Ngokwezibalo ezingaphelele, ukukhiqizwa kwamanje komhlaba wonke kwe-non-ionic cellulose ether sekufinyelele amathani angaphezu kuka-500,000, kanti i-hydroxypropyl methyl cellulose ibalwe ku-80% kuya kumathani angaphezu kuka-400,000, eChina eminyakeni emibili yakamuva izinkampani eziningi ziye zandisa ukukhiqizwa ngokushesha. ukwandisa umthamo usufinyelele amathani angaba ngu-180 000, amathani angaba ngu-60 000 okusetshenziswa ekhaya, Kulokhu, amathani angaphezu kwezigidi ezingu-550 asetshenziswa embonini futhi cishe amaphesenti angu-70 asetshenziswa njengezithasiselo zokwakha.
Ngenxa yokusetshenziswa okuhlukene kwemikhiqizo, izidingo zenkomba yomlotha wemikhiqizo nazo zingahluka, ukuze ukukhiqizwa kuhlelwe ngokuvumelana nezidingo zamamodeli ahlukene enqubweni yokukhiqiza, ehambisana nomphumela wokonga amandla, ukunciphisa ukusetshenziswa kanye nokunciphisa ukukhishwa.
1 i-hydroxypropyl methyl cellulose ash kanye namafomu ayo akhona
I-Hydroxypropyl methylcellulose (HPMC) ibizwa ngokuthi umlotha ngokwamazinga ekhwalithi yemboni kanye ne-sulphate noma izinsalela ezishisayo yi-pharmacopoeia, engaqondwa kalula njengokungcola kukasawoti wezinto eziphilayo emkhiqizweni. Inqubo yokukhiqiza eyinhloko yi-alkali eqinile (i-sodium hydroxide) ngokusabela ekulungisweni kokugcina kwe-pH kusawoti ongathathi hlangothi kanye nezinto zokusetshenziswa ezitholakala esambeni sikasawoti ongaphili.
Indlela yokunquma umlotha ophelele; Ngemuva kokuthi inani elithile lamasampula likhishwa nge-carbonized futhi lishiswe esithandweni sokushisa okuphezulu, izinto eziphilayo zikhishwa nge-oxidized futhi zibole, ziphunyuke ngesimo se-carbon dioxide, i-nitrogen oxides namanzi, kuyilapho izinto ezingaphili zihlala zisesimweni se-sulfate, i-phosphate, i-carbonate, i-chloride namanye ama-salts we-inorganic kanye nama-oxide ensimbi. Lezi zinsalela ziwumlotha. Inani lomlotha ophelele kusampula lingabalwa ngokukala okusele.
Ngokwenqubo esebenzisa ama-acids ahlukene futhi izokhiqiza usawoti ohlukile: ikakhulukazi i-sodium chloride (ekhiqizwa ukusabela kwe-ion chloride ku-chloromethane ne-sodium hydroxide) kanye nezinye i-acids neutralization ingakhiqiza i-acetate ye-sodium, i-sodium sulfide noma i-sodium oxalate.
2. Izidingo zomlotha we-industrial grade hydroxypropyl methyl cellulose
IHydroxypropyl methyl cellulose isetshenziswa kakhulu njengokuqina, i-emulsification, ukwakhiwa kwefilimu, i-colloid evikelayo, ukugcinwa kwamanzi, ukunamathela, i-anti-enzyme kanye ne-inert ye-metabolic nokunye ukusetshenziswa, isetshenziswa kabanzi emikhakheni eminingi yezimboni, engahlukaniswa ngokulandelayo: izici:
(1) Ukwakhiwa: indima eyinhloko ukugcinwa kwamanzi, ukuqina, i-viscosity, i-lubrication, usizo lokugeleza lokuthuthukisa usimende kanye ne-gypsum machinability, ukupompa. Izembatho zezakhiwo, izimbotshana ze-latex zisetshenziswa ngokuyinhloko njenge-colloid evikelayo, ukwakheka kwefilimu, i-agent yokuqina kanye nosizo lokumiswa kwe-pigment.
(2) I-Polyvinyl chloride: isetshenziswa ikakhulukazi njenge-disperant ekuphenduleni kwe-polymerization yohlelo lokumiswa kwe-polymerization.
