A novel process for recovering manganese (Mn) values from two types of ferromanganese (FeMn) fumes (wastes from smelters) was developed incorporating several stages of leaching, roasting, and precipitation. Fumes containing high K (as K₂O) were first leached in water at ambient conditions to recover K, purified to remove metal impurities, and precipitated as 99.9% pure K₂SO₄. The residues containing Mn and remaining impurities were then leached in sulfuric acid at 80 °C using oxalic acid as reductant yielding Mn sulphate liquors. The leach liquors were then purified to remove Fe at 95°C as jarosite at pH 2.8 and Fe(III) hydroxides at pH 5.5. Base and transition metal impurities were removed as sulfides. K, Na, Ca, and Mg were separated from Mn in a novel step based on precipitation of Mn hydroxide from the Mn sulphate liquors. Subsequent redissolution of Mn hydroxide in sulfuric acid under reducing conditions using oxalic acid produced a high purity Mn sulphate liquors containing <5 ppm of these impurities. After evaporation by boiling manganese sulphate monohydrate (MSM) was crystallized, achieving purity >99.5%. Another fume containing oil contaminants having low K was subjected to sulfation roasting to produce Mn sulphate. The calcine was water leached to produce Mn sulfate liquors and treated in a similar process to make high purity MSM. Novelty aspects of the proposed process include the recovery of K as a by-product and separation of Mn²⁺ from other impurities by its selective precipitation to produce a high purity Mn sulphate solution for MSM recovery.

Implications: Ferro-manganese smelters discharge wastes (fumes) that are collected by bag filters or electrostatic precipitators and then store them on the ground with coverage to prevent their dispersion into the surrounding atmosphere. The work presented propose a process to reprocess these wastes into high purity manganese sulphate monohydrate (MSM). Processing of wastes containing high potassium as KOH also yields high purity potassium sulfate used as fertilizers. Some smelters spray oil onto the fume dumps to prevent material being blown onto the surrounding area. The oil-contaminated fumes have to be first roasted to burn off the oil, before they can be processed. The process developed therefore converts a hazardous waste into high purity MSM and potassium sulphate used in many applications.

开发了一种从两种类型的锰铁（FeMn）烟气（冶炼厂产生的废料）中回收锰（Mn）值的新方法，该方法包含了浸出，焙烧和沉淀的多个阶段。首先在环境条件下在水中浸出含高K（以K ₂ O计）的烟气以回收K，纯化以去除金属杂质，并以99.9％的纯K ₂ SO ₄沉淀。。然后使用草酸作为还原剂，在80°C的硫酸中浸出含有Mn和残留杂质的残留物，得到Mn硫酸盐溶液。然后提纯浸出液，以在95℃下去除铁（pH值为2.8的黄铁矿）和在pH值为5.5的氢氧化铁（III）。贱金属和过渡金属杂质作为硫化物被去除。K，Na，Ca和Mg在基于硫酸锰溶液中氢氧化锰沉淀的新步骤中与锰分离。随后使用草酸在还原条件下将氢氧化锰氢氧化物再溶解在硫酸中，制得了高纯度的硫酸锰溶液，其中含有＜5 ppm的这些杂质。通过沸腾蒸发蒸发后，硫酸锰一水合物（MSM）结晶，获得纯度> 99.5％。将另一种含有低K油污染物的烟气进行硫酸盐焙烧，以生产硫酸锰。煅烧煅烧水以生产硫酸锰液，并以类似的方法处理以制备高纯度MSM。拟议工艺的新颖性包括回收作为副产物的钾和分离锰通过选择性沉淀从其他杂质中分离出^2+离子，以生产用于MSM回收的高纯度硫酸锰溶液。

含义：锰铁冶炼厂排出的垃圾（烟气）由袋式除尘器或静电除尘器收集，然后将其覆盖在地面上，以防止其散布到周围的大气中。提出的工作提出了一种将这些废物重新加工成高纯度硫酸锰一水合物（MSM）的方法。加工含有高钾作为KOH的废物也可产生用作肥料的高纯度硫酸钾。一些冶炼厂将油喷到烟囱上，以​​防止物料吹到周围区域。在处理油之前，必须先将油污染的烟气烧掉，以燃烧掉油。因此，开发的工艺将危险废物转化为许多应用中使用的高纯度MSM和硫酸钾。