溫州電熔鎂砂是重要的工(gong)業原(yuan)材料(liao)，其生產工(gong)藝簡(jian)單，主(zhu)要以氧(yang)化鎂壓球料(liao)為(wei)原(yuan)料(liao)，采用(yong)電(dian)(dian)弧爐熔(rong)融法(fa)制(zhi)備(bei)而成(cheng)。我國電(dian)(dian)熔(rong)鎂砂制(zhi)備(bei)工(gong)藝技術方面的研究成(cheng)果，主(zhu)要表(biao)現在選擇適宜的化學添(tian)加劑改善鎂砂的性能以及高(gao)效新工(gong)藝的開發。

我(wo)國電熔鎂砂制備工(gong)藝(yi)及應用

      我國電熔(rong)(rong)鎂(mei)(mei)砂(sha)(sha)制備優化工(gong)藝。當前(qian)我國電熔(rong)(rong)鎂(mei)(mei)產(chan)(chan)業(ye)仍在沿用電弧(hu)爐生產(chan)(chan)方式，技術裝(zhuang)(zhuang)備相對落后，效(xiao)率低，能源浪費嚴重(zhong)(zhong)(zhong)，余熱潛(qian)能流失嚴重(zhong)(zhong)(zhong);電熔(rong)(rong)鎂(mei)(mei)砂(sha)(sha)生產(chan)(chan)過程中還存在著嚴重(zhong)(zhong)(zhong)的粉塵污染，并(bing)大量排放二(er)氧(yang)化碳，加重(zhong)(zhong)(zhong)了大氣溫室效(xiao)應，惡化周邊環(huan)境。現(xian)有電熔(rong)(rong)鎂(mei)(mei)技術裝(zhuang)(zhuang)備亟待更(geng)新(xin)換(huan)代，現(xian)有工(gong)藝急需創(chuang)新(xin)，因此，采用集(ji)成(cheng)技術發展節(jie)能環(huan)保的新(xin)式電熔(rong)(rong)鎂(mei)(mei)裝(zhuang)(zhuang)備及制備工(gong)藝是(shi)發展電熔(rong)(rong)鎂(mei)(mei)產(chan)(chan)業(ye)的重(zhong)(zhong)(zhong)要選擇。

      近年來，國內的科技(ji)(ji)工(gong)作者(zhe)在(zai)電(dian)(dian)熔(rong)(rong)(rong)鎂(mei)(mei)(mei)(mei)砂的生(sheng)(sheng)產(chan)(chan)(chan)(chan)工(gong)藝(yi)方面進(jin)行了改進(jin)和(he)(he)優(you)化(hua)(hua)(hua)，并(bing)取(qu)得了一定的成(cheng)效。電(dian)(dian)熔(rong)(rong)(rong)鎂(mei)(mei)(mei)(mei)砂的生(sheng)(sheng)產(chan)(chan)(chan)(chan)工(gong)藝(yi)流程短而簡單(dan)，但設(she)備(bei)投(tou)入和(he)(he)資(zi)源(yuan)(yuan)消耗大。我國電(dian)(dian)熔(rong)(rong)(rong)鎂(mei)(mei)(mei)(mei)砂產(chan)(chan)(chan)(chan)業(ye)多采用(yong)電(dian)(dian)弧爐(lu)熔(rong)(rong)(rong)融天然菱鎂(mei)(mei)(mei)(mei)礦石制(zhi)(zhi)備(bei)電(dian)(dian)熔(rong)(rong)(rong)鎂(mei)(mei)(mei)(mei)砂，生(sheng)(sheng)產(chan)(chan)(chan)(chan)工(gong)藝(yi)技(ji)(ji)術裝備(bei)落后，功率(lv)低、容(rong)量小、效率(lv)低、自動化(hua)(hua)(hua)程度(du)低，生(sheng)(sheng)產(chan)(chan)(chan)(chan)出的電(dian)(dian)熔(rong)(rong)(rong)鎂(mei)(mei)(mei)(mei)砂產(chan)(chan)(chan)(chan)品品位不(bu)高，導致鎂(mei)(mei)(mei)(mei)資(zi)源(yuan)(yuan)利(li)用(yong)率(lv)低，環境污染嚴重。通過(guo)利(li)用(yong)鹽湖(hu)鹵水與氨氣反應后生(sheng)(sheng)成(cheng)氫氧(yang)化(hua)(hua)(hua)鎂(mei)(mei)(mei)(mei)在(zai)煅燒(shao)后生(sheng)(sheng)成(cheng)輕(qing)質氧(yang)化(hua)(hua)(hua)鎂(mei)(mei)(mei)(mei)，可(ke)以(yi)通過(guo)洗滌(di)、過(guo)濾(lv)等方法有(you)效地除去雜質離子，氧(yang)化(hua)(hua)(hua)鎂(mei)(mei)(mei)(mei)的純度(du)高達99.9%，在(zai)較(jiao)低溫(wen)度(du)下輕(qing)燒(shao)得氧(yang)化(hua)(hua)(hua)鎂(mei)(mei)(mei)(mei)粉末(mo)，而后經一定壓(ya)力壓(ya)球，制(zhi)(zhi)取(qu)高純電(dian)(dian)熔(rong)(rong)(rong)鎂(mei)(mei)(mei)(mei)砂。

