輕質硅(gui)磚又(you)稱硅(gui)質隔熱磚。二氧(yang)化硅(gui)在(zai)(zai)91%以上，體(ti)(ti)積密度(du)(du)在(zai)(zai)1.2g/cm3以下(xia)的(de)(de)(de)輕質耐(nai)(nai)火材料。耐(nai)(nai)火度(du)(du)和荷重軟化溫度(du)(du)與成(cheng)分相同的(de)(de)(de)普通(tong)硅(gui)磚相差(cha)不(bu)大。但由(you)于(yu)氣孔很(hen)多，故耐(nai)(nai)壓(ya)強度(du)(du)、抗(kang)渣性(xing)、抗(kang)腐蝕(shi)性(xing)等不(bu)如普通(tong)硅(gui)磚，而抗(kang)熱震性(xing)能(neng)卻有所提高。 采用(yong)(yong)細(xi)碎的(de)(de)(de)硅(gui)石做原料，其臨界粒度(du)(du)通(tong)常不(bu)超過1mm，而其中小于(yu)0.5mm的(de)(de)(de)顆粒不(bu)少于(yu)90%。在(zai)(zai)配料中加(jia)入易燃物(wu)質或(huo)采用(yong)(yong)氣體(ti)(ti)發生法(fa)形(xing)成(cheng)多孔結(jie)構，經(jing)燒成(cheng)而制得。也(ye)可制成(cheng)不(bu)燒制品。主要(yao)用(yong)(yong)于(yu)要(yao)求隔熱或(huo)減輕自重而不(bu)與熔融物(wu)直接(jie)接(jie)觸(chu)、不(bu)受侵蝕(shi)性(xing)氣體(ti)(ti)作用(yong)(yong)、不(bu)遭受溫度(du)(du)急變的(de)(de)(de)窯爐(lu)各(ge)個(ge)部位。在(zai)(zai)高溫下(xia)使用(yong)(yong)，不(bu)能(neng)與堿(jian)性(xing)耐(nai)(nai)火材料接(jie)觸(chu)。按材質不(bu)同，其使用(yong)(yong)溫度(du)(du)在(zai)(zai)1200～1550℃。 輕質硅(gui)磚是一(yi)種(zhong)特殊的(de)(de)材料，主(zhu)要應用(yong)(yong)與玻(bo)璃(li)(li)行(xing)業(ye)和(he)(he)(he)鋼鐵行(xing)業(ye)。在(zai)(zai)大部(bu)分情況下，輕質(zhi)(zhi)硅(gui)磚(zhuan)(zhuan)和(he)(he)(he)致密(mi)硅(gui)磚(zhuan)(zhuan)被(bei)用(yong)(yong)作結構(gou)層(ceng)(ceng)部(bu)分。常(chang)用(yong)(yong)的(de)(de)是玻(bo)璃(li)(li)窯(yao)(yao)行(xing)業(ye)，主(zhu)要是窯(yao)(yao)拱(gong)(gong)頂(ding)的(de)(de)隔(ge)熱(re)(re)，從而減少熱(re)(re)損失，增加熔融(rong)工藝的(de)(de)效率。在(zai)(zai)煉鋼行(xing)業(ye)輕質(zhi)(zhi)硅(gui)磚(zhuan)(zhuan)用(yong)(yong)于(yu)熱(re)(re)風(feng)(feng)爐(lu)(lu)墻體(ti)和(he)(he)(he)穹頂(ding)的(de)(de)輕質(zhi)(zhi)。 1、輕質(zhi)(zhi)硅(gui)磚(zhuan)(zhuan)用(yong)(yong)于(yu)玻(bo)璃(li)(li)行(xing)業(ye)—爐(lu)(lu)拱(gong)(gong)頂(ding)的(de)(de)隔(ge)熱(re)(re) 　　在(zai)(zai)玻(bo)璃(li)(li)熔融(rong)工藝中，在(zai)(zai)拱(gong)(gong)頂(ding)的(de)(de)凸起下部(bu)達到了很高的(de)(de)溫(wen)(wen)度(du)。