(1. 昆明理工大學(xué) 省部共建復(fù)雜有色金屬資源清潔利用國家重點(diǎn)實(shí)驗(yàn)室，昆明 650093；
2. 昆明理工大學(xué) 冶金與能源工程學(xué)院，昆明 650093；
3. 云南銅業(yè)股份有限公司，昆明 650102；
4. 云南銅業(yè)(集團(tuán))有限公司，昆明 650102)
摘 要: 在分析石灰鐵鹽法含砷石膏渣的物相組成和浸出毒性基礎(chǔ)上，開展石膏渣-煤粉的TG-DSC和固-固反應(yīng)研究，探索石膏渣碳熱還原分解行為及砷遷移規(guī)律。結(jié)果表明：石膏渣在1000 ℃時(shí)的質(zhì)量損失率接近50%，石膏渣與煤粉質(zhì)量比為40:1時(shí)能夠有效促進(jìn)熱分解，具有較高的質(zhì)量損失率；石膏渣-煤粉反應(yīng)過程中，分解殘?jiān)霈F(xiàn)CaSO4→CaS→CaO的物相轉(zhuǎn)變，還原分解后期CaSO4→CaO/SO2轉(zhuǎn)變較為徹底，揮發(fā)率為45.29%、減容率為65.83%，氣體產(chǎn)物成分為SO2和CO2，揮發(fā)性煙塵主要成分為As2O3；分解殘?jiān)⒂^結(jié)構(gòu)較為致密，砷浸出毒性為1.05mg/L低于《GB 5085.1－2007》限值，浸出率僅為原石膏渣的1/236，殘留的63.38%砷被有效固化在分解殘?jiān)小Ｌ紵徇€原分解實(shí)現(xiàn)石膏渣的無害化處置、硫資源利用和砷的富集。
關(guān)鍵字: 含砷石膏渣；碳熱還原分解；TG-DSC；浸出毒性
（1. State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming 650093, China;
2. Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China;
3. Yunnan Copper Co., Ltd., Kunming 650102, China;
4. Yunnan Copper (Group) Co., Ltd., Kunming 650102, China）
Abstract:On the basis of chemical composition, phase, leaching toxicity and thermal stability of arsenic bearing gypsum sludge obtained in lime/ferrous sulfate precipitation process, the reductive decomposition characteristics and arsenic migration rule were investigated by TG-DSC and solid-solid reaction between arsenic bearing gypsum sludge and coal. The results show that mass loss ratio of 50% is obtained when temperature reaches to 1000 ℃. A sludge/coal mass ratio of 40:1 can effectively promote the thermal decomposition and lead to a higher mass loss rate. The CaSO4→CaS→CaO phase transformation occurs during the reductive decomposition process of gypsum sludge/coal. The transformation of CaSO4→CaO/SO2 proceeds completely and a volatilization rate of 45.29% and a volume reduction rate of 65.83% are obtained in the final stage. The evolved gas is consistent with SO2 and CO2 while As2O3 is the main phase of dust. The reacted residue is characterized with dense structure. The arsenic concentration in leaching toxicity test of the reacted residue is 1.05 mg/L which is lower than limit in GB 5085.1—2007. It is found that 63.38% of total arsenic remained in the reacted residue but with a low arsenic leaching rate (1/236 of arsenic leaching rate in gypsum sludge). The reductive decomposition of arsenic bearing gypsum sludge realizes the harmless disposal, sulphur utilization and arsenic enrichment.
Key words: arsenic bearing gypsum sludge; reductive decomposition; TG-DSC; leaching toxicity
