五指山電熔鎂砂是重要(yao)(yao)的工(gong)業原材料，其生(sheng)產工(gong)藝簡單，主要(yao)(yao)以(yi)氧化鎂(mei)(mei)壓球料為(wei)原料，采用(yong)電弧爐熔(rong)融法制備而(er)成(cheng)。我國電熔(rong)鎂(mei)(mei)砂制備工(gong)藝技術方面的研究成(cheng)果，主要(yao)(yao)表現在選擇適宜的化學(xue)添加劑改善鎂(mei)(mei)砂的性能以(yi)及高(gao)效(xiao)新工(gong)藝的開發(fa)。

我國(guo)電熔(rong)鎂砂制備工藝(yi)及應(ying)用

      我國(guo)(guo)電熔(rong)鎂(mei)(mei)砂制備(bei)優化工藝。當前我國(guo)(guo)電熔(rong)鎂(mei)(mei)產(chan)業仍在沿用電弧爐生產(chan)方式(shi)，技術裝備(bei)相對落(luo)后，效(xiao)率低，能(neng)源浪費嚴(yan)重(zhong)，余熱潛能(neng)流(liu)失嚴(yan)重(zhong);電熔(rong)鎂(mei)(mei)砂生產(chan)過(guo)程中(zhong)還存在著嚴(yan)重(zhong)的粉塵污染，并大量排放二氧化碳(tan)，加重(zhong)了大氣溫室效(xiao)應，惡(e)化周邊(bian)環境。現(xian)有(you)電熔(rong)鎂(mei)(mei)技術裝備(bei)亟(ji)待更(geng)新換代，現(xian)有(you)工藝急需創(chuang)新，因此，采用集成(cheng)技術發展節能(neng)環保的新式(shi)電熔(rong)鎂(mei)(mei)裝備(bei)及制備(bei)工藝是發展電熔(rong)鎂(mei)(mei)產(chan)業的重(zhong)要(yao)選擇。

      近年來，國內的(de)科(ke)技工(gong)(gong)作(zuo)者在電熔(rong)(rong)鎂(mei)(mei)(mei)(mei)砂(sha)(sha)的(de)生(sheng)產工(gong)(gong)藝方(fang)(fang)面進行了(le)改進和優化(hua)(hua)，并(bing)取得(de)了(le)一定的(de)成效(xiao)。電熔(rong)(rong)鎂(mei)(mei)(mei)(mei)砂(sha)(sha)的(de)生(sheng)產工(gong)(gong)藝流程(cheng)短(duan)而簡(jian)單，但設備投入和資源消耗大。我國電熔(rong)(rong)鎂(mei)(mei)(mei)(mei)砂(sha)(sha)產業多采(cai)用電弧爐熔(rong)(rong)融(rong)天然(ran)菱鎂(mei)(mei)(mei)(mei)礦石制備電熔(rong)(rong)鎂(mei)(mei)(mei)(mei)砂(sha)(sha)，生(sheng)產工(gong)(gong)藝技術(shu)裝備落后(hou)，功率低(di)(di)、容量小、效(xiao)率低(di)(di)、自動化(hua)(hua)程(cheng)度低(di)(di)，生(sheng)產出的(de)電熔(rong)(rong)鎂(mei)(mei)(mei)(mei)砂(sha)(sha)產品(pin)品(pin)位不高，導致鎂(mei)(mei)(mei)(mei)資源利用率低(di)(di)，環(huan)境污染(ran)嚴重。通(tong)過(guo)利用鹽湖鹵水(shui)與氨氣反應(ying)后(hou)生(sheng)成氫氧(yang)化(hua)(hua)鎂(mei)(mei)(mei)(mei)在煅燒后(hou)生(sheng)成輕質氧(yang)化(hua)(hua)鎂(mei)(mei)(mei)(mei)，可以通(tong)過(guo)洗(xi)滌、過(guo)濾(lv)等方(fang)(fang)法有效(xiao)地除去雜質離子，氧(yang)化(hua)(hua)鎂(mei)(mei)(mei)(mei)的(de)純度高達99.9%，在較低(di)(di)溫度下輕燒得(de)氧(yang)化(hua)(hua)鎂(mei)(mei)(mei)(mei)粉末，而后(hou)經一定壓(ya)力(li)壓(ya)球，制取高純電熔(rong)(rong)鎂(mei)(mei)(mei)(mei)砂(sha)(sha)。

