電熔鎂砂是生產堿性耐火材料不可或缺的原材料之一，在電熔鎂砂（電熔氧化鎂）的生產(chan)過(guo)程中，提(ti)高電熔凝(ning)氧化鎂的電學(xue)物理(li)性能的方法(fa)一般可采(cai)取下列四種途徑。

(1)熔(rong)煉過程中控制原料的(de)化學組(zu)成

氧(yang)(yang)化(hua)鎂原料中(zhong)的雜質如氧(yang)(yang)化(hua)鐵、氧(yang)(yang)化(hua)鉻、二氧(yang)(yang)化(hua)錳、氧(yang)(yang)化(hua)鈦、氧(yang)(yang)化(hua)鋁、氧(yang)(yang)化(hua)硅、氧(yang)(yang)化(hua)鈣等(deng)雜質對(dui)電(dian)熔凝氧(yang)(yang)化(hua)鎂的電(dian)學(xue)物理性質有重大的影響(xiang)。

亞(ya)鐵(tie)(tie)、氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)化(hua)(hua)(hua)(hua)鐵(tie)(tie)、二氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)化(hua)(hua)(hua)(hua)錳、氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)化(hua)(hua)(hua)(hua)鈦、氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)化(hua)(hua)(hua)(hua)鋁(lv)、氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)化(hua)(hua)(hua)(hua)鈣(gai)會(hui)降低(di)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)熔(rong)(rong)(rong)(rong)(rong)凝(ning)(ning)氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)化(hua)(hua)(hua)(hua)鎂(mei)(mei)(mei)(mei)的(de)(de)(de)絕(jue)(jue)緣電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻，或增(zeng)(zeng)大電(dian)(dian)(dian)(dian)(dian)(dian)(dian)熔(rong)(rong)(rong)(rong)(rong)凝(ning)(ning)氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)化(hua)(hua)(hua)(hua)鎂(mei)(mei)(mei)(mei)的(de)(de)(de)泄(xie)漏電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流，因而(er)各國對(dui)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)熔(rong)(rong)(rong)(rong)(rong)凝(ning)(ning)氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)化(hua)(hua)(hua)(hua)鎂(mei)(mei)(mei)(mei)中(zhong)這(zhe)些雜質(zhi)的(de)(de)(de)含量提(ti)出一定(ding)的(de)(de)(de)要求。據報道，氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)化(hua)(hua)(hua)(hua)鋁(lv)由于會(hui)同氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)化(hua)(hua)(hua)(hua)鎂(mei)(mei)(mei)(mei)形(xing)成高(gao)導電(dian)(dian)(dian)(dian)(dian)(dian)(dian)性(xing)能(neng)的(de)(de)(de)尖晶石(shi)(MgO·Al2O3)，使氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)化(hua)(hua)(hua)(hua)鎂(mei)(mei)(mei)(mei)的(de)(de)(de)介電(dian)(dian)(dian)(dian)(dian)(dian)(dian)性(xing)能(neng)變壞；氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)化(hua)(hua)(hua)(hua)鈣(gai)和氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)化(hua)(hua)(hua)(hua)硅若(ruo)能(neng)形(xing)成玻璃相(xiang)存在(zai)(zai)，在(zai)(zai)本(ben)質(zhi)上不(bu)會(hui)引起電(dian)(dian)(dian)(dian)(dian)(dian)(dian)熔(rong)(rong)(rong)(rong)(rong)凝(ning)(ning)氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)化(hua)(hua)(hua)(hua)鎂(mei)(mei)(mei)(mei)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)學(xue)(xue)物(wu)理性(xing)能(neng)的(de)(de)(de)改(gai)變，但氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)化(hua)(hua)(hua)(hua)鈣(gai)超過一定(ding)的(de)(de)(de)限(xian)量，會(hui)增(zeng)(zeng)加電(dian)(dian)(dian)(dian)(dian)(dian)(dian)熔(rong)(rong)(rong)(rong)(rong)凝(ning)(ning)氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)化(hua)(hua)(hua)(hua)鎂(mei)(mei)(mei)(mei)的(de)(de)(de)水化(hua)(hua)(hua)(hua)性(xing)，也(ye)會(hui)降低(di)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)熔(rong)(rong)(rong)(rong)(rong)凝(ning)(ning)氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)化(hua)(hua)(hua)(hua)鎂(mei)(mei)(mei)(mei)的(de)(de)(de)絕(jue)(jue)緣電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻值(zhi)，因而(er)也(ye)是應該加以限(xian)制(zhi)的(de)(de)(de)；氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)化(hua)(hua)(hua)(hua)鐵(tie)(tie)在(zai)(zai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)熔(rong)(rong)(rong)(rong)(rong)凝(ning)(ning)氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)化(hua)(hua)(hua)(hua)鎂(mei)(mei)(mei)(mei)中(zhong)的(de)(de)(de)存在(zai)(zai)對(dui)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)熔(rong)(rong)(rong)(rong)(rong)凝(ning)(ning)氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)化(hua)(hua)(hua)(hua)鎂(mei)(mei)(mei)(mei)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)學(xue)(xue)物(wu)理性(xing)質(zhi)的(de)(de)(de)影響，氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)化(hua)(hua)(hua)(hua)鐵(tie)(tie)在(zai)(zai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)熔(rong)(rong)(rong)(rong)(rong)凝(ning)(ning)氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)化(hua)(hua)(hua)(hua)鎂(mei)(mei)(mei)(mei)中(zhong)的(de)(de)(de)存在(zai)(zai)形(xing)式(shi)對(dui)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)熔(rong)(rong)(rong)(rong)(rong)凝(ning)(ning)氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)化(hua)(hua)(hua)(hua)鎂(mei)(mei)(mei)(mei)的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)學(xue)(xue)物(wu)理性(xing)質(zhi)如電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻，泄(xie)露(lu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流有重大影響，鐵(tie)(tie)若(ruo)以亞(ya)鐵(tie)(tie)形(xing)式(shi)存在(zai)(zai)，無疑會(hui)使電(dian)(dian)(dian)(dian)(dian)(dian)(dian)熔(rong)(rong)(rong)(rong)(rong)凝(ning)(ning)氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)化(hua)(hua)(hua)(hua)鎂(mei)(mei)(mei)(mei)的(de)(de)(de)絕(jue)(jue)緣電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻降低(di)，泄(xie)露(lu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流值(zhi)增(zeng)(zeng)大，若(ruo)鐵(tie)(tie)以高(gao)價鐵(tie)(tie)的(de)(de)(de)某(mou)些復合物(wu)形(xing)式(shi)存在(zai)(zai)于電(dian)(dian)(dian)(dian)(dian)(dian)(dian)熔(rong)(rong)(rong)(rong)(rong)凝(ning)(ning)氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)化(hua)(hua)(hua)(hua)鎂(mei)(mei)(mei)(mei)中(zhong)，相(xiang)反也(ye)會(hui)使電(dian)(dian)(dian)(dian)(dian)(dian)(dian)熔(rong)(rong)(rong)(rong)(rong)凝(ning)(ning)氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)化(hua)(hua)(hua)(hua)鎂(mei)(mei)(mei)(mei)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)學(xue)(xue)物(wu)理性(xing)質(zhi)變好，如電(dian)(dian)(dian)(dian)(dian)(dian)(dian)絕(jue)(jue)緣阻增(zeng)(zeng)大，泄(xie)露(lu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流值(zhi)降低(di)。

