Ana kwatanta ƙananan simintin siminti na al'ada da na gargajiya na al'ada na al'ada. Adadin ƙarin siminti na al'ada aluminate simintin refractory castables yawanci shine 12-20%, kuma adadin ruwa gabaɗaya shine 9-13%. Saboda yawan adadin ruwa da aka ƙara, jikin simintin yana da pores da yawa, ba shi da yawa, kuma yana da ƙananan ƙarfi; saboda yawan adadin siminti da aka ƙara, ko da yake ana iya samun mafi girma na al'ada da ƙananan zafin jiki, ƙarfin yana raguwa saboda canjin crystalline na calcium aluminate a matsakaicin zafi. A bayyane yake, CaO da aka gabatar yana amsawa tare da SiO2 da Al2O3 a cikin simintin simintin don samar da wasu ƙananan abubuwa masu narkewa, wanda ke haifar da lalacewar kayan zafi mai zafi.
Lokacin da ultrafine foda fasahar, high-inganci admixtures da kimiyya barbashi gradation ana amfani da, da siminti abun ciki na castable an rage zuwa kasa da 8% da ruwa abun ciki an rage zuwa ≤7%, da kuma low-ciment jerin refractory castable iya zama. da aka shirya kuma aka kawo cikin Abubuwan da ke cikin CaO shine ≤2.5%, kuma alamun aikin sa gabaɗaya sun wuce na aluminate simintin siminti. Irin wannan nau'in simintin gyaran fuska yana da thixotropy mai kyau, wato, kayan da aka gauraye yana da wani nau'i kuma ya fara gudana tare da ɗan ƙarfin waje. Lokacin da aka cire ƙarfin waje, yana kula da siffar da aka samu. Saboda haka, ana kuma kiransa thixotropic refractory castable. Casable refractory mai gudana da kai kuma ana kiransa thixotropic refractory castable. Yana cikin wannan rukunin. Ba a fayyace ainihin ma'anar ƙananan simintin siminti ba ya zuwa yanzu. Ƙungiyar Gwaje-gwaje da Kayayyakin Amirka (ASTM) ta fayyace da rarraba simintin gyare-gyare bisa ga abubuwan da ke cikin su na CaO.
Maɗaukaki da ƙarfi mai ƙarfi sune fitattun fasalulluka na ƙananan simintin siminti mai jujjuyawa. Wannan yana da kyau don inganta rayuwar sabis da aikin samfurin, amma kuma yana kawo matsala ga yin burodi kafin amfani, wato, zubar da ruwa zai iya faruwa cikin sauƙi idan ba ku da hankali yayin yin burodi. Al'amarin fashewar jiki na iya buƙatar sake zubowa aƙalla, ko kuma yana iya yin haɗari ga lafiyar ma'aikatan da ke kewaye da su a lokuta masu tsanani. Don haka, kasashe daban-daban sun kuma gudanar da bincike daban-daban kan toya simintin siminti maras nauyi. Babban matakan fasaha sune: ta hanyar tsara madaidaicin murhun tanda da kuma gabatar da ingantattun abubuwan hana fashewa, da dai sauransu, wannan na iya sa katun da aka cire ruwa yana kawar da su lafiyayye ba tare da haifar da wasu lahani ba.
Ultrafine foda fasaha ne key fasaha ga low-cimenti jerin refractory castables (a halin yanzu mafi yawan ultrafine powders amfani da tukwane da kuma refractory kayan ne ainihin tsakanin 0.1 da 10m, kuma sun yafi aiki a matsayin watsawa accelerators da structural densifiers. .The tsohon sa da tukwane. siminti barbashi sosai tarwatsa ba tare da flocculation, yayin da na karshen ya sa micropores a cikin zub da jiki cika da kuma inganta ƙarfi.
A halin yanzu da aka saba amfani da nau'in ultrafine powders sun haɗa da SiO2, α-Al2O3, Cr2O3, da dai sauransu. Ƙayyadaddun yanki na SiO2 micropowder yana da kusan 20m2 / g, kuma girmansa yana da kusan 1/100 na girman siminti, don haka yana da kyau. kayan cikawa. Bugu da ƙari, SiO2, Al2O3, Cr2O3 micropowder, da dai sauransu na iya samar da kwayoyin colloidal a cikin ruwa. Lokacin da mai watsawa ya kasance, an samar da wani rufin lantarki mai ruɓani biyu a saman ɓangarorin don haifar da tsangwama na electrostatic, wanda ya shawo kan ƙarfin van der Waals tsakanin barbashi kuma yana rage ƙarfin haɗin gwiwa. Yana hana adsorption da flocculation tsakanin barbashi; a lokaci guda kuma, ana adsorbed da dispersant a kusa da barbashi don samar da wani ƙarfi Layer, wanda kuma yana ƙara yawan ruwa na castable. Wannan kuma yana daya daga cikin hanyoyin ultrafine foda, wato, ƙara ultrafine foda da masu rarraba masu dacewa na iya rage yawan ruwa na simintin gyaran fuska da kuma inganta ruwa.
Saitin da taurin ƙananan simintin simintin gyare-gyare shine sakamakon haɗakar aikin haɗin hydration da haɗin haɗin kai. A hydration da hardening na calcium aluminate ciminti ne yafi hydration na na'ura mai aiki da karfin ruwa matakai CA da CA2 da kuma crystal girma tsarin na su hydrates, wato, sun amsa da ruwa don samar da hexagonal flake ko allura-dimbin CAH10, C2AH8 da Hydration kayayyakin irin wannan. kamar yadda cubic C3AH6 lu'ulu'u da Al2O3аq gels sa'an nan samar da interconnected condensation-crystallization tsarin cibiyar sadarwa a lokacin curing da dumama tafiyar matakai. The agglomeration da bonding ne saboda aiki SiO2 ultrafine foda forming colloidal barbashi lokacin da ya hadu da ruwa, kuma ya sadu da ions sannu a hankali rabu da kara ƙari (watau electrolyte abu). Saboda cajin saman biyun ya sabawa, wato, saman colloid ya tallata ions masu ƙima, yana haifar da £ 2 yuwuwar raguwa da haɓakawa yana faruwa lokacin da adsorption ya kai ga “matsayin isoelectric”. A wasu kalmomi, lokacin da ƙwanƙwasa electrostatic a saman ɓangarorin colloidal bai kai abin jan hankali ba, haɗin haɗin gwiwa yana faruwa tare da taimakon van der Waals ƙarfi. Bayan da aka haɗa simintin da aka haɗa da silica foda ya ƙare, ƙungiyoyin Si-OH da aka kafa a saman SiO2 sun bushe kuma an bushe su zuwa gada, suna samar da tsarin cibiyar sadarwa na siloxane (Si-O-Si), don haka taurin kai. A cikin tsarin cibiyar sadarwa na siloxane, haɗin kai tsakanin silicon da oxygen ba sa raguwa yayin da yawan zafin jiki ya karu, don haka ƙarfin kuma yana ci gaba da karuwa. A lokaci guda, a yanayin zafi mai zafi, tsarin hanyar sadarwa na SiO2 zai amsa tare da Al2O3 da aka nannade a ciki don samar da mullite, wanda zai iya inganta ƙarfin a matsakaici da yanayin zafi.
Lokacin aikawa: Fabrairu-28-2024
