萬州電熔鎂砂是重要的工(gong)(gong)(gong)業原材料(liao)，其生(sheng)產工(gong)(gong)(gong)藝簡單，主要以(yi)氧(yang)化鎂(mei)壓球料(liao)為原料(liao)，采用電弧(hu)爐熔融(rong)法制(zhi)備而(er)成。我國電熔鎂(mei)砂制(zhi)備工(gong)(gong)(gong)藝技術方面的研究成果(guo)，主要表現在選擇(ze)適宜的化學添加劑改善(shan)鎂(mei)砂的性能(neng)以(yi)及高效新工(gong)(gong)(gong)藝的開(kai)發(fa)。

我國電熔(rong)鎂(mei)砂制備工藝及(ji)應用

      我國電(dian)(dian)熔(rong)鎂(mei)(mei)砂制(zhi)備優(you)化工藝。當(dang)前我國電(dian)(dian)熔(rong)鎂(mei)(mei)產業仍在沿用(yong)電(dian)(dian)弧爐生(sheng)產方(fang)式(shi)，技(ji)術裝(zhuang)(zhuang)備相對(dui)落后，效率低，能(neng)(neng)源(yuan)浪費(fei)嚴(yan)重，余熱(re)潛能(neng)(neng)流(liu)失嚴(yan)重;電(dian)(dian)熔(rong)鎂(mei)(mei)砂生(sheng)產過程中還存在著嚴(yan)重的(de)粉(fen)塵(chen)污染，并大(da)(da)量(liang)排(pai)放二氧化碳，加重了大(da)(da)氣溫室效應，惡化周邊環境(jing)。現有電(dian)(dian)熔(rong)鎂(mei)(mei)技(ji)術裝(zhuang)(zhuang)備亟待(dai)更新(xin)換代，現有工藝急(ji)需創新(xin)，因(yin)此，采用(yong)集(ji)成技(ji)術發展節能(neng)(neng)環保的(de)新(xin)式(shi)電(dian)(dian)熔(rong)鎂(mei)(mei)裝(zhuang)(zhuang)備及制(zhi)備工藝是發展電(dian)(dian)熔(rong)鎂(mei)(mei)產業的(de)重要選擇。

      近年來(lai)，國(guo)(guo)內的(de)(de)科技工作者在(zai)電熔鎂(mei)(mei)砂(sha)的(de)(de)生(sheng)(sheng)(sheng)產(chan)工藝(yi)方面進行了改進和優化(hua)，并取得了一(yi)定(ding)的(de)(de)成(cheng)效。電熔鎂(mei)(mei)砂(sha)的(de)(de)生(sheng)(sheng)(sheng)產(chan)工藝(yi)流(liu)程短而(er)簡單，但設(she)備(bei)(bei)投(tou)入和資源(yuan)消耗大。我國(guo)(guo)電熔鎂(mei)(mei)砂(sha)產(chan)業多(duo)采用電弧(hu)爐熔融天然菱鎂(mei)(mei)礦石制(zhi)備(bei)(bei)電熔鎂(mei)(mei)砂(sha)，生(sheng)(sheng)(sheng)產(chan)工藝(yi)技術裝備(bei)(bei)落后(hou)，功率(lv)低(di)、容量小、效率(lv)低(di)、自動化(hua)程度(du)低(di)，生(sheng)(sheng)(sheng)產(chan)出的(de)(de)電熔鎂(mei)(mei)砂(sha)產(chan)品品位不高(gao)(gao)，導致鎂(mei)(mei)資源(yuan)利用率(lv)低(di)，環(huan)境(jing)污染嚴重(zhong)。通過利用鹽湖鹵水與(yu)氨氣反應后(hou)生(sheng)(sheng)(sheng)成(cheng)氫氧(yang)(yang)化(hua)鎂(mei)(mei)在(zai)煅燒(shao)后(hou)生(sheng)(sheng)(sheng)成(cheng)輕質氧(yang)(yang)化(hua)鎂(mei)(mei)，可以通過洗滌、過濾等方法(fa)有(you)效地除(chu)去雜質離(li)子，氧(yang)(yang)化(hua)鎂(mei)(mei)的(de)(de)純度(du)高(gao)(gao)達99.9%，在(zai)較(jiao)低(di)溫度(du)下輕燒(shao)得氧(yang)(yang)化(hua)鎂(mei)(mei)粉末，而(er)后(hou)經一(yi)定(ding)壓力壓球，制(zhi)取高(gao)(gao)純電熔鎂(mei)(mei)砂(sha)。

