CA2051414A1 - Process for forming water resistant magnesian cement introduction - Google Patents
Process for forming water resistant magnesian cement introductionInfo
- Publication number
- CA2051414A1 CA2051414A1 CA 2051414 CA2051414A CA2051414A1 CA 2051414 A1 CA2051414 A1 CA 2051414A1 CA 2051414 CA2051414 CA 2051414 CA 2051414 A CA2051414 A CA 2051414A CA 2051414 A1 CA2051414 A1 CA 2051414A1
- Authority
- CA
- Canada
- Prior art keywords
- magnesium
- process according
- source material
- phosphatic
- mineral material
- 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.)
- Abandoned
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
- C04B28/30—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing magnesium cements or similar cements
- C04B28/32—Magnesium oxychloride cements, e.g. Sorel cement
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B22/00—Use of inorganic materials as active ingredients for mortars, concrete or artificial stone, e.g. accelerators, shrinkage compensating agents
- C04B22/08—Acids or salts thereof
- C04B22/16—Acids or salts thereof containing phosphorus in the anion, e.g. phosphates
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
- C04B28/30—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing magnesium cements or similar cements
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
- C04B28/34—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing cold phosphate binders
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/20—Resistance against chemical, physical or biological attack
- C04B2111/27—Water resistance, i.e. waterproof or water-repellent materials
Abstract
ABSTRACT OF THE DISCLOSURE
A process for the formation of magnesian cement having low water solubility and long term retention of mechanical properties. The process comprises acidulating insoluble basic, hydroxy and/or fluorophosphatic mineral material to activate it prior to or after mixing the mineral material with reactive magnesium oxide source material such as calcined dolomite or calcined magnesite, source material for magnesium chloride and/or sulphate such as bitterns, magnesium chloride hexahydrate or epsomite and sufficient water to make a workable slurry, with or without other common additives. The mineral material may be in the form of low grade phosphate rock and in some cases it may be desirable to calcine the phosphate mineral material prior to acidualtion and mixing the cementitious components.
A process for the formation of magnesian cement having low water solubility and long term retention of mechanical properties. The process comprises acidulating insoluble basic, hydroxy and/or fluorophosphatic mineral material to activate it prior to or after mixing the mineral material with reactive magnesium oxide source material such as calcined dolomite or calcined magnesite, source material for magnesium chloride and/or sulphate such as bitterns, magnesium chloride hexahydrate or epsomite and sufficient water to make a workable slurry, with or without other common additives. The mineral material may be in the form of low grade phosphate rock and in some cases it may be desirable to calcine the phosphate mineral material prior to acidualtion and mixing the cementitious components.
Description
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~
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~
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~.
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 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 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 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 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 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 ~
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.
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 ~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~ $o~ ubill~ __ _ 50lubll~y ~ w~ight lo~, p~r~ent . ~ ~ ..
Amourlt of Acld Ser~e~: 1 ~ .~
( part~/100 p~ Mç~0 ) Phosp}L~ric:R~clc Pho~ph~te '~ k phosphate Ac~id Alone~ phos ~cld ~ sulphl-rlc 0 21.~ 2~.8 ~Z.0 Q.g 8.5 5.~ 10.6 l.8 5.2 3.D ~.6 2.8 5.~ 2.6 7.0 3.7 3.5 1.9 4.5 5.~ 2.7 l.~ 4.0 7.4 ~.~ 1.7 4.7 ~V~ E
SENT BY DAVIES ~ (:OLLISON ; .3~ 1; 17:17; .~iELE~O~ 'E~41~ 0~
~ ~/1 i~76 2 0 ~ ~ 414 PC~/hU~/01113~
~,~
~wo type~ of c~nen~ ware prep~red from tha hlgh S gr~de cal;;lne~ m~gne~lts from Kunwa~ara, Queensl~nd: a water reRl~nt cement oontaining ~aAd, r~ck phosphate an~ pho~phoric a ::id and a c:ontrol ~ement containll-y no additive ot~er than s~nd For t}~ pho~ph~te Inodi~ied c~ment, ~ dry mlx was prepar~d ~ronl 1170 Çl ~ flnely g~ound KunwE~rar~ calcine~
magn~sit~ alcln~d ~00 ~; free Mg0 9~ . 5 wt . ~ ) and 5 ky 4~ dry ~3harp guallty ~lldln~ ~and ln a mlxer of conunerc:l~l deYlgn. A ~remlx wa~ separat~ly pr~pared by, 15 addins~ 50 51 phosphoric acld ~o ~ ~lurry c: f 200 g Chrlstma~ land C s~rade phospha~e rock and lt~0 ml wat~r.