(3) amakhemikhali nsuku zonke: ngokuyinhloko asetshenziswa njengezinto zokuzivikela, angathuthukisa umkhiqizo we-emulsification, i-anti-enzyme, ukuhlakazwa, ukunamathela, umsebenzi ongaphezulu, ukwakheka kwefilimu, ukuthambisa, ukugwedla, ukwakha, i-ejenti yokukhulula, i-softener, i-lubricant nezinye izakhiwo;
(4) Imboni yezemithi: embonini yezemithi isetshenziswa kakhulu ekukhiqizweni kokulungiselela, isetshenziswa njengokulungiswa okuqinile kwe-ejenti yokunamathela, impahla ye-capsule engenalutho, i-binder, esetshenziselwa ukukhululwa kancane kwamathambo emithi, ukwakhiwa kwefilimu, i-pore-forming agent, esetshenziswa njengoketshezi, ukuqina kokulungiswa okuqinile, ukufakwa kwe-emulsification, ukumiswa, ukusetshenziswa kwe-matrix;
(5) I-Ceramics: isetshenziswa njenge-ejenti yokwakha isibopho se-ceramic industry billet, i-ejenti ehlakazayo yombala ocwebezelayo;
(6) ukwenza iphepha: ukuhlakazwa, ukufaka imibala, ukuqinisa;
(7) Ukuphrinta kwendwangu kanye nokudaya: i-pulp yendwangu, umbala, isandiso sombala:
(8) Ukukhiqizwa kwezolimo: kwezolimo, ingasetshenziswa ukwelapha imbewu yezitshalo, ukuthuthukisa izinga lokuhluma, ukuvikela umswakama nokuvimbela isikhutha, ukugcina izithelo zintsha, i-ejenti yokukhululwa kancane kamanyolo wamakhemikhali nezibulala-zinambuzane, njll.
Ngokwempendulo yesipiliyoni esingenhla sesicelo sesikhathi eside nesifinyezo samazinga okulawula angaphakathi kwamanye amabhizinisi angaphandle nasekhaya, imikhiqizo ethile kuphela ye-polyvinyl chloride polymerization kanye namakhemikhali ansuku zonke adingekayo ukuze kulawulwe usawoti ongaphansi kuka-0.010, kanye ne-pharmacopoeia. yamazwe ahlukahlukene idinga ukulawula usawoti ngaphansi kuka-0.015. Futhi okunye ukusetshenziswa kokulawulwa kukasawoti kungaba banzi, ikakhulukazi imikhiqizo yokwakha ngaphezu kokukhiqizwa kwe-putty, usawoti wepende unezidingo ezithile, okusele kungalawula usawoti <0.05 ongahlangabezana nokusetshenziswa ngokuyisisekelo.
3 inqubo ye-hydroxypropyl methyl cellulose kanye nendlela yokususa usawoti
Izindlela eziyinhloko zokukhiqiza i-hydroxypropyl methyl cellulose ekhaya naphesheya zimi kanje:
(1) Indlela yesigaba soketshezi (indlela yodaka) : impushana ecolekile ye-cellulose ezochotshozwa ihlakazwa cishe izikhathi ezi-10 ku-solvent ye-organic ku-reactor eqondile noma evundlile enokuyaluza okuqinile, bese kwengezwa i-lye yobuningi kanye ne-etherifying agent ukuze kuphenduleke. Ngemuva kokusabela, umkhiqizo wagezwa, womiswa, uchotshoziwe futhi wahlungwa ngamanzi ashisayo.
(2) Indlela yesigaba segesi (indlela ye-gas-solid) : Ukusabela kwempushana ye-cellulose esezochotshozwa kuqedwa esimweni esomile ngokungeza ngokuqondile i-lye yobuningi kanye ne-etherifying agent kanye nenani elincane lemikhiqizo ephuma endaweni yokubilisa ephansi. kureactor evundlile enokuyaluza okuqinile. Awekho ama-solvents engeziwe adingekayo ekuphenduleni. Ngemuva kokusabela, umkhiqizo wagezwa, womiswa, uchotshoziwe futhi wahlungwa ngamanzi ashisayo.