電熔鎂砂熔煉過程研究

      電(dian)(dian)(dian)(dian)熔(rong)鎂砂(sha)熔(rong)煉工(gong)藝原理。電(dian)(dian)(dian)(dian)熔(rong)鎂砂(sha)是采(cai)用電(dian)(dian)(dian)(dian)弧(hu)熔(rong)融法進(jin)行制(zhi)備，其裝(zhuang)備是電(dian)(dian)(dian)(dian)熔(rong)鎂電(dian)(dian)(dian)(dian)弧(hu)爐(礦熱(re)埋(mai)弧(hu)電(dian)(dian)(dian)(dian)爐)，即通過電(dian)(dian)(dian)(dian)極(ji)的埋(mai)弧(hu)電(dian)(dian)(dian)(dian)熱(re)和物料(liao)的電(dian)(dian)(dian)(dian)阻電(dian)(dian)(dian)(dian)熱(re)來熔(rong)煉物料(liao)。其電(dian)(dian)(dian)(dian)耗很大，爐體一般(ban)呈圓形(xing)，三(san)根電(dian)(dian)(dian)(dian)極(ji)布置成三(san)角形(xing)。電(dian)(dian)(dian)(dian)熔(rong)鎂爐在生產(chan)過程中，是以電(dian)(dian)(dian)(dian)弧(hu)電(dian)(dian)(dian)(dian)熱(re)對爐料(liao)加熱(re)使之(zhi)熔(rong)化，形(xing)成熔(rong)池，電(dian)(dian)(dian)(dian)弧(hu)電(dian)(dian)(dian)(dian)熱(re)越(yue)大，物料(liao)熔(rong)化的速度越(yue)快。

      電(dian)(dian)熔(rong)(rong)鎂(mei)(mei)砂(sha)的(de)制備(bei)是以氫(qing)氧(yang)化鎂(mei)(mei)煅燒氧(yang)化鎂(mei)(mei)壓(ya)制成球后(hou)為(wei)原(yuan)料(liao)(liao)，在4000kVA高(gao)溫電(dian)(dian)弧爐(lu)中經冶煉、熔(rong)(rong)化再結(jie)晶后(hou)形成的(de)鎂(mei)(mei)砂(sha)制品，在不同類型的(de)電(dian)(dian)弧爐(lu)中通過電(dian)(dian)弧加熱產生高(gao)溫(≥2800℃)，使鎂(mei)(mei)質原(yuan)料(liao)(liao)在爐(lu)中受(shou)熱、脫水(shui)(釆用(yong)水(shui)氯(lv)鎂(mei)(mei)石)、溶融、析晶、晶體(ti)長(chang)大、冷卻(que)等(deng)一系列(lie)物(wu)理(li)化學(xue)變化過程，形成一種耐高(gao)溫、硬度大、純度高(gao)的(de)電(dian)(dian)熔(rong)(rong)氧(yang)化鎂(mei)(mei)晶體(ti)。

      電(dian)熔鎂砂的(de)(de)熔煉過程主(zhu)要分為(wei)填料階(jie)段(duan)(duan)(duan)、起(qi)弧階(jie)段(duan)(duan)(duan)、熔融(rong)階(jie)段(duan)(duan)(duan)、加料階(jie)段(duan)(duan)(duan)、冷卻階(jie)段(duan)(duan)(duan)以及停爐階(jie)段(duan)(duan)(duan)：填料階(jie)段(duan)(duan)(duan)。在(zai)(zai)電(dian)熔開(kai)始工作之前需往爐內(nei)裝料，應做到(dao)將料壓實壓密，并在(zai)(zai)粉料的(de)(de)最(zui)上層鋪一層工業冶金焦炭，其平(ping)(ping)鋪范圍(wei)在(zai)(zai)三根電(dian)極(ji)所(suo)形成(cheng)的(de)(de)三角形范圍(wei)內(nei)，使(shi)得起(qi)弧后電(dian)路形成(cheng)回路;起(qi)弧階(jie)段(duan)(duan)(duan)。調節(jie)電(dian)極(ji)，開(kai)始進入起(qi)弧階(jie)段(duan)(duan)(duan);熔融(rong)階(jie)段(duan)(duan)(duan)。起(qi)弧后，待電(dian)流趨(qu)于平(ping)(ping)穩后，電(dian)極(ji)周(zhou)圍(wei)的(de)(de)原(yuan)料開(kai)始熔融(rong)，熔池逐漸形成(cheng);加料階(jie)段(duan)(duan)(duan)。

