Selective Precipitation of Manganese in the Processing of Phosphorus-Bearing Ferromanganese Nodules

Abstract

669.053 A. A. Dar'in, and N. M. Telyakov A description is given of a technology for processing deep-water ferromanganese nodules in the Baltic Sea with the use of sulfatizing roasting. It is shown that the use of this technology makes it possible to recover manganese in solution without the transfer of phosphorus to the solution as well. Results are reported from studies of the precipitation of manganese by ammonia during the subsequent processing of phosphorusbearing ferromanganese nodules (FMN). The results show that manganese can be precipitated by a hydrometallurgical method after sulfatizing roasting is completed as part of FMN processing.To solve the problem of providing Russian industry with manganese-bearing raw materials -most of which are currently imported -it will be necessary to develop a technology that can make pure manganese products from phosphorus-bearing ferromanganese nodules. The total reserves of submarine ores in the ocean exceed 1.6·10 12 tons, while the size of the ore deposits in the Eastern Finland ore region is estimated to be 12 million tons [1].A phosphorus content of 1.5-4.0% distinguishes the shelf ferromanganese nodules (SFMNs) in the Gulf of Finland -which lie at a depth of about 30-70 m -from the submarine nodules in the ocean (at a depth of more than 1000 m) [2]. The phosphorus is an unacceptable impurity in fi nished products such as ferromanganese (which is used to deoxidize steel in steelmaking). In addition, the SFMNs lack sizable contents of nonferrous metals.One requirement that the technology will have to meet is separation of the phosphorus and manganese during the processing of the nodules, this being necessary to satisfy existing requirements on the content of phosphorus compounds in the commercial product. It is also necessary to consider the possibility of the formation of hard-to-fi lter solutions during leaching due to the substantial quantity of silica that is present in the composition.The Department of Furnace Technologies and the Processing of Energy Carriers at Gornyi University has analyzed the sulfuric-acid method of processing nodules and the method of sulfatizing roasting in a fl uidized bed followed by selective leaching. The results of studies have shown that technologies which do not include roasting are inadequate as an independent operation for processing certain compositions of phosphorus-bearing ferromanganese nodules (FMNs) from the Baltic sea. The main shortcoming of these technologies is the transfer of phosphorus to the solution after the leaching operation, which makes it necessary to create other conditions to separate and fi lter the solutions. The advantage of the pyrometallurgical technology (sulfatizing roasting in a fl uidized bed and subsequent selective leaching) is that manganese and phosphorus are separated from one another within the roasting-temperature range (400-800°C) while they are in their original form of Ca 3 (PO 4 ) 2 and the phosphorus is transferred to the cake during the fi ltration stage.Scaled-up laboratory tests of su...

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Investigation of Sulfatization Mechanism of Iron-Manganese Concretions in Fluidized Bed

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Use of tailings in mn dissolution from marine nodule matrix

“…71percent of the total surface of the earth is covered by the oceans, where most of the seafloor reveals mineral deposits of economic interest, such as cobalt-rich crusts, polymetallic hydrometallurgical sulphides, and manganese nodules, reaching 1 to3 billion tonsof majormetal reserves can be found, such as Cu, Ni, Co, Fe and Mn, where the latter is most abundant, with an average content of around 24% [1]. [2]have installed pilot equipment that provides a realistic opportunity for marine nodules extraction, and previous studies,such as those carried out by [3]have already established that hydrometallurgical processes are a viablealternative for processing this mineral matrix, where manganese is obtained by selective precipitation after sulphating roasting.The use of iron as a reducing agent stands out by the abundance and positive results as shown by the authors over the past 20 years [4,5,6]. [7]investigated the effect of working with elemental Fe as a reducing agent at low H 2 SO 4 rates.…”