熔态铜渣“喷射气化脱硫-还原贫化”基础研究

The copper recovery rate of the existing cleaning process is low, and a large pile of copper slag, which is difficult to comprehensive utilization, has caused great security risks and brought heavy burden to the environment, therefore the efficient utilization of copper slag has become a worldwide problem in the copper metallurgy industry. The applicant has put forward a novel method of gasification desulfurization and selective reduction of molten copper slag by injection metallurgy, which could achieve the deep depletion of copper slag. The core of this approach is that the molten copper slag is desulfurized in gaseous form by the injection of oxidation mixed gases, then the metal oxide is selectively reduced to metal by the injection of reducing mixed gases. With the help of thermodynamic equilibrium calculations and numerical simulation, the method of multiple mixed gas injection into molten copper slag and the test platform of tube furnace with controllable atmosphere and cleaning furnace, the following experimental studies will be carried out in this application. The distribution of Cu and S in the phase of the melting copper slag and gas will be studied. The coupling effect of S, O and C(H) et al on the change of phase containing Cu in molten slag will be revealed. The mechanism of oxidation atmosphere controlling gasification desulfurization will be explored. The selective reduction of metal oxides by reducing agent (CH4-H2-CO) will be understood. The three-dimensional multiphase flow model of the multi-component mixed gases injection into molten slag will be established. The key injection parameters of gasification desulfurization and selective reduction will be determined. The goal , wCu<0.15%, will be achieved for the deep depletion of copper slag. This paper will provide theoretical basis and data support for the application of gasification desulfurization and selective reduction of molten copper slag by injection metallurgy.

现有铜渣贫化工艺铜回收率低，含铁弃渣大量堆放难以综合利用，造成安全隐患，并给环境带来沉重负担，铜渣高效资源化利用已成为铜冶金行业的世界性难题。申请人提出采用喷吹多元混合气体，对熔态铜渣进行气化脱硫与选择性还原，实现铜渣深度贫化的“喷射气化脱硫-还原贫化”新方法。通过热力学计算和数值模拟等手段，依托可控气氛管式炉与自主搭建的贫化电炉试验平台，研究与气相达到热力学平衡时熔态铜渣中Cu、Fe、S等元素的分布特征，揭示S、O、C(H)等元素间耦合作用对熔渣中含Cu物相转变的影响规律，探明炉内氧化气氛控制气化脱硫机理，掌握还原气氛（CH4-H2-CO）对Cu、Fe等金属氧化物的选择性还原规律，构建多元混合气体射流进入熔池的三维全尺寸多相流耦合模拟模型，确定气化脱硫与还原贫化关键性喷吹参数，稳定实现铜渣深度贫化（wCu＜0.15%），为熔态铜渣“喷射气化脱硫-还原贫化”方法应用提供理论依据和数据支撑。

通过基础研究，掌握了熔态铜渣喷射气化脱硫-还原贫化过程中的基本反应机理，研究了氧化脱硫及选择性还原下渣中Cu-Fe-S-O的物相转化及相界面迁移机制，探究了低硫含量下硫含量对Fe-Cu-S-O-Si体系的平衡变化规律。在基础研究之上，开展了铜渣气化脱硫-还原工艺应用研究，研究了多场耦合作用下铜渣中有害元的的迁移规律，并讨论了改工艺在其他有色渣系的适应性与推广应用价值。通过数值模拟与水模拟研究手段，确定试验的关键性喷吹参数，为试验及推广提供了理论基础。气化脱硫-还原贫化的中试实验研究论证了改工艺的可行性及推广应用价值，还原后尾渣含铜量约为0.3~0.4%，优于目前火法贫化工艺