文昌電熔鎂砂是重要(yao)的工業原材料(liao)，其生(sheng)產(chan)工藝簡單，主要(yao)以氧化鎂壓球料(liao)為原料(liao)，采用電(dian)弧爐熔融法制備(bei)而成(cheng)。我(wo)國(guo)電(dian)熔鎂砂制備(bei)工藝技(ji)術方面的研究成(cheng)果(guo)，主要(yao)表現在選擇適宜的化學添加劑改(gai)善鎂砂的性能以及高(gao)效新工藝的開發。

我國(guo)電熔鎂砂制備工藝(yi)及應用

      我國電(dian)(dian)(dian)熔(rong)鎂砂制備(bei)優化工(gong)藝。當前(qian)我國電(dian)(dian)(dian)熔(rong)鎂產(chan)業仍在沿用電(dian)(dian)(dian)弧爐生產(chan)方(fang)式，技(ji)(ji)術(shu)裝(zhuang)備(bei)相(xiang)對(dui)落后，效率低，能源浪費嚴重(zhong)，余熱(re)潛能流失嚴重(zhong);電(dian)(dian)(dian)熔(rong)鎂砂生產(chan)過程中還(huan)存在著嚴重(zhong)的(de)(de)粉塵污染，并大量排放二氧化碳，加重(zhong)了(le)大氣(qi)溫室(shi)效應，惡(e)化周(zhou)邊環境(jing)。現(xian)有電(dian)(dian)(dian)熔(rong)鎂技(ji)(ji)術(shu)裝(zhuang)備(bei)亟(ji)待更新換代，現(xian)有工(gong)藝急需創新，因此，采用集(ji)成技(ji)(ji)術(shu)發(fa)展節能環保的(de)(de)新式電(dian)(dian)(dian)熔(rong)鎂裝(zhuang)備(bei)及制備(bei)工(gong)藝是發(fa)展電(dian)(dian)(dian)熔(rong)鎂產(chan)業的(de)(de)重(zhong)要選擇。

      近年來，國(guo)內的(de)科技工作者(zhe)在電熔(rong)(rong)鎂(mei)(mei)(mei)砂的(de)生(sheng)產(chan)(chan)工藝(yi)方(fang)面進行(xing)了改進和優(you)化(hua)，并取得(de)了一(yi)定的(de)成效(xiao)。電熔(rong)(rong)鎂(mei)(mei)(mei)砂的(de)生(sheng)產(chan)(chan)工藝(yi)流程短而簡單，但設備投(tou)入和資(zi)源(yuan)消耗大。我國(guo)電熔(rong)(rong)鎂(mei)(mei)(mei)砂產(chan)(chan)業多采用(yong)電弧爐熔(rong)(rong)融(rong)天然菱鎂(mei)(mei)(mei)礦石制(zhi)備電熔(rong)(rong)鎂(mei)(mei)(mei)砂，生(sheng)產(chan)(chan)工藝(yi)技術裝備落后(hou)，功率低(di)、容(rong)量(liang)小(xiao)、效(xiao)率低(di)、自(zi)動化(hua)程度低(di)，生(sheng)產(chan)(chan)出的(de)電熔(rong)(rong)鎂(mei)(mei)(mei)砂產(chan)(chan)品品位不高，導致鎂(mei)(mei)(mei)資(zi)源(yuan)利用(yong)率低(di)，環境污(wu)染嚴(yan)重。通過利用(yong)鹽湖鹵水與氨氣反應后(hou)生(sheng)成氫氧(yang)(yang)化(hua)鎂(mei)(mei)(mei)在煅燒(shao)后(hou)生(sheng)成輕質氧(yang)(yang)化(hua)鎂(mei)(mei)(mei)，可以通過洗滌、過濾(lv)等方(fang)法有效(xiao)地除去雜質離子，氧(yang)(yang)化(hua)鎂(mei)(mei)(mei)的(de)純度高達99.9%，在較(jiao)低(di)溫(wen)度下輕燒(shao)得(de)氧(yang)(yang)化(hua)鎂(mei)(mei)(mei)粉末，而后(hou)經一(yi)定壓力(li)壓球，制(zhi)取高純電熔(rong)(rong)鎂(mei)(mei)(mei)砂。