A~ter 15 mlnute~ 130 S~ of Runwarar~ c~lc~ ned Inagr~3site was add~ad to the pho!3ph~te premlx wlt}l ~lrring. l'his mlxtur~ ~orm~d ~ dry m~x ~nd wA~ ~ubsequantly slurrled ~0 l~7ith an<: ther 100 ml of water, and w~h~d into the ~gO-~and dry mix with 1~0~ ~nl of magne~ium chlor$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 ~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~
~ 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-
JO PO/I 1~76 2 ~ 1 4 ~/AO~J~13~
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~
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~.
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 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 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 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 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 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 ~
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.
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 ~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~ $o~ ubill~ __ _ 50lubll~y ~ w~ight lo~, p~r~ent . ~ ~ ..
Amourlt of Acld Ser~e~: 1 ~ .~
( part~/100 p~ Mç~0 ) Phosp}L~ric:R~clc Pho~ph~te '~ k phosphate Ac~id Alone~ phos ~cld ~ sulphl-rlc 0 21.~ 2~.8 ~Z.0 Q.g 8.5 5.~ 10.6 l.8 5.2 3.D ~.6 2.8 5.~ 2.6 7.0 3.7 3.5 1.9 4.5 5.~ 2.7 l.~ 4.0 7.4 ~.~ 1.7 4.7 ~V~ E
SENT BY DAVIES ~ (:OLLISON ; .3~ 1; 17:17; .~iELE~O~ 'E~41~ 0~
~ ~/1 i~76 2 0 ~ ~ 414 PC~/hU~/01113~
~,~
~wo type~ of c~nen~ ware prep~red from tha hlgh S gr~de cal;;lne~ m~gne~lts from Kunwa~ara, Queensl~nd: a water reRl~nt cement oontaining ~aAd, r~ck phosphate an~ pho~phoric a ::id and a c:ontrol ~ement containll-y no additive ot~er than s~nd For t}~ pho~ph~te Inodi~ied c~ment, ~ dry mlx was prepar~d ~ronl 1170 Çl ~ flnely g~ound KunwE~rar~ calcine~
magn~sit~ alcln~d ~00 ~; free Mg0 9~ . 5 wt . ~ ) and 5 ky 4~ dry ~3harp guallty ~lldln~ ~and ln a mlxer of conunerc:l~l deYlgn. A ~remlx wa~ separat~ly pr~pared by, 15 addins~ 50 51 phosphoric acld ~o ~ ~lurry c: f 200 g Chrlstma~ land C s~rade phospha~e rock and lt~0 ml wat~r.
A~ter 15 mlnute~ 130 S~ of Runwarar~ c~lc~ ned Inagr~3site was add~ad to the pho!3ph~te premlx wlt}l ~lrring. l'his mlxtur~ ~orm~d ~ dry m~x ~nd wA~ ~ubsequantly slurrled ~0 l~7ith an<: ther 100 ml of water, and w~h~d into the ~gO-~and dry mix with 1~0~ ~nl of magne~ium chlor$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 ~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~
~ 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-
Claims (12)
1. A process for forming a water resistant magnesian cementitious product which comprises admixing oxide phosphatic material with a reactive magnesium oxide source material, a magnesium salt source material, the salt being selected from one or both of chloride and sulphate, and sufficient water to provide a workable slurry and setting the slurry, and wherein the phosphatic material comprises an insoluble basic, hydroxy and/or fluoro phosphatic mineral material which is activated at least by partial acidulation.
2. A process according to claim 1 wherein acidulation is performed on the phosphatic mineral material using phosphoric acid, sulphuric acid or a combination of the two acids.
3. A process according to claim 1 wherein acidulation of the phosphatic mineral material is performed prior to mixing with the reactive magnesium oxide source material and the magnesium salt source material.
4. A process according to claim 3 wherein a substantially dry premix comprising the acidulated phosphatic mineral material with some or all of the reactive magnesium oxide source material is mixed with the magnesium salt source material and sufficient water to provide the workable slurry.
