廈門電熔鎂砂是重(zhong)要的(de)工(gong)業(ye)原(yuan)材料(liao)，其生(sheng)產工(gong)藝簡單(dan)，主(zhu)要以氧化鎂壓球料(liao)為原(yuan)料(liao)，采用電(dian)弧爐熔融法制(zhi)備(bei)而成(cheng)(cheng)。我國電(dian)熔鎂砂制(zhi)備(bei)工(gong)藝技術方面的(de)研究(jiu)成(cheng)(cheng)果，主(zhu)要表現(xian)在選擇適(shi)宜的(de)化學添(tian)加(jia)劑改善鎂砂的(de)性能以及高效(xiao)新(xin)工(gong)藝的(de)開發。

我(wo)國電(dian)熔鎂砂制備工(gong)藝(yi)及應(ying)用

      我國電(dian)熔(rong)(rong)鎂(mei)(mei)(mei)砂制(zhi)備(bei)優化工藝。當(dang)前(qian)我國電(dian)熔(rong)(rong)鎂(mei)(mei)(mei)產業(ye)仍在(zai)沿用電(dian)弧爐生產方式(shi)(shi)，技術(shu)(shu)裝備(bei)相對落后，效率(lv)低，能源浪費嚴(yan)(yan)重(zhong)(zhong)，余熱潛能流失嚴(yan)(yan)重(zhong)(zhong);電(dian)熔(rong)(rong)鎂(mei)(mei)(mei)砂生產過程(cheng)中還存(cun)在(zai)著嚴(yan)(yan)重(zhong)(zhong)的粉塵(chen)污染，并大(da)量排放(fang)二氧化碳，加重(zhong)(zhong)了大(da)氣溫室效應，惡化周(zhou)邊環境。現(xian)有(you)電(dian)熔(rong)(rong)鎂(mei)(mei)(mei)技術(shu)(shu)裝備(bei)亟待更新換代(dai)，現(xian)有(you)工藝急需創新，因此，采(cai)用集成技術(shu)(shu)發展節能環保的新式(shi)(shi)電(dian)熔(rong)(rong)鎂(mei)(mei)(mei)裝備(bei)及制(zhi)備(bei)工藝是發展電(dian)熔(rong)(rong)鎂(mei)(mei)(mei)產業(ye)的重(zhong)(zhong)要選擇(ze)。

      近年來(lai)，國內的(de)(de)(de)科技工(gong)(gong)作者在(zai)電(dian)熔(rong)鎂(mei)(mei)砂(sha)的(de)(de)(de)生產(chan)工(gong)(gong)藝(yi)(yi)方面進(jin)行了改(gai)進(jin)和(he)優(you)化(hua)(hua)(hua)(hua)，并取(qu)得了一定的(de)(de)(de)成(cheng)效。電(dian)熔(rong)鎂(mei)(mei)砂(sha)的(de)(de)(de)生產(chan)工(gong)(gong)藝(yi)(yi)流(liu)程短而簡單，但設(she)備(bei)投入和(he)資源(yuan)消耗大。我(wo)國電(dian)熔(rong)鎂(mei)(mei)砂(sha)產(chan)業多采用(yong)電(dian)弧爐熔(rong)融天然菱鎂(mei)(mei)礦石制備(bei)電(dian)熔(rong)鎂(mei)(mei)砂(sha)，生產(chan)工(gong)(gong)藝(yi)(yi)技術裝備(bei)落后，功率(lv)低(di)(di)、容量小(xiao)、效率(lv)低(di)(di)、自動化(hua)(hua)(hua)(hua)程度(du)低(di)(di)，生產(chan)出的(de)(de)(de)電(dian)熔(rong)鎂(mei)(mei)砂(sha)產(chan)品品位不高，導致(zhi)鎂(mei)(mei)資源(yuan)利(li)用(yong)率(lv)低(di)(di)，環境污染嚴重。通過(guo)利(li)用(yong)鹽(yan)湖(hu)鹵水與氨(an)氣反應(ying)后生成(cheng)氫氧化(hua)(hua)(hua)(hua)鎂(mei)(mei)在(zai)煅(duan)燒后生成(cheng)輕質(zhi)氧化(hua)(hua)(hua)(hua)鎂(mei)(mei)，可(ke)以通過(guo)洗(xi)滌、過(guo)濾等方法有效地除去雜質(zhi)離子，氧化(hua)(hua)(hua)(hua)鎂(mei)(mei)的(de)(de)(de)純度(du)高達99.9%，在(zai)較低(di)(di)溫度(du)下輕燒得氧化(hua)(hua)(hua)(hua)鎂(mei)(mei)粉(fen)末，而后經一定壓力壓球，制取(qu)高純電(dian)熔(rong)鎂(mei)(mei)砂(sha)。