(3) Indlela ye-Homogeneous (indlela yokuhlakazeka) : Evundlile ingangezwa ngokuqondile ngemva kokuchotshozwa kwe-cellulose nge-reactor enamandla eshukumisayo ehlakazeke ku-naoh/urea (noma ezinye izincibilikisi ze-cellulose) cishe izikhathi ezingu-5 ~ 8 ze-solvent yamanzi efriza ku-solvent, bese ukwengeza i-lye eningi kanye ne-etherifying agent ekuphenduleni, ngemva kokusabela nge-acetone precipitation reaction good cellulose ether, Ibe-ke igezwa ngamanzi ashisayo, yomiswe, ichotshoziwe futhi ihlungwe ukuze uthole umkhiqizo ophelile. (Ayikakabikho emkhiqizweni wezimboni).
Ukuphela kokusabela kungakhathaliseki ukuthi yiziphi izinhlobo zezindlela ezishiwo ngenhla ezinosawoti omningi, ngokusho kwenqubo ehlukene engakhiqiza yilezi: i-sodium chloride ne-sodium acetate, i-sodium sulfide, i-sodium oxalate, nokunye ukuxuba usawoti, okudingekayo ngokusebenzisa i-desalination, ukusetshenziswa kukasawoti ekuncibilikeni kwamanzi, ngokuvamile ngokuwashwa okuningi kwamanzi ashisayo, manje imishini eyinhloko nendlela yokugeza yilezi:
(1) isihlungi se-vacuum sebhande; Lokhu ikwenza ngokujikijela impahla eluhlaza eqediwe ngamanzi ashisayo bese igeza usawoti ngokusabalalisa udaka ngokulinganayo phezu kwebhande lokuhlunga ngokufafaza amanzi ashisayo phezu kwalo bese liyivacupha ngezansi.
(2) I-centrifuge evundlile: ekupheleni kokusabela kwento engahluziwe ingene odaka ngamanzi ashisayo ukuze ihlambulule usawoti oncibilike emanzini ashisayo bese kuthi ngokuhlukana kwe-centrifugation ibe ukwehlukana okuqinile uketshezi ukuze kukhishwe usawoti.
(3) ngesihlungi se-pressure, ekupheleni kokusabela kwento engahluziwe ingene odaka ngamanzi ashisayo, ingene kusihlungi somfutho, kuqala ngamanzi aphephethwa ngesitimu bese kuthi ngamanzi ashisayo fafaza izikhathi ezingu-N ngamanzi apheshulwe ngesitimu ukuze hlukanisa futhi ususe usawoti.
Ukugeza ngamanzi ashisayo ukususa usawoti oncibilikisiwe, ngoba isidingo sokujoyina amanzi ashisayo, ukugeza, kulapho kulapho aphansi khona okuqukethwe komlotha, futhi okuphambene nalokho, ngakho umlotha wawo uhlobene ngokuqondile nokuthi ingakanani inani lamanzi ashisayo, imboni jikelele. umkhiqizo uma ukulawula umlotha ngaphansi kuka-1% USEBENZISA amanzi ashisayo amathani ayi-10, uma ukulawula ngaphansi kuka-5% kuzodinga amathani angu-6 ashisayo.
Amanzi angcolile e-Cellulose ether anesidingo se-oksijini yamakhemikhali (COD) engaphezu kuka-60 000 mg/L kanye nosawoti ongaphezu kuka-30 000 mg/L, ngakho kubiza kakhulu ukwelapha amanzi anjalo angcolile, ngoba kunzima ukuwaqondisa ngokuqondile. Amakhemikhali kasawoti aphezulu kangaka, futhi akuvunyelwe ukuncibilika ngokuvumelana nezidingo zamanje zokuvikelwa kwemvelo kazwelonke. Isixazululo esiyinhloko ukukhipha usawoti nge-distillation. Ngakho-ke, ithani elilodwa elingaphezulu lokugeza amanzi abilayo lizokhipha ithani elilodwa indle eyengeziwe. Ngokobuchwepheshe bamanje be-MUR obunamandla amakhulu, izindleko eziphelele zethani ngalinye lokugeza amanzi agxilile zingamayuan angama-80, futhi izindleko eziyinhloko ukusetshenziswa kwamandla okuphelele.
Umthelela womlotha o-4 kuzinga lokugcinwa kwamanzi le-industrial hydroxypropyl methyl cellulose
I-HPMC idlala ikakhulukazi izindima ezintathu ekugcineni amanzi, ukuqina kanye nokwenza lula ukwakhiwa kwezinto zokwakha.
