry
20 powder by premixln~ ~he s~ur~ h a por~i~n af the ~gO
used in the ~emen~. ~hi~ ~y pre~ix ls ~ conv~nlent w~y
Qf ~torlng the acid~l~ted ph~spha~e ~nd allows i~ to be
added to th~ c~ment mlx at a convenle~t later timer ~he
dry prem~ ould a~o b~ zldd~d hack sqith ~h~ remainder o~
25 th~ M~0, for later mixing wlth ~he m~ne~ium ~h~oride.
E ~
A ~er~ f c~me~ts were prep~red with ~hrist~as
30 Island Grade ~ phospha~e r~ck ~om ~hich ~ll the ~pa~itic
phospha~e component had ~en r~moved. Th~ ~ps~lte ~a~
removed ~y rep~ting l~aching o~ -the ~o~k wlth 2.5 molar
hy~ro~hlorl~ acid ~olution, wh~le monitorin~ the lea~h
proCe~ pr~duct~ by X-ray d1ffra tion ~naly~l~. The X-
35 ray difra~ti~n ~n~ly~is showed that ~ll apa~ite
origln~lly ~re~ent ha~ been remove~ and th~t the maJor
arystalllne pha~e~ pre ent in the le~h~d rock w~re the
S~J~S ~ ~u'r~ S~JEET
SENT BY:DAVIES ~ COLLISO~I ; 3-10-~1; 17:18; ~EL~OIjR~E~ 0~0 .~2
--~O ~ t~76 2 ~ 4L P~/A~1~/~13~
-- 19 --
~ lclum alumlniu~ hydroxy~ho~phates, cr~ndalllte and
mlll ~ site, the~ had remalned undissolvRd ln the leaching
~tep .
t~sln~ a factorially ~esigned s~rles o~ cemen~, half
of th~ s2ample~ pr~pared lncorpor~ted th1 ~ leached
pho~3phate ln the pr~sa~lcined ~tat~; the remalning Yamples
lnc:orpor~t~ th~ le~ched pho ph~te ln an uncAlcined
~t~te. Tl~e cal~::ining step lls~d a one hc3ur therm~l
tr~atmfant ~t 5~0C in ~ muffle ftlrn~c:e. Ju~t p~ior to
~nc:orp~ratinSI in the clsm~n~, ~he e~r~::ted pho~3ph~te rock
was ~o~ dulated with either concentra~d hydrochlor~o or
709~ ~ulphurl~ t ds for period~ rangln~ ;~rom S to lO
minutes. Th~ acidula~ed p~osphate w~ thsn mixed with
125 par'cs of finely ~round c:alcine~ Copley ma~nE~Slt~
(~ontalning lO~ pa~ free MgO~, 63 p~r~ of MgC12.6~120
and ahout 42 p~rt~ w~ter. The ~mou~ts of extr~cted
p~o~pha~e rc~:k and of a~id u~;~d w~s ~ystematl~ally ~arled
to be 12. 5 o:r ~5 pa~t~3~100 part~ ~r~e M~O ~nd 4. Z or l~ ~ S
20 p~rt~/lOO part~ ~ree M~O, :~esp~ctivel~.
Water ~olu~illty te~t~ were m~de ~ ~o n C ( 8S
dç~t~iled in Ex;smple 1 ) c:n th~ ment~ aft~r one wee~
m~turatlon an~ a~airl anoth~r six weeks later. ~o
25 sl~nlficant dlf~i3rence~ wex~ ob~er~Pd in th~ two sets o~
solllblll~y m~a~ur*nlen~-~ m~le ~t dif~erent times.
q'he s~lubili~y d~ta showed that w~ter ~olu~llity w~s
low lf ~al~in~d leached pho~phate :ro~k was u~d in ~he
O ~ement, ~ver~lng 4. 6~ ~d 4. S~ weight lo~s for
hydrochloric ~nd sulph~rio æl :1, re~pec:ti~el~, a~
~idula~ing ~gen~ owever, wh~n u~in6~ un~ ined
leac:hed pho phate rock, th~ c: orre~pondlng averaSae w~lght
lo~e~; wer . muc:h hi~her, a~ 18 . 7 and 13 . 4~ sp~ctl~
35 Thl~; comp~res3 to the 2~ 30~ ~ight lo~ xperienc:ed in
control a~nts wlth no phos~h2te a~ ion.
SV3S~lTU~c S~E,
SENT 13Y:DAVIES & COLLISON ; 3-lQ-~1; 17 1~ ELB~L~;E~l~ g~ 0~ ;~2~
W~ g76 2 ~ P~r/AU~UJ~3~
- 20 ~
These r~ult~ demonstrate t~t if the r~adlly a~ld
soluble ~patlte ~calclum pho~phate~ impurlt~ is removed,
~he calclu~ aluminium hydroxyphosphate minerals remalning
~u~t be actlva~ed by ~alcinatlon prior to ~cldulation -to
o~taln minimal water ~olubllity and maxlmum water
r2sl~tan~e in th~ cement. Cal~ina-tion converts the
~ystalli~e h~droxypho~phate to a more a~id ~oluble
am~phous ~t~te. Consider~bl~ less water resl$tance ls
impart~d ~o the ~e~qn~ by the calcl~m alumlnium
hy~roxyphosphate component lf un~al~ined; the reYults
d~monstrate ~ha~ h~drochloric a~id i~ leYs ef~ectt~e with
thQ un~alcined pho~ph~e ln thl~ inst~nce ~han is
sulph~i~ 8cid.
lS ~ho~e s~illad in ~he art will appreclate that the
lnventi~n deY~rlbe~ herein i~ susceptl~le to vari~tions
~nd mo~ificati~n~ other ~han ~ho~e specific~lly
des~rlbed. It i~ to be unde~stood ~hat the invel~tlon
in~ludeY all s~h ~ri~tlons and modlfi~ation~ which fall
withln the lta spirit ~nd ~cope. The lnven~lon also
incl~des ~11 o~ the step~, featur4s, oomposltions ~nd
oompounds r~ferred to or i~dl~ated ln ~his ~pec~ atlon,
~dividually or ~ollectlvely, and a~y and all
com~inations of any t~o or mo~e ~f said ~t~ps or
~eature~.
SUI~T~TUTc S~EE 1-
