濰坊電熔鎂砂是重(zhong)要(yao)的(de)工(gong)(gong)業原材料，其生產工(gong)(gong)藝(yi)簡單，主要(yao)以氧化(hua)鎂壓(ya)球(qiu)料為原料，采用電弧爐熔(rong)融法制備(bei)而成(cheng)。我國電熔(rong)鎂砂制備(bei)工(gong)(gong)藝(yi)技術方面的(de)研究(jiu)成(cheng)果(guo)，主要(yao)表現在選(xuan)擇適宜的(de)化(hua)學(xue)添加劑改善鎂砂的(de)性能以及高效(xiao)新(xin)工(gong)(gong)藝(yi)的(de)開發。

我(wo)國電(dian)熔(rong)鎂(mei)砂制(zhi)備工(gong)藝及應(ying)用

      我國(guo)電(dian)(dian)熔(rong)鎂(mei)(mei)砂制備(bei)(bei)優化工(gong)藝。當前(qian)我國(guo)電(dian)(dian)熔(rong)鎂(mei)(mei)產業(ye)仍在沿用電(dian)(dian)弧爐生(sheng)產方式，技術裝(zhuang)備(bei)(bei)相對落后，效率低，能源(yuan)浪費嚴重(zhong)，余熱潛(qian)能流失嚴重(zhong);電(dian)(dian)熔(rong)鎂(mei)(mei)砂生(sheng)產過程中還(huan)存(cun)在著嚴重(zhong)的(de)粉(fen)塵污染，并大量排放二氧化碳，加重(zhong)了(le)大氣溫室(shi)效應，惡化周邊(bian)環境。現有電(dian)(dian)熔(rong)鎂(mei)(mei)技術裝(zhuang)備(bei)(bei)亟待更新換代，現有工(gong)藝急需(xu)創(chuang)新，因此，采用集(ji)成技術發展(zhan)節能環保的(de)新式電(dian)(dian)熔(rong)鎂(mei)(mei)裝(zhuang)備(bei)(bei)及制備(bei)(bei)工(gong)藝是發展(zhan)電(dian)(dian)熔(rong)鎂(mei)(mei)產業(ye)的(de)重(zhong)要選擇。

      近(jin)年來(lai)，國內的(de)(de)科技工作(zuo)者在電(dian)(dian)(dian)熔(rong)(rong)鎂(mei)(mei)(mei)砂的(de)(de)生(sheng)產(chan)工藝(yi)方面進(jin)行了改(gai)進(jin)和優化(hua)，并取得了一(yi)定的(de)(de)成效(xiao)。電(dian)(dian)(dian)熔(rong)(rong)鎂(mei)(mei)(mei)砂的(de)(de)生(sheng)產(chan)工藝(yi)流程(cheng)短而簡單，但設備(bei)投入和資(zi)源(yuan)消耗大。我(wo)國電(dian)(dian)(dian)熔(rong)(rong)鎂(mei)(mei)(mei)砂產(chan)業多(duo)采用電(dian)(dian)(dian)弧爐熔(rong)(rong)融天然(ran)菱鎂(mei)(mei)(mei)礦石制備(bei)電(dian)(dian)(dian)熔(rong)(rong)鎂(mei)(mei)(mei)砂，生(sheng)產(chan)工藝(yi)技術裝備(bei)落后，功率低(di)(di)、容量小、效(xiao)率低(di)(di)、自動化(hua)程(cheng)度(du)(du)低(di)(di)，生(sheng)產(chan)出(chu)的(de)(de)電(dian)(dian)(dian)熔(rong)(rong)鎂(mei)(mei)(mei)砂產(chan)品(pin)品(pin)位不(bu)高，導致鎂(mei)(mei)(mei)資(zi)源(yuan)利用率低(di)(di)，環境污染嚴重。通(tong)過利用鹽(yan)湖鹵水與氨氣反應(ying)后生(sheng)成氫氧化(hua)鎂(mei)(mei)(mei)在煅燒后生(sheng)成輕(qing)(qing)質氧化(hua)鎂(mei)(mei)(mei)，可(ke)以通(tong)過洗(xi)滌、過濾(lv)等方法有效(xiao)地(di)除(chu)去雜質離子，氧化(hua)鎂(mei)(mei)(mei)的(de)(de)純(chun)度(du)(du)高達99.9%，在較低(di)(di)溫度(du)(du)下輕(qing)(qing)燒得氧化(hua)鎂(mei)(mei)(mei)粉末，而后經一(yi)定壓力壓球，制取高純(chun)電(dian)(dian)(dian)熔(rong)(rong)鎂(mei)(mei)(mei)砂。

電熔鎂砂熔煉過(guo)程研究(jiu)