Ukugcinwa kwamanzi: ukwandisa isikhathi sokuvulwa kokugcinwa kwamanzi okubonakalayo, ukusiza ukusebenza kwawo kwe-hydration ngokugcwele.
Ukuqina: I-Cellulose ingaqiniswa ukuze idlale ukumiswa, ukuze isisombululo sokugcina iyunifomu phezulu naphansi indima efanayo, ukumelana nokulenga ukugeleza.
Ukwakhiwa: I-Cellulose Lubrication, ingaba nokwakhiwa okuhle. I-HPMC ayibambi iqhaza ekutheni ukusabela kwamakhemikhali, kudlala indima yokusiza kuphela. Enye yezinto ezibaluleke kakhulu ukugcinwa kwamanzi, ukugcinwa kwamanzi odaka kuthinta i-homogenization yodaka, bese kuthinta izakhiwo zemishini nokuqina kodaka oluqinile. Udaka lwe-masonry nodaka lwe-plaster yizingxenye ezimbili ezibalulekile zezinto zodaka, futhi insimu ebalulekile yokusetshenziswa kodaka lwamatshe kanye nodaka lwe-plaster yisakhiwo samatshe. Njengoba i-block ekusetshenzisweni kwenqubo yemikhiqizo isesimweni esomile, ukuze kuncishiswe ibhulokhi elomile lokumuncwa kwamanzi anamandla odaka, ukwakhiwa kuthatha ibhulokhi ngaphambi kokumanzisa, ukuvimba okuqukethwe okuthile komswakama, gcina umswakama odongeni. ukuvimba ukumuncwa ngokweqile kwempahla, kungagcina i-hydration evamile yangaphakathi ye-gelling material njengosimende nosimende. Kodwa-ke, izici ezinjengomehluko wohlobo lwebhulokhi kanye nedigri yokumanzisa ngaphambili kwesayithi kuzothinta izinga lokulahlekelwa kwamanzi nokulahlekelwa kwamanzi odaka, okuzoletha izingozi ezifihliwe kukhwalithi iyonke yesakhiwo somashi. Udaka olunokugcinwa kwamanzi okuhle kakhulu lungaqeda ithonya lezinto zokuvimba kanye nezici zomuntu, futhi uqinisekise ukufana kodaka.
Umthelela wokugcinwa kwamanzi ekusebenzeni kokuqina kodaka ubonakala ikakhulukazi emthelela endaweni yesixhumi esibonakalayo phakathi kodaka nebhulokhi. Ngokulahleka kwamanzi okusheshayo kodaka ngokugcinwa kwamanzi okungekuhle, okuqukethwe kwamanzi odaka engxenyeni yesixhumi esibonakalayo akwanele, futhi usimende awukwazi ukufakwa emanzini ngokugcwele, okuthinta ukuthuthukiswa okujwayelekile kwamandla. Amandla ebhondi ezinto ezisekelwe kusimende akhiqizwa ikakhulukazi ukubambelela kwemikhiqizo ye-cement hydration. I-hydration enganele kasimende endaweni yesixhumi esibonakalayo kunciphisa amandla ebhondi yesixhumi esibonakalayo, kanye nokuqhuma okungenalutho kanye nokuqhekeka kodaka kuyanda.
Ngakho-ke, ukukhetha ebucayi kakhulu imfuneko yokugcinwa kwamanzi isakhiwo K brand amaqoqo amathathu viscosity ezahlukene, ngokusebenzisa izindlela ezahlukene ukugeza avele inombolo yenqwaba efanayo okulindelwe umlotha okulindelekile, bese ngokusho indlela yamanje evamile yokuhlola ukugcinwa kwamanzi (iphepha lokuhlunga indlela ) enombolweni efanayo yenqwaba yokuqukethwe komlotha okuhlukile kokugcinwa kwamanzi kwamaqembu amathathu amasampuli okucaciswe kanje:
4.1 Indlela yokuhlola yokuthola izinga lokugcinwa kwamanzi (indlela yephepha lokuhlunga)
4.1.1 Ukusetshenziswa kwezinsimbi nezinto zokusebenza
Ingxube kasimende enodaka, isilinda sokulinganisa, ibhalansi, isitophuwashi, isitsha sensimbi engagqwali, isipuni, indandatho yensimbi engagqwali (ububanzi bangaphakathi φ100 mm× ububanzi bangaphandle φ110 mm× ukuphakama 25 mm, iphepha lokuhlunga elisheshayo, isihlungi esinensayo, ipuleti lengilazi.
