Phosphorus partitioning and recovery of low-phosphorus iron-rich compounds through physical separation of Linz-Donawitz slag  

作　　者：Dilip Makhija Rajendra Kumar Rath Kaushik Chakravarty Abhay Shankar Patra Asim Kumar Mukherjee Akhilesh Kumar Dubey 

机构地区：[1]Research and Development Division,Tata Steel Ltd. [2]Mineral Processing Division,CSIR-National Metallurgical Laboratory [3]Raw Material Blending and Bedding Section,Tata Steel Ltd.

出　　处：《International Journal of Minerals,Metallurgy and Materials》2016年第7期751-759,共9页矿物冶金与材料学报（英文版）

基　　金：the Research&Development Division and Management of Tata Steel Ltd.for their support and permission to publish this work

摘　　要：The Linz-Donawitz（LD） steelmaking process produces LD slag at a rate of about 125 kg/t. After metallic scrap recovery, the non-metallic LD slag is rejected because its physical/chemical properties are unsuitable for recycling. X-ray diffraction（XRD） studies have indicated that non-metallic LD slag contains a substantial quantity of mineral phases such as di- and tricalcium silicates. The availability of these mineral phases indicates that LD slag can be recycled by iron（Fe）-ore sintering. However, the presence of 1.2wt% phosphorus（P） in the slag renders the material unsuitable for sintering operations. Electron probe microscopic analysis（EPMA） studies indicated concentration of phosphorus in dicalcium silicate phase as calcium phosphate. The Fe-bearing phases（i.e., wustite and dicalcium ferrite） showed comparatively lower concentrations of P compared with other phases in the slag. Attempts were made to lower the P content of LD slag by adopting various beneficiation techniques. Dry high-intensity magnetic separation and jigging were performed on as-received samples with particle sizes of 6 and 3 mm. Spiral separation was conducted using samples ground to sizes of less than 1 and 0.5 mm. Among these studies, grinding to 0.5 mm followed by spiral concentration demonstrated the best results, yielding a concentrate with about 0.75wt% P and 45wt% Fe.The Linz-Donawitz（LD） steelmaking process produces LD slag at a rate of about 125 kg/t. After metallic scrap recovery, the non-metallic LD slag is rejected because its physical/chemical properties are unsuitable for recycling. X-ray diffraction（XRD） studies have indicated that non-metallic LD slag contains a substantial quantity of mineral phases such as di- and tricalcium silicates. The availability of these mineral phases indicates that LD slag can be recycled by iron（Fe）-ore sintering. However, the presence of 1.2wt% phosphorus（P） in the slag renders the material unsuitable for sintering operations. Electron probe microscopic analysis（EPMA） studies indicated concentration of phosphorus in dicalcium silicate phase as calcium phosphate. The Fe-bearing phases（i.e., wustite and dicalcium ferrite） showed comparatively lower concentrations of P compared with other phases in the slag. Attempts were made to lower the P content of LD slag by adopting various beneficiation techniques. Dry high-intensity magnetic separation and jigging were performed on as-received samples with particle sizes of 6 and 3 mm. Spiral separation was conducted using samples ground to sizes of less than 1 and 0.5 mm. Among these studies, grinding to 0.5 mm followed by spiral concentration demonstrated the best results, yielding a concentrate with about 0.75wt% P and 45wt% Fe.

关 键 词：steelmaking slag dephosphorization recycling 

分 类 号：X757[环境科学与工程—环境工程]