電熔鎂砂熔煉過程研究

      電(dian)(dian)(dian)(dian)(dian)(dian)(dian)熔(rong)鎂(mei)砂熔(rong)煉工藝原理。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)熔(rong)鎂(mei)砂是(shi)采用(yong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)弧熔(rong)融法進行(xing)制備，其裝備是(shi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)熔(rong)鎂(mei)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)弧爐(礦熱(re)(re)(re)埋弧電(dian)(dian)(dian)(dian)(dian)(dian)(dian)爐)，即通過電(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)的埋弧電(dian)(dian)(dian)(dian)(dian)(dian)(dian)熱(re)(re)(re)和物(wu)料的電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)熱(re)(re)(re)來熔(rong)煉物(wu)料。其電(dian)(dian)(dian)(dian)(dian)(dian)(dian)耗很大，爐體(ti)一般呈圓形(xing)，三根電(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)布置(zhi)成(cheng)三角(jiao)形(xing)。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)熔(rong)鎂(mei)爐在生產過程中(zhong)，是(shi)以電(dian)(dian)(dian)(dian)(dian)(dian)(dian)弧電(dian)(dian)(dian)(dian)(dian)(dian)(dian)熱(re)(re)(re)對(dui)爐料加熱(re)(re)(re)使之(zhi)熔(rong)化，形(xing)成(cheng)熔(rong)池(chi)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)弧電(dian)(dian)(dian)(dian)(dian)(dian)(dian)熱(re)(re)(re)越大，物(wu)料熔(rong)化的速度越快。

      電(dian)熔(rong)鎂(mei)砂的制備(bei)是以氫(qing)氧化(hua)(hua)鎂(mei)煅(duan)燒氧化(hua)(hua)鎂(mei)壓制成球后(hou)(hou)為原(yuan)料(liao)，在(zai)4000kVA高溫(wen)電(dian)弧(hu)爐(lu)(lu)中經冶煉(lian)、熔(rong)化(hua)(hua)再(zai)結晶(jing)(jing)后(hou)(hou)形成的鎂(mei)砂制品，在(zai)不同類型的電(dian)弧(hu)爐(lu)(lu)中通過電(dian)弧(hu)加熱(re)產(chan)生高溫(wen)(≥2800℃)，使鎂(mei)質原(yuan)料(liao)在(zai)爐(lu)(lu)中受熱(re)、脫水(釆用水氯鎂(mei)石)、溶融、析晶(jing)(jing)、晶(jing)(jing)體(ti)長大(da)(da)、冷卻等一系列物(wu)理化(hua)(hua)學(xue)變化(hua)(hua)過程，形成一種耐(nai)高溫(wen)、硬(ying)度大(da)(da)、純度高的電(dian)熔(rong)氧化(hua)(hua)鎂(mei)晶(jing)(jing)體(ti)。

      電(dian)(dian)熔鎂砂的(de)熔煉(lian)過(guo)程主要分為填(tian)料(liao)(liao)階(jie)(jie)(jie)段(duan)(duan)、起弧(hu)(hu)階(jie)(jie)(jie)段(duan)(duan)、熔融(rong)階(jie)(jie)(jie)段(duan)(duan)、加料(liao)(liao)階(jie)(jie)(jie)段(duan)(duan)、冷(leng)卻階(jie)(jie)(jie)段(duan)(duan)以及停爐階(jie)(jie)(jie)段(duan)(duan)：填(tian)料(liao)(liao)階(jie)(jie)(jie)段(duan)(duan)。在電(dian)(dian)熔開始工(gong)作之前需往爐內裝(zhuang)料(liao)(liao)，應做到將(jiang)料(liao)(liao)壓實壓密，并在粉料(liao)(liao)的(de)最上層鋪一(yi)層工(gong)業冶(ye)金焦炭，其平鋪范圍在三根電(dian)(dian)極(ji)所形成(cheng)的(de)三角形范圍內，使得起弧(hu)(hu)后電(dian)(dian)路形成(cheng)回路;起弧(hu)(hu)階(jie)(jie)(jie)段(duan)(duan)。調節電(dian)(dian)極(ji)，開始進入起弧(hu)(hu)階(jie)(jie)(jie)段(duan)(duan);熔融(rong)階(jie)(jie)(jie)段(duan)(duan)。起弧(hu)(hu)后，待(dai)電(dian)(dian)流趨于平穩后，電(dian)(dian)極(ji)周圍的(de)原料(liao)(liao)開始熔融(rong)，熔池逐漸形成(cheng);加料(liao)(liao)階(jie)(jie)(jie)段(duan)(duan)。