電熔鎂(mei)砂(sha)熔煉過程研(yan)究

      電(dian)(dian)(dian)(dian)(dian)(dian)熔(rong)(rong)鎂(mei)砂熔(rong)(rong)煉(lian)工藝原理。電(dian)(dian)(dian)(dian)(dian)(dian)熔(rong)(rong)鎂(mei)砂是采用(yong)電(dian)(dian)(dian)(dian)(dian)(dian)弧(hu)熔(rong)(rong)融法(fa)進行制備(bei)，其裝(zhuang)備(bei)是電(dian)(dian)(dian)(dian)(dian)(dian)熔(rong)(rong)鎂(mei)電(dian)(dian)(dian)(dian)(dian)(dian)弧(hu)爐(lu)(礦熱埋(mai)弧(hu)電(dian)(dian)(dian)(dian)(dian)(dian)爐(lu))，即通過(guo)電(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)的埋(mai)弧(hu)電(dian)(dian)(dian)(dian)(dian)(dian)熱和物(wu)(wu)料(liao)的電(dian)(dian)(dian)(dian)(dian)(dian)阻電(dian)(dian)(dian)(dian)(dian)(dian)熱來熔(rong)(rong)煉(lian)物(wu)(wu)料(liao)。其電(dian)(dian)(dian)(dian)(dian)(dian)耗很大，爐(lu)體一般呈圓形，三根電(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)布置成(cheng)三角形。電(dian)(dian)(dian)(dian)(dian)(dian)熔(rong)(rong)鎂(mei)爐(lu)在生產過(guo)程中，是以電(dian)(dian)(dian)(dian)(dian)(dian)弧(hu)電(dian)(dian)(dian)(dian)(dian)(dian)熱對爐(lu)料(liao)加熱使(shi)之熔(rong)(rong)化(hua)，形成(cheng)熔(rong)(rong)池，電(dian)(dian)(dian)(dian)(dian)(dian)弧(hu)電(dian)(dian)(dian)(dian)(dian)(dian)熱越(yue)大，物(wu)(wu)料(liao)熔(rong)(rong)化(hua)的速度(du)越(yue)快。

      電(dian)熔(rong)鎂(mei)砂的制(zhi)備是以氫氧(yang)化鎂(mei)煅燒氧(yang)化鎂(mei)壓制(zhi)成球后為原(yuan)料(liao)，在4000kVA高(gao)溫(wen)電(dian)弧(hu)爐中(zhong)經冶煉(lian)、熔(rong)化再結(jie)晶(jing)后形成的鎂(mei)砂制(zhi)品(pin)，在不同類型的電(dian)弧(hu)爐中(zhong)通過(guo)電(dian)弧(hu)加熱產生高(gao)溫(wen)(≥2800℃)，使鎂(mei)質原(yuan)料(liao)在爐中(zhong)受熱、脫水(shui)(釆(bian)用水(shui)氯鎂(mei)石)、溶融、析晶(jing)、晶(jing)體長大、冷卻等一系列物理化學變化過(guo)程，形成一種(zhong)耐高(gao)溫(wen)、硬度大、純度高(gao)的電(dian)熔(rong)氧(yang)化鎂(mei)晶(jing)體。

      電(dian)熔(rong)(rong)鎂砂的(de)(de)(de)熔(rong)(rong)煉過程主要分為填料(liao)(liao)階(jie)(jie)(jie)段(duan)、起(qi)弧(hu)階(jie)(jie)(jie)段(duan)、熔(rong)(rong)融(rong)階(jie)(jie)(jie)段(duan)、加料(liao)(liao)階(jie)(jie)(jie)段(duan)、冷卻階(jie)(jie)(jie)段(duan)以(yi)及(ji)停(ting)爐(lu)階(jie)(jie)(jie)段(duan)：填料(liao)(liao)階(jie)(jie)(jie)段(duan)。在電(dian)熔(rong)(rong)開(kai)(kai)始工作(zuo)之(zhi)前(qian)需往(wang)爐(lu)內裝料(liao)(liao)，應(ying)做到將料(liao)(liao)壓實(shi)壓密，并在粉料(liao)(liao)的(de)(de)(de)最上層(ceng)(ceng)鋪一(yi)層(ceng)(ceng)工業冶金(jin)焦炭，其平鋪范圍在三根電(dian)極(ji)(ji)所形成的(de)(de)(de)三角形范圍內，使(shi)得起(qi)弧(hu)后電(dian)路形成回路;起(qi)弧(hu)階(jie)(jie)(jie)段(duan)。調節電(dian)極(ji)(ji)，開(kai)(kai)始進入起(qi)弧(hu)階(jie)(jie)(jie)段(duan);熔(rong)(rong)融(rong)階(jie)(jie)(jie)段(duan)。起(qi)弧(hu)后，待電(dian)流趨于平穩(wen)后，電(dian)極(ji)(ji)周圍的(de)(de)(de)原料(liao)(liao)開(kai)(kai)始熔(rong)(rong)融(rong)，熔(rong)(rong)池逐漸形成;加料(liao)(liao)階(jie)(jie)(jie)段(duan)。

