生產石膏的原料主要為含硫酸鈣的天然石膏（又稱生石膏）或含硫酸鈣的化工副產品和磷石膏、氟石膏、硼石膏等廢渣，其化學式為CaSO4.1/2H2O，也稱半水石膏。將天然二水石膏在不同的溫度下煅燒可得到不同的石膏品種。如將天然二水石膏在107~170℃的干燥條件下加熱可得海南建筑石膏。

將建(jian)(jian)筑(zhu)(zhu)石(shi)膏加水(shui)(shui)(shui)后，它首(shou)先(xian)(xian)溶解于水(shui)(shui)(shui)，然后生(sheng)(sheng)(sheng)成(cheng)二水(shui)(shui)(shui)石(shi)膏析出。隨著水(shui)(shui)(shui)化(hua)(hua)的(de)不(bu)斷進(jin)行，生(sheng)(sheng)(sheng)成(cheng)的(de)二水(shui)(shui)(shui)石(shi)膏膠體(ti)(ti)(ti)(ti)微粒(li)不(bu)斷增(zeng)多，這(zhe)些微粒(li)比(bi)原(yuan)先(xian)(xian)更加細小(xiao)，比(bi)表面(mian)積(ji)很大，吸附著很多的(de)水(shui)(shui)(shui)分(fen)；同時漿(jiang)(jiang)體(ti)(ti)(ti)(ti)中的(de)自由水(shui)(shui)(shui)分(fen)由于水(shui)(shui)(shui)化(hua)(hua)和(he)蒸發而不(bu)斷減(jian)少，漿(jiang)(jiang)體(ti)(ti)(ti)(ti)的(de)稠度(du)不(bu)斷增(zeng)加，膠體(ti)(ti)(ti)(ti)微粒(li)間的(de)黏(nian)結(jie)逐步增(zeng)強(qiang)(qiang)，顆粒(li)間產(chan)(chan)(chan)生(sheng)(sheng)(sheng)摩擦(ca)力和(he)黏(nian)結(jie)力，使漿(jiang)(jiang)體(ti)(ti)(ti)(ti)逐漸失去(qu)(qu)可(ke)塑(su)性，即漿(jiang)(jiang)體(ti)(ti)(ti)(ti)逐漸產(chan)(chan)(chan)生(sheng)(sheng)(sheng)凝結(jie)。繼續(xu)水(shui)(shui)(shui)化(hua)(hua)，膠體(ti)(ti)(ti)(ti)轉變成(cheng)晶體(ti)(ti)(ti)(ti)。晶體(ti)(ti)(ti)(ti)顆粒(li)逐漸長大，使漿(jiang)(jiang)體(ti)(ti)(ti)(ti)完(wan)全失去(qu)(qu)可(ke)塑(su)性，產(chan)(chan)(chan)生(sheng)(sheng)(sheng)強(qiang)(qiang)度(du)，即漿(jiang)(jiang)體(ti)(ti)(ti)(ti)產(chan)(chan)(chan)生(sheng)(sheng)(sheng)了硬化(hua)(hua)。這(zhe)一過程(cheng)不(bu)斷進(jin)行，直至漿(jiang)(jiang)體(ti)(ti)(ti)(ti)完(wan)全干燥，強(qiang)(qiang)度(du)不(bu)在增(zeng)加，此時漿(jiang)(jiang)體(ti)(ti)(ti)(ti)已硬化(hua)(hua)成(cheng)人(ren)造石(shi)材(cai)。石(shi)膏砌塊是(shi)以建(jian)(jian)筑(zhu)(zhu)石(shi)膏為主要原(yuan)材(cai)料，經加水(shui)(shui)(shui)攪(jiao)拌、澆注成(cheng)型(xing)(xing)和(he)干燥制(zhi)成(cheng)的(de)輕質建(jian)(jian)筑(zhu)(zhu)石(shi)膏制(zhi)品。生(sheng)(sheng)(sheng)產(chan)(chan)(chan)中允許加入纖維增(zeng)強(qiang)(qiang)材(cai)料或輕集(ji)料，也(ye)可(ke)加入發泡(pao)劑。石(shi)膏砌塊具有隔聲防火、施(shi)工(gong)便捷(jie)等(deng)多項優點，是(shi)一種低碳(tan)環保、健康、符合時代(dai)發展要求的(de)新型(xing)(xing)墻體(ti)(ti)(ti)(ti)材(cai)料。