一、電解鋁為什么加入冰晶石
電解熔融氧化(hua)鋁是(shi)(shi)加冰晶石是(shi)(shi)為了降低電解液工作(zuo)溫度。
冰(bing)晶(jing)石(shi)(shi)熔(rong)點(dian)(dian)為(wei)(wei)1009℃,氧(yang)(yang)化(hua)鋁(lv)熔(rong)點(dian)(dian)為(wei)(wei)2050℃。冰(bing)晶(jing)石(shi)(shi)做(zuo)助熔(rong)劑(ji),熔(rong)融的冰(bing)晶(jing)石(shi)(shi)能溶解(jie)氧(yang)(yang)化(hua)鋁(lv),使(shi)得(de)電(dian)(dian)解(jie)可以在低(di)于(yu)氧(yang)(yang)化(hua)鋁(lv)的熔(rong)點(dian)(dian)溫度下工(gong)作,節約(yue)能源。電(dian)(dian)解(jie)熔(rong)融氧(yang)(yang)化(hua)鋁(lv)是(shi)加冰(bing)晶(jing)石(shi)(shi)是(shi)為(wei)(wei)了降低(di)電(dian)(dian)解(jie)液(ye)工(gong)作溫度。
PS:冰晶(jing)石(Cryolite)是一種(zhong)礦(kuang)物(wu),化學式為Na3AlF6,白(bai)色細小的結晶(jing)體,無氣(qi)味,在電解鋁工業(ye)作助熔劑、制造乳白(bai)色玻璃和搪瓷的遮(zhe)光劑。
二、電解鋁為什么用直流電
向(xiang)電(dian)(dian)(dian)解(jie)槽內(nei)通入直流電(dian)(dian)(dian),一(yi)方面是利用(yong)它的熱能(neng)將冰晶石熔化呈熔融狀態,并保持(chi)一(yi)定的電(dian)(dian)(dian)解(jie)溫度;另一(yi)方面主要的也是要在(zai)兩極實(shi)現(xian)電(dian)(dian)(dian)化學反應,也就是使電(dian)(dian)(dian)解(jie)質中的鋁離子從陰極上得到電(dian)(dian)(dian)子而(er)析(xi)出(chu),從而(er)得到鋁,氧離子則在(zai)陽(yang)極上放電(dian)(dian)(dian)與炭(tan)生成CO2、CO的混合氣體。
三、電解鋁為什么采用炭陽極
在(zai)鋁(lv)電(dian)解過程中,高(gao)溫(wen)且具有(you)很大侵蝕性的冰(bing)晶(jing)石熔液直接(jie)同電(dian)極(ji)接(jie)觸。作(zuo)(zuo)為(wei)導(dao)電(dian)的陰陽(yang)兩(liang)極(ji)的各種材(cai)料中,既能良(liang)好導(dao)電(dian),又能耐高(gao)溫(wen),抗(kang)腐蝕、同時價格又低廉的唯有(you)炭素(su)材(cai)料。因(yin)此(ci)鋁(lv)工業生(sheng)產都(dou)采用(yong)炭素(su)材(cai)料作(zuo)(zuo)兩(liang)極(ji)。