(2)對電熔(rong)凝氧化鎂產品進行(xing)磁選

在電(dian)熔凝氧(yang)化鎂(mei)塊經過破碎加工的過程中(zhong)(zhong)，不可(ke)避免地會帶入(ru)部分機械(xie)金屬雜(za)質(zhi)，也可(ke)能在氧(yang)化鎂(mei)中(zhong)(zhong)本(ben)身含有鎂(mei)富(fu)氏體等磁體物質(zhi)。這些有害(hai)雜(za)質(zhi)，可(ke)通(tong)過磁選(xuan)加以除去，磁選(xuan)中(zhong)(zhong)一般應采(cai)用(yong)兩(liang)段磁選(xuan)法。

(3)電熔凝氧化(hua)鎂(mei)砂的煅燒熱(re)處理

電(dian)熔(rong)凝氧化鎂砂(sha)(sha)晶粒的表面(mian)(mian)(mian)狀況決定著它(ta)的水化程(cheng)度。晶粒表面(mian)(mian)(mian)的缺陷、裂紋、損(sun)傷、擦(ca)痕等使晶體的比表面(mian)(mian)(mian)積增大，從(cong)而提高了氧化鎂的吸濕性，降低絕緣電(dian)阻值(zhi)。通過(guo)對鎂砂(sha)(sha)的熱處理(li)，可以改(gai)善鎂砂(sha)(sha)的吸水性。