電熔(rong)鎂砂熔(rong)煉過程(cheng)研究

      電(dian)(dian)(dian)(dian)(dian)熔(rong)(rong)(rong)鎂砂熔(rong)(rong)(rong)煉(lian)工藝原理。電(dian)(dian)(dian)(dian)(dian)熔(rong)(rong)(rong)鎂砂是(shi)采用電(dian)(dian)(dian)(dian)(dian)弧(hu)熔(rong)(rong)(rong)融法進行制備，其(qi)裝備是(shi)電(dian)(dian)(dian)(dian)(dian)熔(rong)(rong)(rong)鎂電(dian)(dian)(dian)(dian)(dian)弧(hu)爐(lu)(礦熱(re)埋(mai)弧(hu)電(dian)(dian)(dian)(dian)(dian)爐(lu))，即通過(guo)電(dian)(dian)(dian)(dian)(dian)極(ji)的(de)埋(mai)弧(hu)電(dian)(dian)(dian)(dian)(dian)熱(re)和物料(liao)(liao)的(de)電(dian)(dian)(dian)(dian)(dian)阻電(dian)(dian)(dian)(dian)(dian)熱(re)來熔(rong)(rong)(rong)煉(lian)物料(liao)(liao)。其(qi)電(dian)(dian)(dian)(dian)(dian)耗很(hen)大，爐(lu)體(ti)一般呈(cheng)圓形，三根電(dian)(dian)(dian)(dian)(dian)極(ji)布(bu)置成(cheng)三角形。電(dian)(dian)(dian)(dian)(dian)熔(rong)(rong)(rong)鎂爐(lu)在生產(chan)過(guo)程中(zhong)，是(shi)以電(dian)(dian)(dian)(dian)(dian)弧(hu)電(dian)(dian)(dian)(dian)(dian)熱(re)對爐(lu)料(liao)(liao)加熱(re)使之熔(rong)(rong)(rong)化，形成(cheng)熔(rong)(rong)(rong)池，電(dian)(dian)(dian)(dian)(dian)弧(hu)電(dian)(dian)(dian)(dian)(dian)熱(re)越大，物料(liao)(liao)熔(rong)(rong)(rong)化的(de)速度越快。

      電熔鎂(mei)(mei)砂(sha)的制(zhi)備是(shi)以氫氧(yang)化(hua)鎂(mei)(mei)煅燒氧(yang)化(hua)鎂(mei)(mei)壓制(zhi)成球后(hou)為原料(liao)，在4000kVA高(gao)溫電弧(hu)爐中經冶煉、熔化(hua)再結晶后(hou)形成的鎂(mei)(mei)砂(sha)制(zhi)品，在不同類型的電弧(hu)爐中通過電弧(hu)加(jia)熱(re)產生高(gao)溫(≥2800℃)，使鎂(mei)(mei)質原料(liao)在爐中受熱(re)、脫水(釆用(yong)水氯鎂(mei)(mei)石)、溶融、析晶、晶體長大(da)(da)、冷卻等一系列物理化(hua)學變化(hua)過程(cheng)，形成一種耐高(gao)溫、硬度大(da)(da)、純度高(gao)的電熔氧(yang)化(hua)鎂(mei)(mei)晶體。

      電(dian)(dian)(dian)熔(rong)鎂砂的(de)熔(rong)煉過程(cheng)主(zhu)要分為填料(liao)(liao)階(jie)(jie)段(duan)、起(qi)弧(hu)(hu)(hu)階(jie)(jie)段(duan)、熔(rong)融階(jie)(jie)段(duan)、加料(liao)(liao)階(jie)(jie)段(duan)、冷卻階(jie)(jie)段(duan)以及停爐階(jie)(jie)段(duan)：填料(liao)(liao)階(jie)(jie)段(duan)。在(zai)電(dian)(dian)(dian)熔(rong)開始(shi)工(gong)(gong)作之前需(xu)往爐內(nei)裝料(liao)(liao)，應做到將料(liao)(liao)壓實壓密，并在(zai)粉料(liao)(liao)的(de)最上(shang)層鋪(pu)一層工(gong)(gong)業冶(ye)金焦炭(tan)，其平(ping)鋪(pu)范圍在(zai)三根電(dian)(dian)(dian)極所(suo)形成(cheng)的(de)三角形范圍內(nei)，使得起(qi)弧(hu)(hu)(hu)后(hou)電(dian)(dian)(dian)路形成(cheng)回路;起(qi)弧(hu)(hu)(hu)階(jie)(jie)段(duan)。調節電(dian)(dian)(dian)極，開始(shi)進入(ru)起(qi)弧(hu)(hu)(hu)階(jie)(jie)段(duan);熔(rong)融階(jie)(jie)段(duan)。起(qi)弧(hu)(hu)(hu)后(hou)，待電(dian)(dian)(dian)流趨(qu)于(yu)平(ping)穩后(hou)，電(dian)(dian)(dian)極周圍的(de)原(yuan)料(liao)(liao)開始(shi)熔(rong)融，熔(rong)池逐漸形成(cheng);加料(liao)(liao)階(jie)(jie)段(duan)。