根據玻(bo)璃(li)(li)的(de)(de)品種，溫(wen)(wen)度(du)在(zai)(zai)1600℃左右(you)。輕質(zhi)(zhi)層(ceng)(ceng)通(tong)常(chang)設計為(wei)(wei)兩(liang)層(ceng)(ceng)或更多層(ceng)(ceng)。 　　輕質(zhi)(zhi)硅(gui)磚(zhuan)(zhuan)主(zhu)要暴露(lu)在(zai)(zai)這(zhe)(zhe)些溫(wen)(wen)度(du)負(fu)荷下。期(qi)望拱(gong)(gong)頂(ding)（結構(gou)和(he)(he)(he)輕質(zhi)(zhi)層(ceng)(ceng)）單層(ceng)(ceng)具有相(xiang)同(tong)(tong)(tong)或相(xiang)似(si)膨(peng)脹性能(neng)。體(ti)積(ji)密(mi)度(du)為(wei)(wei)1250kg·m-3或1000kg·m-3的(de)(de)硅(gui)磚(zhuan)(zhuan)可(ke)以(yi)滿足致密(mi)層(ceng)(ceng)的(de)(de)要求。下一層(ceng)(ceng)使(shi)用(yong)(yong)體(ti)積(ji)密(mi)度(du)為(wei)(wei)800Kg·m-3或600kg·m-3的(de)(de)硅(gui)磚(zhuan)(zhuan)。 　　輕質(zhi)(zhi)硅(gui)磚(zhuan)(zhuan)可(ke)以(yi)碼在(zai)(zai)爐(lu)(lu)拱(gong)(gong)項上，或者用(yong)(yong)硅(gui)質(zhi)(zhi)火(huo)泥粘合。在(zai)(zai)爐(lu)(lu)役期(qi)（幾年）內沒有化學負(fu)荷。使(shi)用(yong)(yong)輕質(zhi)(zhi)硅(gui)磚(zhuan)(zhuan)，這(zhe)(zhe)是因為(wei)(wei)化學和(he)(he)(he)礦物組成工作襯所用(yong)(yong)的(de)(de)致密(mi)硅(gui)磚(zhuan)(zhuan)相(xiang)似(si)。 2、輕質(zhi)(zhi)硅(gui)磚(zhuan)(zhuan)用(yong)(yong)于(yu)鋼鐵行(xing)業(ye)-熱(re)(re)風(feng)(feng)爐(lu)(lu) 　　熱(re)(re)風(feng)(feng)爐(lu)(lu)常(chang)用(yong)(yong)于(yu)熱(re)(re)風(feng)(feng)（稱為(wei)(wei)高爐(lu)(lu)鼓風(feng)(feng)），這(zhe)(zhe)與高爐(lu)(lu)的(de)(de)抽氣(qi)機相(xiang)通(tong)，根據熱(re)(re)風(feng)(feng)爐(lu)(lu)的(de)(de)形狀(zhuang)和(he)(he)(he)部(bu)位不同(tong)(tong)(tong)，溫(wen)(wen)度(du)范圍(wei)在(zai)(zai)1000～1300℃之(zhi)間(jian)(jian)，熱(re)(re)空氣(qi)在(zai)(zai)2300～6500m3·min-1的(de)(de)范圍(wei)。 　　這(zhe)(zhe)需要計算出在(zai)(zai)不同(tong)(tong)(tong)水平和(he)(he)(he)各種負(fu)荷下熱(re)(re)風(feng)(feng)爐(lu)(lu)（組件尺寸和(he)(he)(he)使(shi)用(yong)(yong)部(bu)位不同(tong)(tong)(tong)）與玻(bo)璃(li)(li)窯(yao)(yao)拱(gong)(gong)頂(ding)之(zhi)間(jian)(jian)的(de)(de)熱機械(xie)性能上。對于(yu)輕(qing)質層，所(suo)用的(de)體積密度為(wei)1250kg·m-3或(huo)1050kg·m-3。