Abstract

Given the current depletion of the world's natural resources, the strong demand and the induced future deposit of primary mineral resources carrying metals (such as molybdenum, vanadium and chromium), one of the solution to this problem is the recycling of metals from by-products (such as steel slags) containing them. Steel slags are major by-products produced by the steel industry. Although they are considered as industrial waste that may cause public and environmental concerns, slags represent an important potential economic resource because they often contain significant amounts of valuable "Strategic Metals" (SMs). In order to minimize energy costs, environmental impacts and meet the metals demand for new high technologies, it will be more and more necessary to use cleaner and more economical technologies to recover these metals from slags. In this study, steel slags, generated from electrical arc furnace and provided by the Industeel France ArcelorMittal Company located in Châteauneuf (France), were studied. The chemical and mineralogical characterization results show that the investigated slags contain approximately 20–22% Fe, 3–4% Cr, 1 500 ppm V and are constituted of the following main crystalline phases: larnite (Ca₂SiO₄), magnetite (Fe₃O₄), wüstite (FeO) and chromite (FeCr₂O₄). Slag samples underwent different treatment steps before leaching (magnetic separation, grinding at d ≤ 25 μm and roasting). Various alkaline reagents (NaOH, KOH, Na₂CO₃ and K₂CO₃) have been studied with a slag/reagent weight ratio of 1, sufficiently high to provide an excess of alkaline reagent and allows the complete modification of the metal species able to be modified with these reagents at different co-grinding residence times. Three temperatures (400, 600 and 800 °C) were tested. The results show that the Cr leaching rate reaches 97.5% for one hour of the slag co-grinding with a NaOH and Na₂CO₃ mixture followed by roasting at 800 °C, while the V maximum leaching rate of 62.5% of vanadium is obtained after three hours of slag co-grinding with NaOH and Na₂CO₃ and roasted at 600 °C. The Mo leaching rate, meanwhile, reaches 95.8% using KOH for one hour of co-grinding the slag followed by roasting at 600 °C.

Graphic Abstract

中文翻译：

---

增强“电弧炉”（EAF）炉渣中有价金属回收率的方法

摘要

鉴于当前世界自然资源的枯竭，需求旺盛以及未来携带金属（例如钼，钒和铬）的主要矿产资源的诱生沉积，解决此问题的方法之一是回收副产品中的金属（例如钢渣）。钢渣是钢铁工业产生的主要副产品。尽管它们被视为可能引起公众和环境关注的工业废料，但由于它们通常包含大量的有价值的“战略金属”（SM），因此它们仍是重要的潜在经济资源。为了最大程度地减少能源成本，环境影响并满足金属对新高科技的需求，越来越有必要使用更清洁，更经济的技术从炉渣中回收这些金属。在这项研究中，研究了由电弧炉产生的钢渣，该钢渣是由位于法国沙特奥内夫（法国）的法国工业安赛乐米塔尔公司提供的。化学和矿物学表征结果表明，所研究的炉渣含有约20-22％的铁，3-4％的铬，1500 ppm V，并且由以下主要结晶相组成：菱铁矿（Ca₂的SiO ₄），磁铁矿（铁₃ Ò ₄），方铁矿（FeO计）和铬铁矿（铬铁₂ Ò ₄）。矿渣样品在浸出之前经历了不同的处理步骤（磁选，d≤25μm研磨和焙烧）。各种碱性试剂（NaOH，KOH，Na ₂ CO ₃和K ₂ CO ₃已经研究了渣/试剂重量比为1的高），足够高以提供过量的碱性试剂，并允许在不同的共研磨停留时间下完全改性能够用这些试剂改性的金属物质。测试了三个温度（400、600和800°C）。结果表明，与NaOH和Na ₂ CO ₃混合研磨1小时后，Cr渣的Cr浸出率达到97.5％，然后在800°C下焙烧，而钒的V最大浸出率为62.5％。炉渣与NaOH和Na ₂ CO ₃共研磨三个小时后，在600°C下烘烤。同时，使用KOH共研磨渣一小时，然后在600°C焙烧，Mo浸出率达到95.8％。

图形摘要