      電(dian)(dian)(dian)(dian)(dian)熔(rong)(rong)鎂(mei)砂熔(rong)(rong)煉工(gong)藝原理。電(dian)(dian)(dian)(dian)(dian)熔(rong)(rong)鎂(mei)砂是(shi)(shi)(shi)采用電(dian)(dian)(dian)(dian)(dian)弧(hu)(hu)熔(rong)(rong)融法進行制(zhi)備，其裝備是(shi)(shi)(shi)電(dian)(dian)(dian)(dian)(dian)熔(rong)(rong)鎂(mei)電(dian)(dian)(dian)(dian)(dian)弧(hu)(hu)爐(lu)(礦熱(re)(re)埋弧(hu)(hu)電(dian)(dian)(dian)(dian)(dian)爐(lu))，即通過電(dian)(dian)(dian)(dian)(dian)極的埋弧(hu)(hu)電(dian)(dian)(dian)(dian)(dian)熱(re)(re)和(he)物(wu)(wu)料(liao)(liao)(liao)的電(dian)(dian)(dian)(dian)(dian)阻電(dian)(dian)(dian)(dian)(dian)熱(re)(re)來熔(rong)(rong)煉物(wu)(wu)料(liao)(liao)(liao)。其電(dian)(dian)(dian)(dian)(dian)耗很(hen)大，爐(lu)體一般(ban)呈圓形(xing)，三根電(dian)(dian)(dian)(dian)(dian)極布置成三角形(xing)。電(dian)(dian)(dian)(dian)(dian)熔(rong)(rong)鎂(mei)爐(lu)在(zai)生產過程(cheng)中，是(shi)(shi)(shi)以電(dian)(dian)(dian)(dian)(dian)弧(hu)(hu)電(dian)(dian)(dian)(dian)(dian)熱(re)(re)對爐(lu)料(liao)(liao)(liao)加(jia)熱(re)(re)使之熔(rong)(rong)化，形(xing)成熔(rong)(rong)池，電(dian)(dian)(dian)(dian)(dian)弧(hu)(hu)電(dian)(dian)(dian)(dian)(dian)熱(re)(re)越(yue)(yue)大，物(wu)(wu)料(liao)(liao)(liao)熔(rong)(rong)化的速(su)度越(yue)(yue)快。

      電熔(rong)鎂(mei)(mei)砂的(de)(de)制備是以氫(qing)氧化鎂(mei)(mei)煅燒(shao)氧化鎂(mei)(mei)壓制成球后為原料，在(zai)(zai)4000kVA高溫電弧(hu)爐中(zhong)經冶煉、熔(rong)化再結晶后形成的(de)(de)鎂(mei)(mei)砂制品，在(zai)(zai)不同類型的(de)(de)電弧(hu)爐中(zhong)通(tong)過電弧(hu)加熱(re)產生高溫(≥2800℃)，使鎂(mei)(mei)質原料在(zai)(zai)爐中(zhong)受(shou)熱(re)、脫水(釆用水氯鎂(mei)(mei)石)、溶(rong)融、析(xi)晶、晶體長大(da)、冷卻(que)等(deng)一(yi)系(xi)列物理化學(xue)變化過程，形成一(yi)種耐(nai)高溫、硬度大(da)、純度高的(de)(de)電熔(rong)氧化鎂(mei)(mei)晶體。

      電(dian)(dian)熔(rong)(rong)(rong)鎂砂的熔(rong)(rong)(rong)煉過程主(zhu)要分為填料階(jie)(jie)段(duan)(duan)、起(qi)(qi)弧(hu)階(jie)(jie)段(duan)(duan)、熔(rong)(rong)(rong)融(rong)階(jie)(jie)段(duan)(duan)、加(jia)料階(jie)(jie)段(duan)(duan)、冷卻階(jie)(jie)段(duan)(duan)以及停爐階(jie)(jie)段(duan)(duan)：填料階(jie)(jie)段(duan)(duan)。在電(dian)(dian)熔(rong)(rong)(rong)開(kai)(kai)始(shi)工作(zuo)之前(qian)需(xu)往爐內裝料，應做(zuo)到將料壓實壓密，并在粉料的最(zui)上層鋪(pu)一層工業冶金焦炭，其平(ping)鋪(pu)范圍(wei)在三根(gen)電(dian)(dian)極所(suo)形成的三角形范圍(wei)內，使(shi)得(de)起(qi)(qi)弧(hu)后電(dian)(dian)路(lu)形成回路(lu);起(qi)(qi)弧(hu)階(jie)(jie)段(duan)(duan)。調節(jie)電(dian)(dian)極，開(kai)(kai)始(shi)進入起(qi)(qi)弧(hu)階(jie)(jie)段(duan)(duan);熔(rong)(rong)(rong)融(rong)階(jie)(jie)段(duan)(duan)。起(qi)(qi)弧(hu)后，待(dai)電(dian)(dian)流(liu)趨(qu)于平(ping)穩后，電(dian)(dian)極周圍(wei)的原(yuan)料開(kai)(kai)始(shi)熔(rong)(rong)(rong)融(rong)，熔(rong)(rong)(rong)池(chi)逐(zhu)漸形成;加(jia)料階(jie)(jie)段(duan)(duan)。