      隨(sui)氧(yang)(yang)(yang)化(hua)鎂(mei)原料不斷消(xiao)耗，熔(rong)(rong)池(chi)液面開(kai)始下降，待熔(rong)(rong)池(chi)穩(wen)定(ding)(ding)后可往電極周圍填(tian)料，進入(ru)加料階段(duan)(duan)(需注(zhu)意不要破(po)壞熔(rong)(rong)池(chi)的穩(wen)定(ding)(ding)性);冷(leng)卻(que)(que)階段(duan)(duan)。熔(rong)(rong)煉完成(cheng)后，電極逐漸被(bei)氧(yang)(yang)(yang)化(hua)消(xiao)耗，電流減小。需通(tong)過(guo)(guo)冷(leng)卻(que)(que)給熔(rong)(rong)池(chi)內的氧(yang)(yang)(yang)化(hua)鎂(mei)晶體創(chuang)造一(yi)個穩(wen)定(ding)(ding)散熱降溫的環境，使其冷(leng)凝結(jie)晶出多晶氧(yang)(yang)(yang)化(hua)鎂(mei)產品(pin);停爐(lu)(lu)階段(duan)(duan)。停爐(lu)(lu)過(guo)(guo)程中，往往采用手動加料，為了減少排氣，電極附近要加入(ru)氧(yang)(yang)(yang)化(hua)鎂(mei)坯砂(sha)(氧(yang)(yang)(yang)化(hua)鎂(mei)輕燒粉不含CO2)，并(bing)多加細粉料，有利于產品(pin)產量及品(pin)質提(ti)高。電熔(rong)(rong)鎂(mei)砂(sha)熔(rong)(rong)融結(jie)晶過(guo)(guo)程。

      電熔(rong)鎂(mei)(mei)砂的(de)熔(rong)融(rong)結晶過程伴隨(sui)著雜(za)質(zhi)(zhi)的(de)遷(qian)移(yi)和(he)析出(chu)，在熔(rong)煉(lian)過程中，由(you)于(yu)各組分(fen)的(de)熔(rong)點(dian)和(he)密度(du)(du)不(bu)(bu)同，其(qi)析出(chu)方式(shi)存在差異：熔(rong)融(rong)開(kai)始(shi)時(shi)，隨(sui)溫度(du)(du)的(de)升(sheng)(sheng)高(gao)(gao)，熔(rong)點(dian)較低的(de)雜(za)質(zhi)(zhi)先達(da)到熔(rong)點(dian)溫度(du)(du)，并轉變成液態;隨(sui)溫度(du)(du)繼續升(sheng)(sheng)高(gao)(gao)，當達(da)到氧(yang)(yang)化(hua)鎂(mei)(mei)熔(rong)點(dian)溫度(du)(du)時(shi)，此時(shi)氧(yang)(yang)化(hua)鎂(mei)(mei)開(kai)始(shi)熔(rong)化(hua)，因氧(yang)(yang)化(hua)鎂(mei)(mei)的(de)密度(du)(du)相對較高(gao)(gao)，其(qi)它(ta)雜(za)質(zhi)(zhi)的(de)密度(du)(du)相對較低，加上(shang)熔(rong)池中二(er)氧(yang)(yang)化(hua)碳(tan)和(he)水(shui)蒸(zheng)氣的(de)不(bu)(bu)斷(duan)上(shang)升(sheng)(sheng)，使(shi)得雜(za)質(zhi)(zhi)逐(zhu)漸向上(shang)遷(qian)移(yi)。

      總之，目(mu)前電(dian)熔(rong)鎂(mei)砂(sha)傳統生產(chan)工藝是以菱(ling)鎂(mei)礦(kuang)為(wei)原料，通過電(dian)弧(hu)爐(lu)高(gao)(gao)溫熔(rong)煉制備(bei)而成，但該法存在產(chan)品質(zhi)量(liang)不(bu)高(gao)(gao)、生產(chan)能耗高(gao)(gao)、環境污(wu)染嚴重、工作強度大(da)等(deng)缺陷。而利用鹽湖鹵水制備(bei)的(de)高(gao)(gao)純(chun)Mg(OH)2中間體為(wei)原料生產(chan)高(gao)(gao)純(chun)電(dian)熔(rong)鎂(mei)砂(sha)，具(ju)有產(chan)品附加值高(gao)(gao)、生產(chan)處(chu)理量(liang)大(da)、能耗低等(deng)優異特點，解決了國內外高(gao)(gao)端鎂(mei)砂(sha)制品的(de)需(xu)求。因此，該工藝是今后高(gao)(gao)純(chun)電(dian)熔(rong)鎂(mei)砂(sha)制備(bei)的(de)主流方向。

電熔鎂砂