      隨氧(yang)(yang)化鎂(mei)(mei)原料(liao)不(bu)斷(duan)消(xiao)耗(hao)(hao)，熔(rong)(rong)池(chi)液(ye)面開始(shi)下降，待熔(rong)(rong)池(chi)穩定后可往(wang)電極周(zhou)圍填料(liao)，進入加(jia)料(liao)階段(需(xu)注意不(bu)要破壞熔(rong)(rong)池(chi)的(de)穩定性(xing));冷(leng)卻階段。熔(rong)(rong)煉完(wan)成后，電極逐(zhu)漸被氧(yang)(yang)化消(xiao)耗(hao)(hao)，電流減(jian)小(xiao)。需(xu)通過冷(leng)卻給熔(rong)(rong)池(chi)內的(de)氧(yang)(yang)化鎂(mei)(mei)晶(jing)體(ti)創造一個穩定散熱降溫的(de)環境(jing)，使其冷(leng)凝結晶(jing)出多晶(jing)氧(yang)(yang)化鎂(mei)(mei)產品;停爐(lu)階段。停爐(lu)過程(cheng)中，往(wang)往(wang)采用(yong)手(shou)動加(jia)料(liao)，為了減(jian)少排(pai)氣，電極附近要加(jia)入氧(yang)(yang)化鎂(mei)(mei)坯砂(氧(yang)(yang)化鎂(mei)(mei)輕燒粉不(bu)含CO2)，并多加(jia)細粉料(liao)，有利于產品產量及品質(zhi)提高。電熔(rong)(rong)鎂(mei)(mei)砂熔(rong)(rong)融(rong)結晶(jing)過程(cheng)。

      電(dian)熔(rong)鎂(mei)(mei)(mei)砂(sha)的(de)熔(rong)融結晶過程(cheng)伴隨著雜質的(de)遷(qian)移和析(xi)出，在熔(rong)煉過程(cheng)中，由于各組分的(de)熔(rong)點(dian)和密度不同，其(qi)析(xi)出方式存在差異：熔(rong)融開(kai)(kai)始時，隨溫(wen)度的(de)升(sheng)高，熔(rong)點(dian)較(jiao)低的(de)雜質先達到熔(rong)點(dian)溫(wen)度，并轉(zhuan)變成液態;隨溫(wen)度繼續升(sheng)高，當(dang)達到氧(yang)化(hua)鎂(mei)(mei)(mei)熔(rong)點(dian)溫(wen)度時，此時氧(yang)化(hua)鎂(mei)(mei)(mei)開(kai)(kai)始熔(rong)化(hua)，因(yin)氧(yang)化(hua)鎂(mei)(mei)(mei)的(de)密度相對較(jiao)高，其(qi)它雜質的(de)密度相對較(jiao)低，加(jia)上熔(rong)池中二氧(yang)化(hua)碳和水蒸氣的(de)不斷上升(sheng)，使得雜質逐漸向上遷(qian)移。

      總(zong)之，目前電(dian)熔鎂(mei)砂傳統生產工藝是以菱鎂(mei)礦(kuang)為(wei)原(yuan)料，通過電(dian)弧爐(lu)高(gao)(gao)(gao)(gao)溫熔煉(lian)制備(bei)而(er)成，但該法存在產品質量(liang)不(bu)高(gao)(gao)(gao)(gao)、生產能(neng)耗高(gao)(gao)(gao)(gao)、環(huan)境污染嚴重、工作(zuo)強度大(da)等缺(que)陷。而(er)利用鹽湖鹵水制備(bei)的(de)高(gao)(gao)(gao)(gao)純(chun)Mg(OH)2中間體為(wei)原(yuan)料生產高(gao)(gao)(gao)(gao)純(chun)電(dian)熔鎂(mei)砂，具有產品附加值高(gao)(gao)(gao)(gao)、生產處理量(liang)大(da)、能(neng)耗低等優異特(te)點，解決了國內外(wai)高(gao)(gao)(gao)(gao)端鎂(mei)砂制品的(de)需求(qiu)。因(yin)此，該工藝是今(jin)后高(gao)(gao)(gao)(gao)純(chun)電(dian)熔鎂(mei)砂制備(bei)的(de)主流方(fang)向。

電熔鎂砂