萬寧電熔鎂砂是(shi)重要的(de)工(gong)業原(yuan)材料(liao)，其(qi)生(sheng)產工(gong)藝簡單，主要以氧化(hua)鎂(mei)壓球料(liao)為原(yuan)料(liao)，采用電(dian)弧爐熔(rong)融法制(zhi)備而成。我國電(dian)熔(rong)鎂(mei)砂制(zhi)備工(gong)藝技術方面(mian)的(de)研(yan)究(jiu)成果，主要表現(xian)在選擇適宜(yi)的(de)化(hua)學添(tian)加劑改善鎂(mei)砂的(de)性能以及高效(xiao)新工(gong)藝的(de)開發。

我國電熔鎂砂制(zhi)備工藝(yi)及應用

      我國電熔鎂砂制備優化(hua)(hua)(hua)工藝(yi)。當前我國電熔鎂產(chan)業(ye)(ye)仍在沿(yan)用電弧爐生(sheng)產(chan)方式，技(ji)術(shu)(shu)(shu)裝(zhuang)備相對(dui)落后，效(xiao)率低，能(neng)源浪費嚴重，余熱(re)潛能(neng)流(liu)失嚴重;電熔鎂砂生(sheng)產(chan)過程中還(huan)存在著嚴重的粉塵(chen)污染，并大(da)量(liang)排放(fang)二氧化(hua)(hua)(hua)碳，加重了大(da)氣(qi)溫室效(xiao)應(ying)，惡(e)化(hua)(hua)(hua)周邊(bian)環(huan)境(jing)。現有(you)電熔鎂技(ji)術(shu)(shu)(shu)裝(zhuang)備亟待更新(xin)換代，現有(you)工藝(yi)急需(xu)創(chuang)新(xin)，因此，采用集成(cheng)技(ji)術(shu)(shu)(shu)發展(zhan)節能(neng)環(huan)保的新(xin)式電熔鎂裝(zhuang)備及制備工藝(yi)是發展(zhan)電熔鎂產(chan)業(ye)(ye)的重要(yao)選擇。

      近(jin)年來(lai)，國內的(de)科技工作者在(zai)電(dian)熔(rong)(rong)鎂(mei)(mei)砂(sha)(sha)的(de)生產(chan)(chan)工藝方面進行了改進和優化(hua)(hua)，并取得了一(yi)定的(de)成效。電(dian)熔(rong)(rong)鎂(mei)(mei)砂(sha)(sha)的(de)生產(chan)(chan)工藝流程(cheng)短而簡單，但設備投入和資源消耗大。我國電(dian)熔(rong)(rong)鎂(mei)(mei)砂(sha)(sha)產(chan)(chan)業多(duo)采用電(dian)弧爐熔(rong)(rong)融天然菱鎂(mei)(mei)礦石制備電(dian)熔(rong)(rong)鎂(mei)(mei)砂(sha)(sha)，生產(chan)(chan)工藝技術裝備落(luo)后(hou)(hou)，功率(lv)低(di)、容量小、效率(lv)低(di)、自動化(hua)(hua)程(cheng)度低(di)，生產(chan)(chan)出的(de)電(dian)熔(rong)(rong)鎂(mei)(mei)砂(sha)(sha)產(chan)(chan)品(pin)品(pin)位不高，導致(zhi)鎂(mei)(mei)資源利用率(lv)低(di)，環境污(wu)染嚴(yan)重(zhong)。通過(guo)(guo)利用鹽湖鹵水與氨氣反應后(hou)(hou)生成氫氧化(hua)(hua)鎂(mei)(mei)在(zai)煅燒(shao)后(hou)(hou)生成輕質氧化(hua)(hua)鎂(mei)(mei)，可以通過(guo)(guo)洗滌、過(guo)(guo)濾等(deng)方法有(you)效地(di)除去雜(za)質離(li)子，氧化(hua)(hua)鎂(mei)(mei)的(de)純度高達99.9%，在(zai)較(jiao)低(di)溫度下輕燒(shao)得氧化(hua)(hua)鎂(mei)(mei)粉末，而后(hou)(hou)經一(yi)定壓力(li)壓球，制取高純電(dian)熔(rong)(rong)鎂(mei)(mei)砂(sha)(sha)。

