转炉预脱磷与“全三脱”铁水少渣冶炼技术

京唐公司炼钢系统铁水转炉预脱磷及“全三脱”铁水少渣冶炼工艺不断进行技术优化，脱磷转炉通过优化废钢尺寸、底吹枪数量和排布，半钢脱磷率可达到70%；铁水经过脱磷转炉脱硅、脱磷后，温度和磷质量分数更加稳定，为脱碳转炉少渣冶炼、自动化炼钢终点双命中率的提高提供了先决条件；脱碳转炉通过采用留渣操作、少渣冶炼技术、溅渣护炉技术后，自动化命中率达到90%以上，炉龄达到7000炉以上；炼钢车间内渣钢、除尘灰、氧化铁皮等含铁物料实现了自循环消耗。采用“全三脱”铁水冶炼工艺，钢种质量进一步提高，超低磷与超低硫钢中（S＋P＋N）元素质量分数可稳定控制在0.0095%以下。

Dephosphorization pretreatment in LD converter and less-slag steelmaking process

The technology of hot metal dephosphorization pretreatment and less-slag steelmaking process was opti-mized step by step in Shougang Jingtang. The dephosphorization rate could reach 70%through the optimization of scrap size,bottom tuyer number and arrangement in De-P converter. The steady temperature and P content in semi-steel after the pretreatment in De-P converter can provide a good condition for the less-slag steelmaking and automatic steelmaking to achieve double hit ratios by steelmaking end. By the measurements,such as keeping slag operation,less-slag steelmak-ing and slag splashing technology,the automatic end-point aim can reach 90%and the lining life was more than 7 000. All the materials containing Fe,such as steel containing slag,precipitator dust,scales and so on,were all recycled in steelmaking plant. Through the dephosphorization pretreatment and less-slag steelmaking process,the quality of steel im-proved,the total content of S,P,N can reach less than 0.009 5%in ultra-low P and S steel grades.