      隨氧(yang)化(hua)(hua)(hua)(hua)鎂原料不斷消(xiao)耗(hao)，熔(rong)(rong)池(chi)液(ye)面開始下降，待熔(rong)(rong)池(chi)穩(wen)定后可往(wang)(wang)電(dian)(dian)極周圍填料，進(jin)入(ru)加料階段(需(xu)注意(yi)不要破(po)壞熔(rong)(rong)池(chi)的穩(wen)定性);冷(leng)卻階段。熔(rong)(rong)煉完成后，電(dian)(dian)極逐(zhu)漸被氧(yang)化(hua)(hua)(hua)(hua)消(xiao)耗(hao)，電(dian)(dian)流減小。需(xu)通過冷(leng)卻給熔(rong)(rong)池(chi)內的氧(yang)化(hua)(hua)(hua)(hua)鎂晶體創(chuang)造(zao)一個穩(wen)定散熱降溫的環境，使其冷(leng)凝(ning)結晶出多晶氧(yang)化(hua)(hua)(hua)(hua)鎂產品;停爐階段。停爐過程(cheng)中，往(wang)(wang)往(wang)(wang)采(cai)用手動加料，為(wei)了減少排(pai)氣，電(dian)(dian)極附近(jin)要加入(ru)氧(yang)化(hua)(hua)(hua)(hua)鎂坯(pi)砂(sha)(氧(yang)化(hua)(hua)(hua)(hua)鎂輕燒粉不含CO2)，并多加細粉料，有(you)利于(yu)產品產量(liang)及(ji)品質提高。電(dian)(dian)熔(rong)(rong)鎂砂(sha)熔(rong)(rong)融結晶過程(cheng)。

      電熔(rong)鎂(mei)砂的(de)熔(rong)融結(jie)晶過程(cheng)伴隨(sui)著雜(za)質(zhi)的(de)遷(qian)移(yi)(yi)和析出(chu)，在熔(rong)煉過程(cheng)中，由(you)于各組分的(de)熔(rong)點(dian)(dian)和密度(du)不同，其析出(chu)方(fang)式存在差異：熔(rong)融開始時，隨(sui)溫度(du)的(de)升(sheng)高，熔(rong)點(dian)(dian)較低的(de)雜(za)質(zhi)先達到(dao)熔(rong)點(dian)(dian)溫度(du)，并轉變成(cheng)液態(tai);隨(sui)溫度(du)繼續升(sheng)高，當達到(dao)氧(yang)(yang)化(hua)鎂(mei)熔(rong)點(dian)(dian)溫度(du)時，此時氧(yang)(yang)化(hua)鎂(mei)開始熔(rong)化(hua)，因氧(yang)(yang)化(hua)鎂(mei)的(de)密度(du)相對(dui)較高，其它雜(za)質(zhi)的(de)密度(du)相對(dui)較低，加上熔(rong)池中二(er)氧(yang)(yang)化(hua)碳和水蒸氣的(de)不斷上升(sheng)，使得雜(za)質(zhi)逐漸(jian)向上遷(qian)移(yi)(yi)。

      總之，目前(qian)電(dian)熔鎂(mei)砂(sha)傳統(tong)生(sheng)(sheng)(sheng)產(chan)工藝是(shi)(shi)以菱鎂(mei)礦為原料(liao)，通過電(dian)弧爐高(gao)溫熔煉制(zhi)備(bei)而(er)(er)成，但(dan)該法存在產(chan)品(pin)質(zhi)量不高(gao)、生(sheng)(sheng)(sheng)產(chan)能耗高(gao)、環境污染嚴重、工作強度大(da)等(deng)(deng)缺陷。而(er)(er)利用鹽湖(hu)鹵水制(zhi)備(bei)的(de)高(gao)純(chun)(chun)Mg(OH)2中間(jian)體(ti)為原料(liao)生(sheng)(sheng)(sheng)產(chan)高(gao)純(chun)(chun)電(dian)熔鎂(mei)砂(sha)，具有產(chan)品(pin)附(fu)加值高(gao)、生(sheng)(sheng)(sheng)產(chan)處理量大(da)、能耗低等(deng)(deng)優異特(te)點，解決了(le)國內(nei)外高(gao)端(duan)鎂(mei)砂(sha)制(zhi)品(pin)的(de)需求。因此，該工藝是(shi)(shi)今后高(gao)純(chun)(chun)電(dian)熔鎂(mei)砂(sha)制(zhi)備(bei)的(de)主(zhu)流方向(xiang)。

電熔鎂砂