      隨氧(yang)化鎂(mei)(mei)原料(liao)不斷消(xiao)耗，熔(rong)(rong)(rong)(rong)池液面(mian)開始下降，待熔(rong)(rong)(rong)(rong)池穩(wen)定(ding)后(hou)可往(wang)電極(ji)(ji)周(zhou)圍填料(liao)，進入(ru)(ru)加(jia)料(liao)階段(duan)(需注意不要(yao)破壞熔(rong)(rong)(rong)(rong)池的(de)穩(wen)定(ding)性);冷卻(que)階段(duan)。熔(rong)(rong)(rong)(rong)煉完成后(hou)，電極(ji)(ji)逐漸被氧(yang)化消(xiao)耗，電流減小。需通過冷卻(que)給(gei)熔(rong)(rong)(rong)(rong)池內(nei)的(de)氧(yang)化鎂(mei)(mei)晶(jing)體創造(zao)一個(ge)穩(wen)定(ding)散熱降溫的(de)環(huan)境，使其冷凝結(jie)晶(jing)出多晶(jing)氧(yang)化鎂(mei)(mei)產品(pin);停(ting)爐(lu)階段(duan)。停(ting)爐(lu)過程(cheng)中，往(wang)往(wang)采用(yong)手動加(jia)料(liao)，為了減少排氣，電極(ji)(ji)附近要(yao)加(jia)入(ru)(ru)氧(yang)化鎂(mei)(mei)坯砂(氧(yang)化鎂(mei)(mei)輕燒粉不含(han)CO2)，并多加(jia)細粉料(liao)，有利于產品(pin)產量及品(pin)質提高。電熔(rong)(rong)(rong)(rong)鎂(mei)(mei)砂熔(rong)(rong)(rong)(rong)融結(jie)晶(jing)過程(cheng)。

      電熔(rong)(rong)(rong)鎂砂的(de)(de)熔(rong)(rong)(rong)融(rong)(rong)結晶(jing)過(guo)程(cheng)伴隨著雜(za)質的(de)(de)遷移和析(xi)出(chu)，在熔(rong)(rong)(rong)煉(lian)過(guo)程(cheng)中，由于(yu)各組分(fen)的(de)(de)熔(rong)(rong)(rong)點(dian)和密度(du)不(bu)同，其析(xi)出(chu)方式存在差(cha)異(yi)：熔(rong)(rong)(rong)融(rong)(rong)開(kai)(kai)始時(shi)，隨溫(wen)度(du)的(de)(de)升(sheng)(sheng)(sheng)高，熔(rong)(rong)(rong)點(dian)較(jiao)低的(de)(de)雜(za)質先達到(dao)熔(rong)(rong)(rong)點(dian)溫(wen)度(du)，并轉變(bian)成液態(tai);隨溫(wen)度(du)繼續升(sheng)(sheng)(sheng)高，當達到(dao)氧(yang)(yang)化(hua)(hua)鎂熔(rong)(rong)(rong)點(dian)溫(wen)度(du)時(shi)，此時(shi)氧(yang)(yang)化(hua)(hua)鎂開(kai)(kai)始熔(rong)(rong)(rong)化(hua)(hua)，因氧(yang)(yang)化(hua)(hua)鎂的(de)(de)密度(du)相對較(jiao)高，其它雜(za)質的(de)(de)密度(du)相對較(jiao)低，加上(shang)(shang)熔(rong)(rong)(rong)池(chi)中二氧(yang)(yang)化(hua)(hua)碳和水蒸氣的(de)(de)不(bu)斷(duan)上(shang)(shang)升(sheng)(sheng)(sheng)，使得雜(za)質逐漸向上(shang)(shang)遷移。

      總之(zhi)，目前電熔鎂(mei)砂傳統生產(chan)(chan)工藝(yi)是以菱鎂(mei)礦為原料，通過電弧爐高(gao)(gao)溫熔煉制(zhi)備而成(cheng)，但該法存在產(chan)(chan)品質量不高(gao)(gao)、生產(chan)(chan)能耗高(gao)(gao)、環境污(wu)染(ran)嚴重、工作(zuo)強度(du)大等缺(que)陷。而利用鹽湖鹵水制(zhi)備的(de)(de)高(gao)(gao)純(chun)Mg(OH)2中間(jian)體為原料生產(chan)(chan)高(gao)(gao)純(chun)電熔鎂(mei)砂，具有產(chan)(chan)品附(fu)加值高(gao)(gao)、生產(chan)(chan)處理量大、能耗低等優異特點，解(jie)決了國內外高(gao)(gao)端鎂(mei)砂制(zhi)品的(de)(de)需(xu)求。因此(ci)，該工藝(yi)是今后高(gao)(gao)純(chun)電熔鎂(mei)砂制(zhi)備的(de)(de)主(zhu)流方向。

電熔鎂砂