電(dian)熔鎂砂熔煉過(guo)程(cheng)研究

      電(dian)(dian)(dian)(dian)熔(rong)(rong)鎂砂熔(rong)(rong)煉工藝原理(li)。電(dian)(dian)(dian)(dian)熔(rong)(rong)鎂砂是(shi)采(cai)用電(dian)(dian)(dian)(dian)弧熔(rong)(rong)融(rong)法進行(xing)制備，其(qi)裝備是(shi)電(dian)(dian)(dian)(dian)熔(rong)(rong)鎂電(dian)(dian)(dian)(dian)弧爐(lu)(礦熱(re)埋(mai)(mai)弧電(dian)(dian)(dian)(dian)爐(lu))，即通過(guo)(guo)電(dian)(dian)(dian)(dian)極的(de)(de)埋(mai)(mai)弧電(dian)(dian)(dian)(dian)熱(re)和物料的(de)(de)電(dian)(dian)(dian)(dian)阻電(dian)(dian)(dian)(dian)熱(re)來(lai)熔(rong)(rong)煉物料。其(qi)電(dian)(dian)(dian)(dian)耗很大，爐(lu)體一般(ban)呈圓(yuan)形，三根電(dian)(dian)(dian)(dian)極布置成三角形。電(dian)(dian)(dian)(dian)熔(rong)(rong)鎂爐(lu)在生產過(guo)(guo)程(cheng)中，是(shi)以(yi)電(dian)(dian)(dian)(dian)弧電(dian)(dian)(dian)(dian)熱(re)對爐(lu)料加熱(re)使之熔(rong)(rong)化，形成熔(rong)(rong)池，電(dian)(dian)(dian)(dian)弧電(dian)(dian)(dian)(dian)熱(re)越大，物料熔(rong)(rong)化的(de)(de)速(su)度(du)越快(kuai)。

      電(dian)熔(rong)鎂(mei)砂的制備是以氫氧(yang)化(hua)(hua)鎂(mei)煅燒氧(yang)化(hua)(hua)鎂(mei)壓制成(cheng)球后(hou)為原料，在(zai)4000kVA高(gao)溫(wen)電(dian)弧(hu)爐中(zhong)經(jing)冶煉、熔(rong)化(hua)(hua)再結晶(jing)后(hou)形成(cheng)的鎂(mei)砂制品，在(zai)不(bu)同類型(xing)的電(dian)弧(hu)爐中(zhong)通過(guo)電(dian)弧(hu)加熱(re)產生高(gao)溫(wen)(≥2800℃)，使鎂(mei)質(zhi)原料在(zai)爐中(zhong)受熱(re)、脫水(釆用水氯(lv)鎂(mei)石(shi))、溶融、析晶(jing)、晶(jing)體(ti)長大、冷卻等一(yi)系列(lie)物理化(hua)(hua)學變化(hua)(hua)過(guo)程(cheng)，形成(cheng)一(yi)種(zhong)耐高(gao)溫(wen)、硬度大、純度高(gao)的電(dian)熔(rong)氧(yang)化(hua)(hua)鎂(mei)晶(jing)體(ti)。

      電(dian)熔(rong)(rong)鎂砂的(de)(de)熔(rong)(rong)煉(lian)過程主要分為填(tian)料(liao)(liao)(liao)階(jie)(jie)(jie)段(duan)(duan)(duan)、起(qi)弧(hu)階(jie)(jie)(jie)段(duan)(duan)(duan)、熔(rong)(rong)融(rong)階(jie)(jie)(jie)段(duan)(duan)(duan)、加料(liao)(liao)(liao)階(jie)(jie)(jie)段(duan)(duan)(duan)、冷卻階(jie)(jie)(jie)段(duan)(duan)(duan)以(yi)及停爐階(jie)(jie)(jie)段(duan)(duan)(duan)：填(tian)料(liao)(liao)(liao)階(jie)(jie)(jie)段(duan)(duan)(duan)。在電(dian)熔(rong)(rong)開始(shi)工(gong)作之前需往爐內裝料(liao)(liao)(liao)，應做(zuo)到將(jiang)料(liao)(liao)(liao)壓(ya)實壓(ya)密，并在粉料(liao)(liao)(liao)的(de)(de)最(zui)上層鋪一層工(gong)業冶金焦炭，其平鋪范(fan)圍(wei)在三根電(dian)極所(suo)形成(cheng)的(de)(de)三角形范(fan)圍(wei)內，使得起(qi)弧(hu)后電(dian)路形成(cheng)回(hui)路;起(qi)弧(hu)階(jie)(jie)(jie)段(duan)(duan)(duan)。調節(jie)電(dian)極，開始(shi)進入(ru)起(qi)弧(hu)階(jie)(jie)(jie)段(duan)(duan)(duan);熔(rong)(rong)融(rong)階(jie)(jie)(jie)段(duan)(duan)(duan)。起(qi)弧(hu)后，待電(dian)流趨于平穩后，電(dian)極周圍(wei)的(de)(de)原(yuan)料(liao)(liao)(liao)開始(shi)熔(rong)(rong)融(rong)，熔(rong)(rong)池逐(zhu)漸形成(cheng);加料(liao)(liao)(liao)階(jie)(jie)(jie)段(duan)(duan)(duan)。