      隨(sui)氧(yang)化鎂(mei)原料(liao)不(bu)斷消耗，熔(rong)(rong)池(chi)液面開始下降，待熔(rong)(rong)池(chi)穩定后可往電(dian)極周圍填料(liao)，進入加料(liao)階(jie)段(需(xu)注(zhu)意不(bu)要(yao)破壞熔(rong)(rong)池(chi)的穩定性);冷卻(que)階(jie)段。熔(rong)(rong)煉完成后，電(dian)極逐漸被(bei)氧(yang)化消耗，電(dian)流減小。需(xu)通(tong)過冷卻(que)給熔(rong)(rong)池(chi)內的氧(yang)化鎂(mei)晶(jing)體創(chuang)造一個(ge)穩定散(san)熱(re)降溫的環境，使其冷凝結晶(jing)出多(duo)晶(jing)氧(yang)化鎂(mei)產(chan)品;停爐階(jie)段。停爐過程(cheng)中，往往采用(yong)手動加料(liao)，為了減少(shao)排(pai)氣(qi)，電(dian)極附近要(yao)加入氧(yang)化鎂(mei)坯(pi)砂(氧(yang)化鎂(mei)輕燒(shao)粉(fen)不(bu)含CO2)，并多(duo)加細粉(fen)料(liao)，有利于產(chan)品產(chan)量及品質提(ti)高。電(dian)熔(rong)(rong)鎂(mei)砂熔(rong)(rong)融結晶(jing)過程(cheng)。

      電熔(rong)(rong)(rong)鎂(mei)砂的(de)(de)(de)熔(rong)(rong)(rong)融(rong)結晶過(guo)程伴隨(sui)著雜質的(de)(de)(de)遷移和析出(chu)，在熔(rong)(rong)(rong)煉過(guo)程中，由于(yu)各組分(fen)的(de)(de)(de)熔(rong)(rong)(rong)點(dian)和密度不(bu)(bu)同(tong)，其析出(chu)方式存在差異：熔(rong)(rong)(rong)融(rong)開始時(shi)，隨(sui)溫度的(de)(de)(de)升(sheng)高，熔(rong)(rong)(rong)點(dian)較(jiao)低的(de)(de)(de)雜質先達到(dao)(dao)熔(rong)(rong)(rong)點(dian)溫度，并轉變成液態(tai);隨(sui)溫度繼(ji)續升(sheng)高，當達到(dao)(dao)氧(yang)化(hua)鎂(mei)熔(rong)(rong)(rong)點(dian)溫度時(shi)，此時(shi)氧(yang)化(hua)鎂(mei)開始熔(rong)(rong)(rong)化(hua)，因氧(yang)化(hua)鎂(mei)的(de)(de)(de)密度相對較(jiao)高，其它(ta)雜質的(de)(de)(de)密度相對較(jiao)低，加(jia)上(shang)熔(rong)(rong)(rong)池中二(er)氧(yang)化(hua)碳和水蒸氣的(de)(de)(de)不(bu)(bu)斷上(shang)升(sheng)，使得雜質逐漸向上(shang)遷移。

      總之，目前電熔(rong)鎂(mei)砂(sha)傳(chuan)統生(sheng)產工(gong)(gong)藝是(shi)以菱鎂(mei)礦為(wei)原料，通過電弧爐高(gao)(gao)(gao)溫熔(rong)煉制(zhi)(zhi)備而(er)(er)成(cheng)，但該法存(cun)在產品質量不高(gao)(gao)(gao)、生(sheng)產能耗高(gao)(gao)(gao)、環境(jing)污染嚴(yan)重、工(gong)(gong)作強度大(da)等缺陷。而(er)(er)利(li)用(yong)鹽湖鹵水制(zhi)(zhi)備的(de)高(gao)(gao)(gao)純(chun)(chun)Mg(OH)2中間體為(wei)原料生(sheng)產高(gao)(gao)(gao)純(chun)(chun)電熔(rong)鎂(mei)砂(sha)，具有產品附加值(zhi)高(gao)(gao)(gao)、生(sheng)產處理量大(da)、能耗低等優異特點，解(jie)決了國內外高(gao)(gao)(gao)端鎂(mei)砂(sha)制(zhi)(zhi)品的(de)需求。因此，該工(gong)(gong)藝是(shi)今后高(gao)(gao)(gao)純(chun)(chun)電熔(rong)鎂(mei)砂(sha)制(zhi)(zhi)備的(de)主流方向。

電熔鎂砂