4.1.2 Izimpahla kanye nama-reagents
Ojayelekileko Osimende wasePortland (425#), ISANDABA ESIYINGA (ISISANDABA ESINGAKHO UDAKA ESIGEZWA AMANZI), ISAMBULO LOMKHIQIZO (HPMC), AMANZI ACANCE OKUHLOLA (AMANZI OKUTHOBELA, AMANZI AMAMADINI).
4.1.3 Izimo zokuhlaziya zokuhlola
Izinga lokushisa elabhorethri: 23±2 ℃; Umswakama ohlobene: ≥ 50%; Izinga lokushisa lamanzi elabhorethri liyafana negumbi lokushisa elingu-23 ℃.
4.1.4 Izindlela zokuhlola
Faka ipuleti lengilazi endaweni yokusebenza, faka isihlungi esinesisindo esingapheli (isisindo: M1) kuso, bese ufaka ucezu lwephepha lokuhlunga ngokushesha ephepheni lokuhlunga, bese ufaka isikhunta esiyindandatho yensimbi ephepheni lokuhlunga elisheshayo ( isikhunta esiyindandatho akufanele seqe isiyingi sephepha lokuhlunga okusheshayo).
Isisindo esinembile (425#) usimende 90 g; Isihlabathi esijwayelekile 210 g; Umkhiqizo (isampula) 0.125g; Thela esitsheni sensimbi engagqwali bese uxuba kahle (ingxube eyomile).
Sebenzisa isixube sikasimende (ibhodwe lokuxuba namaqabunga ahlanzekile futhi omile, ahlanzeke kahle futhi omile ngemva kokuhlolwa ngakunye, beka eceleni). Sebenzisa isilinda sokulinganisa ukukala u-72 ml wamanzi ahlanzekile (23 ℃), qala uthele ebhodweni elinyakazayo, bese uthela izinto ezilungisiwe, ungene ngemizuzu engama-30; Ngesikhathi esifanayo, phakamisa ibhodwe endaweni yokuxuba, qala i-mixer, futhi uqhube ngesivinini esiphansi (okungukuthi, ukugoqa kancane) ku-60 s; Yima imizuzwana engu-15 bese ukhuhla i-slurry odongeni kanye ne-blade ebhodweni; Qhubeka u-whisk ngokushesha ukuze ume imizuzwana engu-120. Thela (umthwalo) lonke udaka oluxubile esibunjeni sensimbi engagqwali ngokushesha, kanye nesikhathi kusukela ngesikhathi lapho udaka luthinta iphepha lokuhlunga elisheshayo (cindezela isitophuwashi). Ngemva kwemizuzu engu-2, isikhunta sendandatho saguqulwa futhi iphepha lokuhlunga elingapheli lakhishwa futhi likalwa (isisindo: M2). Yenza isilingo esingenalutho ngokwendlela engenhla (isisindo sephepha lesihlungi esingamahlalakhona ngaphambi nangemva kokukala yi-M3, M4)
Indlela yokubala imi kanje:
(1)
Lapho, i-M1 - isisindo sephepha lesihlungi esingamahlalakhona ngaphambi kokuhlolwa kwesampula; I-M2 - isisindo sephepha lokuhlunga elingapheli ngemva kokuhlolwa kwesampula; I-M3 - isisindo sephepha lokuhlunga elingapheli ngaphambi kokuhlolwa okungenalutho; I-M4 — isisindo sephepha lesihlungi esingamahlalakhona ngemva kokuhlolwa okungenalutho.
4.1.5 Izinyathelo zokuqapha
(1) izinga lokushisa lamanzi ahlanzekile kufanele libe ngu-23 ℃, futhi ukukala kufanele kube okunembile;
(2) ngemva kokuyixuba, susa ibhodwe elinyakazayo futhi ugovuze ngokulinganayo ngesipuni;
(3) isikhunta kufanele sifakwe ngokushesha, futhi udaka luzonyathelwa phansi futhi luqine ngenkathi lufaka;
(4) Qiniseka ukuthi ubeka isikhathi isikhathi lapho udaka luthinta iphepha lokuhlunga ngokushesha, futhi ungawutheli udaka ephepheni lokuhlunga langaphandle.