      隨氧(yang)化鎂(mei)(mei)(mei)原(yuan)料(liao)不(bu)斷消耗，熔(rong)池液面開始(shi)下降，待熔(rong)池穩定(ding)后可往電(dian)(dian)極周圍填料(liao)，進入(ru)加料(liao)階段(需(xu)(xu)注(zhu)意不(bu)要(yao)破壞熔(rong)池的穩定(ding)性);冷卻階段。熔(rong)煉(lian)完(wan)成后，電(dian)(dian)極逐漸被氧(yang)化消耗，電(dian)(dian)流減小。需(xu)(xu)通過(guo)冷卻給(gei)熔(rong)池內的氧(yang)化鎂(mei)(mei)(mei)晶體創造一(yi)個穩定(ding)散(san)熱(re)降溫的環境，使其(qi)冷凝結(jie)晶出(chu)多晶氧(yang)化鎂(mei)(mei)(mei)產品;停爐階段。停爐過(guo)程中，往往采用手(shou)動加料(liao)，為了減少(shao)排氣，電(dian)(dian)極附近要(yao)加入(ru)氧(yang)化鎂(mei)(mei)(mei)坯砂(氧(yang)化鎂(mei)(mei)(mei)輕燒粉不(bu)含CO2)，并多加細(xi)粉料(liao)，有利(li)于產品產量及品質(zhi)提高。電(dian)(dian)熔(rong)鎂(mei)(mei)(mei)砂熔(rong)融結(jie)晶過(guo)程。

      電(dian)熔(rong)(rong)鎂(mei)(mei)(mei)砂的(de)(de)(de)熔(rong)(rong)融結晶過程伴隨(sui)(sui)著雜質(zhi)(zhi)(zhi)的(de)(de)(de)遷移和析出(chu)，在熔(rong)(rong)煉過程中，由于各組分(fen)的(de)(de)(de)熔(rong)(rong)點(dian)和密度(du)不(bu)同(tong)，其析出(chu)方(fang)式存在差異(yi)：熔(rong)(rong)融開(kai)始(shi)時(shi)(shi)，隨(sui)(sui)溫(wen)度(du)的(de)(de)(de)升高，熔(rong)(rong)點(dian)較低(di)的(de)(de)(de)雜質(zhi)(zhi)(zhi)先達到熔(rong)(rong)點(dian)溫(wen)度(du)，并(bing)轉變(bian)成液態;隨(sui)(sui)溫(wen)度(du)繼續(xu)升高，當達到氧(yang)(yang)化鎂(mei)(mei)(mei)熔(rong)(rong)點(dian)溫(wen)度(du)時(shi)(shi)，此(ci)時(shi)(shi)氧(yang)(yang)化鎂(mei)(mei)(mei)開(kai)始(shi)熔(rong)(rong)化，因氧(yang)(yang)化鎂(mei)(mei)(mei)的(de)(de)(de)密度(du)相(xiang)對(dui)較高，其它雜質(zhi)(zhi)(zhi)的(de)(de)(de)密度(du)相(xiang)對(dui)較低(di)，加上(shang)熔(rong)(rong)池中二(er)氧(yang)(yang)化碳(tan)和水(shui)蒸(zheng)氣的(de)(de)(de)不(bu)斷上(shang)升，使得雜質(zhi)(zhi)(zhi)逐漸(jian)向上(shang)遷移。

      總(zong)之，目(mu)前電熔(rong)鎂砂傳統生(sheng)(sheng)產(chan)(chan)工藝是以(yi)菱鎂礦(kuang)為原料，通過電弧(hu)爐高溫熔(rong)煉制(zhi)(zhi)備(bei)而成，但該(gai)法存在產(chan)(chan)品質量不高、生(sheng)(sheng)產(chan)(chan)能(neng)耗(hao)高、環境污染嚴重、工作強度(du)大等缺陷。而利用鹽湖(hu)鹵水制(zhi)(zhi)備(bei)的(de)(de)高純(chun)Mg(OH)2中(zhong)間體為原料生(sheng)(sheng)產(chan)(chan)高純(chun)電熔(rong)鎂砂，具有產(chan)(chan)品附加(jia)值高、生(sheng)(sheng)產(chan)(chan)處理量大、能(neng)耗(hao)低(di)等優異特點，解決了國內外高端鎂砂制(zhi)(zhi)品的(de)(de)需求。因此，該(gai)工藝是今(jin)后高純(chun)電熔(rong)鎂砂制(zhi)(zhi)備(bei)的(de)(de)主(zhu)流方向。

電熔鎂砂