電熔(rong)鎂砂熔(rong)煉過程研究

      電(dian)(dian)熔(rong)(rong)(rong)鎂(mei)砂熔(rong)(rong)(rong)煉工藝原理。電(dian)(dian)熔(rong)(rong)(rong)鎂(mei)砂是采用電(dian)(dian)弧熔(rong)(rong)(rong)融法進行(xing)制備，其(qi)裝(zhuang)備是電(dian)(dian)熔(rong)(rong)(rong)鎂(mei)電(dian)(dian)弧爐(lu)(lu)(lu)(礦熱埋弧電(dian)(dian)爐(lu)(lu)(lu))，即(ji)通過(guo)電(dian)(dian)極(ji)的埋弧電(dian)(dian)熱和物料的電(dian)(dian)阻(zu)電(dian)(dian)熱來熔(rong)(rong)(rong)煉物料。其(qi)電(dian)(dian)耗很大(da)，爐(lu)(lu)(lu)體一(yi)般(ban)呈圓(yuan)形(xing)，三根(gen)電(dian)(dian)極(ji)布置成(cheng)(cheng)三角形(xing)。電(dian)(dian)熔(rong)(rong)(rong)鎂(mei)爐(lu)(lu)(lu)在生產過(guo)程(cheng)中，是以電(dian)(dian)弧電(dian)(dian)熱對(dui)爐(lu)(lu)(lu)料加熱使之(zhi)熔(rong)(rong)(rong)化，形(xing)成(cheng)(cheng)熔(rong)(rong)(rong)池(chi)，電(dian)(dian)弧電(dian)(dian)熱越大(da)，物料熔(rong)(rong)(rong)化的速度越快。

      電(dian)熔(rong)(rong)鎂(mei)(mei)(mei)砂的制(zhi)備是以(yi)氫氧化(hua)鎂(mei)(mei)(mei)煅燒氧化(hua)鎂(mei)(mei)(mei)壓(ya)制(zhi)成球后為原(yuan)(yuan)料，在4000kVA高溫(wen)電(dian)弧爐中(zhong)經冶煉(lian)、熔(rong)(rong)化(hua)再(zai)結晶(jing)后形成的鎂(mei)(mei)(mei)砂制(zhi)品，在不(bu)同類型的電(dian)弧爐中(zhong)通過電(dian)弧加(jia)熱產生高溫(wen)(≥2800℃)，使鎂(mei)(mei)(mei)質(zhi)原(yuan)(yuan)料在爐中(zhong)受(shou)熱、脫水(釆用(yong)水氯鎂(mei)(mei)(mei)石)、溶(rong)融、析晶(jing)、晶(jing)體(ti)長大(da)(da)、冷卻(que)等一(yi)系列(lie)物理化(hua)學變化(hua)過程，形成一(yi)種耐高溫(wen)、硬度(du)大(da)(da)、純度(du)高的電(dian)熔(rong)(rong)氧化(hua)鎂(mei)(mei)(mei)晶(jing)體(ti)。

      電(dian)(dian)熔(rong)(rong)(rong)(rong)(rong)鎂砂的(de)熔(rong)(rong)(rong)(rong)(rong)煉(lian)過程主(zhu)要分為填料(liao)(liao)(liao)(liao)(liao)階(jie)(jie)(jie)(jie)(jie)(jie)(jie)段(duan)(duan)(duan)、起弧(hu)階(jie)(jie)(jie)(jie)(jie)(jie)(jie)段(duan)(duan)(duan)、熔(rong)(rong)(rong)(rong)(rong)融(rong)(rong)階(jie)(jie)(jie)(jie)(jie)(jie)(jie)段(duan)(duan)(duan)、加料(liao)(liao)(liao)(liao)(liao)階(jie)(jie)(jie)(jie)(jie)(jie)(jie)段(duan)(duan)(duan)、冷卻階(jie)(jie)(jie)(jie)(jie)(jie)(jie)段(duan)(duan)(duan)以及(ji)停爐(lu)階(jie)(jie)(jie)(jie)(jie)(jie)(jie)段(duan)(duan)(duan)：填料(liao)(liao)(liao)(liao)(liao)階(jie)(jie)(jie)(jie)(jie)(jie)(jie)段(duan)(duan)(duan)。在(zai)電(dian)(dian)熔(rong)(rong)(rong)(rong)(rong)開始(shi)工作(zuo)之前需往(wang)爐(lu)內(nei)裝(zhuang)料(liao)(liao)(liao)(liao)(liao)，應做到(dao)將(jiang)料(liao)(liao)(liao)(liao)(liao)壓實(shi)壓密，并(bing)在(zai)粉料(liao)(liao)(liao)(liao)(liao)的(de)最上層(ceng)(ceng)鋪一層(ceng)(ceng)工業(ye)冶(ye)金焦(jiao)炭，其平鋪范圍(wei)(wei)在(zai)三(san)根電(dian)(dian)極(ji)所(suo)形(xing)(xing)成的(de)三(san)角形(xing)(xing)范圍(wei)(wei)內(nei)，使得起弧(hu)后(hou)電(dian)(dian)路(lu)形(xing)(xing)成回路(lu);起弧(hu)階(jie)(jie)(jie)(jie)(jie)(jie)(jie)段(duan)(duan)(duan)。調節(jie)電(dian)(dian)極(ji)，開始(shi)進(jin)入起弧(hu)階(jie)(jie)(jie)(jie)(jie)(jie)(jie)段(duan)(duan)(duan);熔(rong)(rong)(rong)(rong)(rong)融(rong)(rong)階(jie)(jie)(jie)(jie)(jie)(jie)(jie)段(duan)(duan)(duan)。起弧(hu)后(hou)，待電(dian)(dian)流趨于平穩后(hou)，電(dian)(dian)極(ji)周圍(wei)(wei)的(de)原料(liao)(liao)(liao)(liao)(liao)開始(shi)熔(rong)(rong)(rong)(rong)(rong)融(rong)(rong)，熔(rong)(rong)(rong)(rong)(rong)池(chi)逐漸形(xing)(xing)成;加料(liao)(liao)(liao)(liao)(liao)階(jie)(jie)(jie)(jie)(jie)(jie)(jie)段(duan)(duan)(duan)。