4.2 isampula
Izinombolo zebheshi ezintathu ezinama-viscosities ahlukene ohlobo olufanayo lwe-K zikhethiwe njenge: 201302028 viscosity 75 000 mPa·s, 20130233 viscosity 150 000 mPa·s, 20130236 viscosity 200 000 000 inombolo yokugeza eyahlukene thola inombolo yokugeza ehlukene kuya kokubili okufanayo umlotha (bheka Ithebula 3.1). Lawula ngokuqinile umswakama kanye ne-pH yeqoqo elifanayo lamasampuli ngangokunokwenzeka, bese wenza ukuhlolwa kwezinga lokugcinwa kwamanzi ngokwendlela engenhla (indlela yephepha lokuhlunga).
4.3 Imiphumela Yokuhlola
Imiphumela yokuhlaziywa kwenkomba yamaqoqo amathathu amasampula ikhonjisiwe kuThebula 1, imiphumela yokuhlolwa yamazinga okugcinwa kwamanzi ama-viscosities ahlukene iboniswa kuMfanekiso 1, futhi imiphumela yokuhlolwa yamazinga okugcinwa kwamanzi omlotha ne-pH ehlukene iboniswa kuMfanekiso 2. .
(1) Imiphumela yokuhlaziywa kwenkomba yamaqoqo amathathu amasampula ikhonjisiwe kuThebula loku-1
Ithebula 1 Imiphumela yokuhlaziya yamaqoqo amathathu amasampula
iphrojekthi
Inombolo yeqoqwana.
Umlotha %
pH
I-Viscosity/mPa, s
Amanzi / %
Ukugcinwa kwamanzi
201302028
4.9
4.2
75, 000,
6
76
0.9
4.3
74, 500,
5.9
76
20130233
4.7
4.0
150, 000,
5.5
79
0.8
4.1
140, 000,
5.4
78
20130236
4.8
4.1
200, 000,
5.1
82
0.9
4.0
195, 000,
5.2
81
(2) Imiphumela yokuhlolwa kokugcinwa kwamanzi yamaqoqo amathathu amasampula anama-viscosity ahlukene iboniswa kuMfanekiso 1.
I-FIG. 1 Imiphumela yokuhlolwa yokugcinwa kwamanzi kwamaqoqo amathathu amasampula anama-viscosity ahlukene
(3) Imiphumela yokutholwa kwezinga lokugcinwa kwamanzi yamaqoqo amathathu amasampula anokuqukethwe komlotha okuhlukile kanye ne-pH iboniswa kuMfanekiso 2.
I-FIG. 2 Imiphumela yokutholwa yezinga lokugcinwa kwamanzi lamaqoqo amathathu amasampula anokuqukethwe komlotha okuhlukile kanye ne-pH
Ngemiphumela yokuhlola engenhla, umthelela wezinga lokugcinwa kwamanzi ikakhulukazi livela ku-viscosity, i-viscosity ephezulu ngokuhlobene nezinga layo eliphezulu lokugcinwa kwamanzi liyoba libi ngokuphambene nalokho. Ukushintshashintsha kokuqukethwe komlotha ebangeni lika-1%~5% cishe akuthinti izinga layo lokugcinwa kwamanzi, ngakho-ke ngeke kuphazamise ukusebenza kwalo kokugcinwa kwamanzi.
5 isiphetho
Ukuze kwenziwe izinga lisebenze kakhudlwana kokungokoqobo futhi lihambisane nenkambiso ekhulayo yokonga amandla nokuvikelwa kwemvelo, kuphakanyiswa ukuthi:
Izinga lezimboni ze-industrial hydroxypropyl methyl cellulose lakhiwe ekulawuleni umlotha ngamamaki, afana nalawa: izinga 1 lokulawula umlotha <0.010, izinga 2 lokulawula umlotha <0.050. Ngale ndlela, umkhiqizi angakhetha ukuvumela umsebenzisi ukuthi abe nokukhetha okwengeziwe. Ngesikhathi esifanayo, intengo ingasethwa ngokusekelwe kumgomo wekhwalithi ephezulu kanye nenani eliphezulu ukuvimbela ukudideka kwemakethe. Okubaluleke kakhulu ukuthi ukongiwa kwamandla nokuvikelwa kwemvelo kwenza ukukhiqizwa kwemikhiqizo kube nobungane futhi kuhambisane nemvelo.
Isikhathi sokuthumela: Sep-09-2022