Arc Decomposition of Rhodonite

Abstract

A developmental pilot line for the arc treatment of Colorado rhodonite has been built and operated to investigate the applicability of the high-intensity arc process to the extraction of manganese from siliceous ores. The rhodonite is incorporated into 2-in. diameter electrodes to the extent of 75-85% by weight and vaporized in a d-c high-intensity arc operating in the range 40-60 kw. Vaporization in the arc decomposes the manganese silicate content of the rhodonite to MnO and SiO~. The product is collected as a mixture of the respective oxides in finely particulated form. The manganese, now readily soluble, is leached from this mixture. The effects of significant process variables are discussed.This paper describes the design and operation of a developmental pilot plant for the arc decomposition of Colorado rhodonite by means of a new process known as the Sheer-Xorman "Hierarc Process" (1, 2). The primary purposes of this program were to demonstrate the technical feasibility of treating rhodonite and to obtain process design and evaluation data.Rhodonite, a manganese silicate, is found in several sections of the United States and abounds in the southwestern area of Colorado. While deposits represent a significant quantity of Mn, the material is of such a refractory and stable nature that it has never been used as a major Mn source; instead it has been described as worthless gangue material in lead and zinc mining operations. Theoretically, pure rhodonite contains 42% Mn. Mined and milled in conjunction with lead-zinc operations, concentrates ranging up to 33, or perhaps 36% Mn, might be expected.The Hierarc Process, utilizing the high-intensity arc, serves to decompose the manganese silicate into a mixture of two discreet, finely particulated materials, manganous oxide and silica. In this form, the Mn is readily dissolved by leaching. For example, over 95% of the Mn in samples of arc product dissolved in dilute HC1 at room temperature.Using an anode consisting of an homogeneous mixture of ore and carbon--the ore content may be as high as 80-85%--the high-intensity arc provides an effective means of heating the material to temperatures of decomposition without the necessity of heating crucibles or other containing vessels.

Solar radiant heating of gas-particle mixtures. FY 1984 summary report

“…Two processes that offer possibilities for the STARR receiver are the refining of Colorado rhodonite (manganese silicate) to produce manganese oxide and silica, and the production of elemental phosphorus from phosphate rock. The first process was carried out at a temperature of about 1200 0 1( in an electric arc by Harris [22] and the second was demonstrated in a solar furnace by Whaley and Yudow [48]. Since the phosphorous reaction uses carbon as one of the initial reactants, it appears to be an excellent candidate for the STARR receiver.…”

Limit to erosion rate in a high-current carbon arc

“…Ea is approximately 12.5 V (Abrahamson et al, 1980), and 4> is 4.5 V, while E is usually between 50 and 70 V (Finkelnburg, 1946;Harris et al, 1959; Baddour and Iwasyk, 1962;Baddour and Blanchet, 1964;Wickens, 1976).…”

“…A high-intensity carbon arc can vaporize very refractory electrode material, and because of this it has been considered for a number of diverse processing applications. For example, acetylene has been produced from solid carbon and hydrogen (Baddour and Iwasyk, 1962; Baddour and Blanchet, 1964;Abrahamson, 1971;Ward, 1974); a high-intensity arc reactor has been used in the carbothermic reduction of rhodonite (Harris et al, 1959); several arc processes for reducing refractory ores have been proposed and patented (for example, Sheer and Korman, 1952, 1962, 1963Sheer et al, 1963); and a high-intensity arc reactor has been used in research on the production of particulate boron carbide (Wickens, 1976).…”

“…Industrially, the production of one kilogram of acetylene from gaseous and liquid feedstocks requires about 9.9 kWh (Lobo, 1961). Harris et al (1959) used 50 mm diameter composite anodes containing 16-18% carbon and 82-84% rhodonite and decomposed the rhodonite in the anode feedstock to MnO and Si02. The feed rate was only 2.5 g s'1 and the energy required was 8.5 kWh kg'1 of product, which is about six times as much energy as required by an alternative process that melted the rhodonite in a conventional arc furnace (Fuller et al, 1964).…”

Utilisation industrielle actuelle et potentielle des plasmas : synthèses, traitement des poudres, traitements métallurgiques, traitements de surface

“…La [155,156] dont l'évaluation économique [157] semble très encourageante pour les opérations de fonderie (coût énergétique de 3 kWh/kg conduisant à un coût de la tonne de fer pur voisin de celui du rond à béton). Ces études sont également reprises par la Kawasaki Steel Corp [158], la Foster Wheeler [159,160] [163], beryl [164,165], e récupération d'étain dans les laitiers par évapo-ration [166,167], e récupération de plomb dans les bains à base de silicate de plomb [168], e récupération de fer à partir de bauxite [169], e récupération de manganèse dans des bains à base de silicate de manganèse [170].…”