鎂(mei)砂(sha)通過(guo)熱處(chu)理(li)后，它(ta)的(de)防吸濕性可(ke)(ke)以(yi)得到改(gai)善(shan)，因(yin)此，這一措施可(ke)(ke)以(yi)改(gai)善(shan)電(dian)(dian)(dian)(dian)(dian)熔凝氧化(hua)(hua)鎂(mei)砂(sha)的(de)電(dian)(dian)(dian)(dian)(dian)性能質量。通過(guo)對電(dian)(dian)(dian)(dian)(dian)熔凝氧化(hua)(hua)鎂(mei)砂(sha)的(de)熱處(chu)理(li)，不僅可(ke)(ke)以(yi)改(gai)善(shan)鎂(mei)砂(sha)的(de)表面狀況，而(er)且可(ke)(ke)以(yi)除(chu)(chu)去(qu)電(dian)(dian)(dian)(dian)(dian)熔過(guo)程(cheng)中(zhong)進入電(dian)(dian)(dian)(dian)(dian)熔凝氧化(hua)(hua)鎂(mei)中(zhong)的(de)碳(tan)(tan)。據有(you)關工廠的(de)測試，電(dian)(dian)(dian)(dian)(dian)弧爐帶(dai)入熔體的(de)碳(tan)(tan)量比感應爐多(duo)27倍，在氧化(hua)(hua)氣氛下進行(xing)熱處(chu)理(li)可(ke)(ke)以(yi)除(chu)(chu)去(qu)碳(tan)(tan)，同(tong)時也可(ke)(ke)以(yi)改(gai)變電(dian)(dian)(dian)(dian)(dian)熔凝氧化(hua)(hua)鎂(mei)中(zhong)鐵的(de)價態(tai)，即使(shi)鐵由還(huan)原(yuan)態(tai)變成氧化(hua)(hua)態(tai)，可(ke)(ke)使(shi)晶形(xing)發(fa)生改(gai)變，因(yin)而(er)可(ke)(ke)使(shi)原(yuan)電(dian)(dian)(dian)(dian)(dian)熔凝氧化(hua)(hua)鎂(mei)的(de)熱態(tai)絕緣(yuan)電(dian)(dian)(dian)(dian)(dian)阻增大(da)。據報(bao)道，在還(huan)原(yuan)性氣氛中(zhong)進行(xing)熱處(chu)理(li)，可(ke)(ke)促進硅酸(suan)(suan)鹽蒸發(fa)，在真(zhen)空中(zhong)進行(xing)熱處(chu)理(li)，可(ke)(ke)除(chu)(chu)去(qu)氯化(hua)(hua)物(wu)、硫的(de)化(hua)(hua)合物(wu)、碳(tan)(tan)和某(mou)些硅酸(suan)(suan)鹽，或(huo)者使(shi)它(ta)們向(xiang)另一狀態(tai)改(gai)變。這些都有(you)利于提高鎂(mei)砂(sha)的(de)質量。

(4)加入添加劑

電熔凝氧化鎂生產過程中，為了提高氧化鎂的電學物理性質，往往在電熔氧化鎂中加(jia)(jia)入(ru)(ru)某些添加(jia)(jia)劑。據(ju)報道，可加(jia)(jia)入(ru)(ru)的(de)添加(jia)(jia)劑有層狀(zhuang)硅酸(suan)鹽、硼(peng)和鋁的(de)氧(yang)化(hua)物、稀土金屬(shu)氧(yang)化(hua)物、氧(yang)化(hua)鋇等(deng)。加(jia)(jia)入(ru)(ru)添加(jia)(jia)劑的(de)作用是(shi)促(cu)使氧(yang)化(hua)鎂(mei)質點致密化(hua)，有的(de)添加(jia)(jia)劑質點可進入(ru)(ru)氧(yang)化(hua)鎂(mei)晶(jing)(jing)格，降低(di)晶(jing)(jing)體空穴的(de)濃度，阻礙空穴導電，使氧(yang)化(hua)鎂(mei)砂的(de)導電率(lv)降低(di)。

在(zai)電熔(rong)凝氧化鎂(mei)中加(jia)(jia)入(ru)(ru)添(tian)加(jia)(jia)劑(ji)的(de)方法有兩(liang)種(zhong)，一種(zhong)是熔(rong)融加(jia)(jia)入(ru)(ru)法，把(ba)添(tian)加(jia)(jia)劑(ji)按一定的(de)比例加(jia)(jia)入(ru)(ru)原料氧化鎂(mei)中進行電熔(rong)，在(zai)熔(rong)體中引入(ru)(ru)了添(tian)加(jia)(jia)劑(ji)；另一種(zhong)方法是在(zai)電熔(rong)鎂(mei)砂(sha)中直(zhi)接機(ji)械混入(ru)(ru)添(tian)加(jia)(jia)劑(ji)微粒，通過拌和混勻獲得(de)產品(pin)，或者用(yong)有機(ji)硅化物處理電熔(rong)氧化鎂(mei)砂(sha)制的(de)憎水性電熔(rong)氧化鎂(mei)砂(sha)。