5. A process according to claim 1 wherein the phosphatic mineral material is calcined prior to acidulation and to mixing with the reactive magnesium oxide source material and the magnesium salt source material.
6. A process according to claim 1 wherein the SUBSTITUE SHEET
phosphatic mineral material comprises calcian hydroxyphosphates, calcian flurophosphates or mixtures of the two.
phosphatic mineral material comprises calcian hydroxyphosphates, calcian flurophosphates or mixtures of the two.
7. A process according to claim 6 wherein the phosphatic mineral material comprises calcium aluminium hydroxyphosphates.
8. A process according to claim 1 wherein the magnesium salt comprises magnesium chloride which is present as magnesium chloride hexahydrate.
9. A process according to claim 1 wherein the magnesium salt comprises magnesium chloride which is present as bitterns.
10. A process according to claim 9 wherein the bitterns has an Mg/Na ratio greater than 8.
11. A process according to claim 1 wherein the reactive magnesium oxide source material comprises a calcined magnesium carbonate mineral selected from one or both of magnesium and doiomite, calcined brucite, calcined magnesium hydroxide or mixtures of any two or more.
12. A water resistant magnesian cementitious product comprising a cured reaction product of a slurry of a reactive magnesium oxide source material and a magnesium salt source material with water, said salt being selected from one or both of chloride and sulphate in its lattice structure which is derived from at least partially acidulated basic, hydroxy and/or fluorophosphosphatic mineral material.
SUBSTITUTE SHEET
SUBSTITUTE SHEET
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AUPJ352289 | 1989-04-05 | ||
| AUPJ3522 | 1989-04-05 | ||
| AUPJ6616 | 1989-09-27 | ||
| AUPJ661689 | 1989-09-27 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2051414A1 true CA2051414A1 (en) | 1990-10-06 |
Family
ID=25643657
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2051414 Abandoned CA2051414A1 (en) | 1989-04-05 | 1990-04-05 | Process for forming water resistant magnesian cement introduction |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0469002A4 (en) |
| CA (1) | CA2051414A1 (en) |
| NZ (1) | NZ233232A (en) |
| WO (1) | WO1990011976A1 (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5645637A (en) * | 1994-05-30 | 1997-07-08 | Baran Advanced Materials 94 Ltd. | Foamed magnesite cement and articles made therewith |
| AU779788C (en) * | 2000-01-27 | 2008-01-03 | Tececo Pty Ltd | Reactive magnesium oxide cements |
| NZ520426A (en) | 2000-01-27 | 2004-09-24 | Tececo Pty Ltd | A hydraulic cement comprising a reactive magnesium oxide |
| US11117836B2 (en) | 2017-11-07 | 2021-09-14 | Mitek Holdings, Inc. | Ultra stable structural laminate |
| US10167230B1 (en) * | 2017-11-07 | 2019-01-01 | Jet Products, Llc | Ultra stable tile backer board formulation |
| WO2022032348A1 (en) * | 2020-08-12 | 2022-02-17 | UBIQ Technology Pty Ltd | High durability magnesium oxychloride cement |
| CN114525079B (en) * | 2022-01-19 | 2023-12-29 | 北京林业大学 | Aldehyde-free flame-retardant magnesium oxychloride cement-based wood adhesive and preparation method thereof |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2391493A (en) * | 1942-04-21 | 1945-12-25 | Titanium Alloy Mfg Co | Quick setting cement |
| US4352694A (en) * | 1980-07-18 | 1982-10-05 | Norcem A.S. | Process of producing sorel cement |
| CA1277342C (en) * | 1985-05-20 | 1990-12-04 | Fawzy G. Sherif | Fast-setting cements from ammonium phosphate fertilizer solution |
-
1990
- 1990-04-05 WO PCT/AU1990/000132 patent/WO1990011976A1/en not_active Application Discontinuation
- 1990-04-05 CA CA 2051414 patent/CA2051414A1/en not_active Abandoned
- 1990-04-05 EP EP19900906038 patent/EP0469002A4/en not_active Withdrawn
- 1990-04-05 NZ NZ23323290A patent/NZ233232A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| EP0469002A1 (en) | 1992-02-05 |
| NZ233232A (en) | 1992-09-25 |
| WO1990011976A1 (en) | 1990-10-18 |
| EP0469002A4 (en) | 1992-12-02 |
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