- 期刊
褐鐵型紅土鎳礦提煉富鎳生鐵之研究
Study on Nickel Enrichment in Nickel Pig Iron Production during Reduction and Smelting of Limonite Laterite
摘要
鎳生鐵是不銹鋼冶煉的重要原料之一，世界鎳資源主要分為硫化鎳礦和氧化鎳礦，隨著硫化鎳礦資源的枯竭促進了氧化系紅土鎳礦的利用。紅土鎳礦生產鎳鐵的方法有濕法冶金和火法冶金，但工藝比較成熟的規模化生產仍以火法冶金為主。火法冶煉鎳鐵是在高溫條件下，以碳為還原劑，採用選擇性還原技術對鎳礦中的鎳鐵氧化物進行還原而得。本研究以褐鐵型紅土鎳礦（高鐵低鎳）生料及其煆燒後為原料，以石墨為還原劑，均混製成含碳複合球團，再利用碳熱還原－熔分方式製備出鎳鐵生鐵。為獲得較佳鎳鐵品位和鎳回收率之較適操作條件組合（溫度、時間、碳／氧莫耳比等），第1階段利用低溫煅燒程序消除褐鐵型紅土鎳礦晶格間的氫根和結晶水，使晶格間產生了更多細小縫隙來增加礦物表面積，加速氣固還原反應而提高金屬鎳產出速率；第2階段以煅燒後原料製備成含碳複合球團，再以適當溫度進行碳熱還原反應，產製預還原球團；第3階段則將預還原球團進行高溫鐵渣熔分，獲得高鎳生鐵，其鎳品位為＞15%，鎳回收率＞85%。
並列摘要
Nickel pig iron is one of the important raw materials for stainless steel smelting. On the earth, nickel ore reserves are divided into two categories: nickel sulfide ore and nickel oxide ore. Utilization of the oxidized laterite nickel ore is promoted with the depletion of nickel sulfide ore reserves. The methods of nickel-iron production using laterite nickel ore are divided into hydrometallurgy and pyrometallurgy. The relatively mature technology and mass production is still dominated by pyrometallurgy. In the pyrometallurgical smelting of nickel-iron, the selective reduction technology is adopted in the reduction of the nickel-iron oxide in the nickel ore using carbon as the reducing agent under high temperature. In this study, the limonite laterite (high-iron and low-nickel) was calcined firstly, then grinded and mixed with graphite which was used as reducing agent. The mixed powder was used to prepare carbon-containing composite pellets. To searching the production conditions (temperature, time, carbon/oxygen molar ratio, etc.) for both high grade ferronickel and high recovery ratio of nickel, a series experiments on the carbothermic reduction-smelting of the pellets were conducted in this study. At the first stage of this study, the limonite laterite was calcined at low temperature to eliminate hydrogen radicals and crystal water between crystal lattices of the nickel ore, resulting in more fine gaps between the crystal lattices, and increasing the specific surface area of the ore. It was found out that the calcination of the ore can accelerate the rate of gas-solid reduction inside the composite pellets, then facilitate the production of metallic nickel. At the second stage, the calcined ore was grinded and mixed with graphite powder, then granulated into carbon-containing pellets. The carbothermic reduction of the pellets was conducted at a suitable temperature to obtain the reduced pellets. At the third stage, the reduced pellets were processed with high-temperature melting and metal-slag separation to obtain the nickel pig iron. In this study, the nickel pig iron with nickel content ＞15%and the nickel recovery rate＞85% could be produced.