      隨氧(yang)(yang)(yang)化鎂(mei)原料(liao)不斷消耗(hao)，熔(rong)池液面開(kai)始下(xia)降(jiang)，待熔(rong)池穩定(ding)后(hou)可往(wang)電(dian)(dian)(dian)極周圍填料(liao)，進入加(jia)料(liao)階(jie)段(需(xu)注意不要(yao)破壞熔(rong)池的(de)穩定(ding)性);冷(leng)卻階(jie)段。熔(rong)煉(lian)完成后(hou)，電(dian)(dian)(dian)極逐漸被氧(yang)(yang)(yang)化消耗(hao)，電(dian)(dian)(dian)流減小(xiao)。需(xu)通過冷(leng)卻給熔(rong)池內(nei)的(de)氧(yang)(yang)(yang)化鎂(mei)晶(jing)體創造一個穩定(ding)散熱降(jiang)溫的(de)環境，使其冷(leng)凝結(jie)晶(jing)出多(duo)晶(jing)氧(yang)(yang)(yang)化鎂(mei)產品;停爐(lu)階(jie)段。停爐(lu)過程中，往(wang)往(wang)采用手動加(jia)料(liao)，為了減少排氣(qi)，電(dian)(dian)(dian)極附(fu)近要(yao)加(jia)入氧(yang)(yang)(yang)化鎂(mei)坯砂(氧(yang)(yang)(yang)化鎂(mei)輕燒(shao)粉不含CO2)，并多(duo)加(jia)細粉料(liao)，有利(li)于產品產量及品質(zhi)提高。電(dian)(dian)(dian)熔(rong)鎂(mei)砂熔(rong)融結(jie)晶(jing)過程。

      電(dian)熔(rong)鎂(mei)(mei)砂(sha)的熔(rong)融結晶過程(cheng)伴隨(sui)著雜質(zhi)的遷移(yi)(yi)和(he)析出，在(zai)熔(rong)煉(lian)過程(cheng)中(zhong)，由于各組分的熔(rong)點和(he)密(mi)度不同，其(qi)析出方式(shi)存在(zai)差(cha)異：熔(rong)融開(kai)始(shi)時(shi)，隨(sui)溫(wen)度的升高(gao)，熔(rong)點較(jiao)低(di)的雜質(zhi)先達到熔(rong)點溫(wen)度，并轉(zhuan)變成液態;隨(sui)溫(wen)度繼續升高(gao)，當達到氧化(hua)鎂(mei)(mei)熔(rong)點溫(wen)度時(shi)，此(ci)時(shi)氧化(hua)鎂(mei)(mei)開(kai)始(shi)熔(rong)化(hua)，因氧化(hua)鎂(mei)(mei)的密(mi)度相(xiang)對較(jiao)高(gao)，其(qi)它雜質(zhi)的密(mi)度相(xiang)對較(jiao)低(di)，加上熔(rong)池中(zhong)二(er)氧化(hua)碳和(he)水蒸氣(qi)的不斷上升，使得雜質(zhi)逐(zhu)漸向上遷移(yi)(yi)。

      總之，目前(qian)電(dian)(dian)熔鎂(mei)砂傳統(tong)生產(chan)(chan)工(gong)藝是以菱鎂(mei)礦為原料，通(tong)過電(dian)(dian)弧(hu)爐高(gao)(gao)溫熔煉制(zhi)備而(er)成(cheng)，但(dan)該法(fa)存在產(chan)(chan)品(pin)質量不(bu)高(gao)(gao)、生產(chan)(chan)能耗(hao)高(gao)(gao)、環境污染嚴重、工(gong)作強度(du)大(da)等缺陷。而(er)利用鹽湖鹵水(shui)制(zhi)備的高(gao)(gao)純(chun)(chun)Mg(OH)2中間(jian)體為原料生產(chan)(chan)高(gao)(gao)純(chun)(chun)電(dian)(dian)熔鎂(mei)砂，具有產(chan)(chan)品(pin)附加值高(gao)(gao)、生產(chan)(chan)處理量大(da)、能耗(hao)低(di)等優異特點，解決了國內外高(gao)(gao)端鎂(mei)砂制(zhi)品(pin)的需求。因(yin)此，該工(gong)藝是今后高(gao)(gao)純(chun)(chun)電(dian)(dian)熔鎂(mei)砂制(zhi)備的主流方(fang)向(xiang)。

電熔鎂砂