Kaolin wani ma'adinai ne da ba na ƙarfe ba, wanda dutse ne mai yumɓu da yumɓu wanda galibi ya ƙunshi ma'adanai na yumɓu na ƙungiyar kaolinite. Saboda launinsa mai laushi da fari, ana kuma kiransa da ƙasar Baiyun. An sanya masa suna ne bayan ƙauyen Gaoling da ke Jingdezhen, Lardin Jiangxi.

Tsarkakken kaolin ɗinsa fari ne, mai laushi, kuma mai laushi, yana da kyawawan halaye na zahiri da sinadarai kamar su ƙarfin lantarki da juriya ga wuta. Abubuwan da ke cikin ma'adinansa galibi sun ƙunshi ma'adanai kamar kaolinite, halloysite, hydromica, illite, montmorillonite, da kuma quartz da feldspar. Ana amfani da Kaolin sosai wajen yin takarda, yumbu, da kayan da ba sa jure wa iska, sai kuma shafa fenti, cika roba, glazes na enamel, da kayan siminti na farin. Ana amfani da ƙaramin adadin a cikin filastik, fenti, launuka, ƙafafun niƙa, fensir, kayan kwalliya na yau da kullun, sabulu, magungunan kashe ƙwari, magunguna, yadi, man fetur, sinadarai, kayan gini, tsaron ƙasa, da sauran sassan masana'antu.

Ma'adanai da ke cikin kaolin a yanayi galibi an raba su zuwa ma'adanai na yumbu da ma'adanai marasa yumbu. Ma'adanai na yumbu galibi sun haɗa da ma'adanai na ƙungiyar kaolinite da ƙaramin adadin montmorillonite, mica, da chlorite; Ma'adanai marasa yumbu galibi sun haɗa da feldspar, quartz, da hydrates, da kuma wasu ma'adanai na ƙarfe kamar hematite, siderite, limonite, titanium minerals kamar rutile, da kuma ma'adanai na halitta kamar zare na shuka. Babban abin da ke ƙayyade aikin kaolin shine ma'adanai na yumbu.

Kaolin ya zama muhimmin kayan ma'adinai ga masana'antu da dama kamar yin takarda, yumbu, roba, injiniyan sinadarai, shafa, magunguna, da kuma tsaron ƙasa.

Masana'antar yumbu ita ce masana'antar farko kuma mafi amfani da ita don amfani da kaolin. Matsakaicin yawan amfani shine kashi 20% zuwa 30% na dabarar. Matsayin kaolin a cikin yumbu shine gabatar da Al2O3, wanda ke da amfani ga samuwar mullite, yana inganta daidaiton sinadarai da ƙarfin sintering. A lokacin sintering, kaolin yana ruɓewa don samar da mullite, yana samar da babban tsarin ƙarfin jiki. Wannan zai iya hana lalacewar samfurin, faɗaɗa zafin wuta, da kuma ba jiki wani matakin fari. A lokaci guda, kaolin yana da wani matakin plasticity, mannewa, dakatarwa, da ikon haɗawa, yana ba da laka da glaze mai kyau, yana sa jikin laka na yumbu ya zama mai amfani ga jikin abin hawa da grouting, yana sa ya zama mai sauƙin samarwa. Idan aka yi amfani da shi a cikin wayoyi, yana iya ƙara rufi da rage asarar dielectric.

Ba wai kawai yumbu yana da ƙa'idodi masu tsauri don plasticity, mannewa, raguwar bushewa, ƙarfin bushewa, raguwar sintering, halayen sintering, juriyar wuta, da farin kaolin bayan harbi ba, har ma yana da kaddarorin sinadarai, musamman kasancewar abubuwan chromogenic kamar ƙarfe, titanium, jan ƙarfe, chromium, da manganese, waɗanda ke rage farin bayan harbi kuma suna haifar da tabo.

Bukatar girman barbashi na kaolin gabaɗaya ita ce mafi ƙanƙanta ya fi kyau, don haka laka mai laushi yana da kyakkyawan filastik da ƙarfin bushewa. Duk da haka, don hanyoyin yin siminti waɗanda ke buƙatar saurin siminti, saurin grouting mai sauri, da saurin bushewa, ya zama dole a ƙara girman barbashi na sinadaran. Bugu da ƙari, bambancin da ke cikin crystallinity na kaolin a cikin kaolin zai kuma yi tasiri sosai kan aikin aikin billets na porcelain. Idan crystallinity yana da kyau, ƙarfin plasticity da haɗin kai sun yi ƙasa, raguwar bushewa ƙarami ne, zafin sintering yana da yawa, kuma yawan ƙazanta shi ma ya ragu; Akasin haka, ƙarfinsa ya fi girma, raguwar bushewa ya fi girma, zafin sintering yana da ƙasa, kuma yawan ƙazanta da ya dace shi ma ya fi girma.