RU2266970C2 - Method of reduction of iron-manganese concretions of baltic sea - Google Patents

Abstract

FIELD: chemical concentration of manganese ores; reduction of iron-manganese concretions.

SUBSTANCE: proposed method includes heating of ores together with reductant for reducing manganese dioxide (MnO₂) to bivalent state (MnO). Subjected to reducing roasting are iron-manganese concretions of Baltic Sea containing no more than 26% of MnO₂ with the use of organic agents as reductants contained in the amount of 14% at heating to temperature of 400°C and limited admission of air to roasting zone.

EFFECT: simplified procedure of reducing roasting.

1 dwg, 1 ex

Description

The invention relates to the field of chemical enrichment of manganese ores, and more particularly to the production of chemical concentrates from iron-manganese nodules (LMF) of the Baltic Sea.

Most of the technologies for chemical enrichment of manganese ores include, as a first step, the transition of manganese oxides into solution in the form of manganese sulfates, nitrates or chlorides. To implement the simplest process of extracting manganese oxides with acid, it is necessary to restore manganese from four to a divalent form.

A large number of methods for the reduction of oxide ores are known:

a) firing at high temperature in a gas reducing medium (hydrogen, natural gas, carbon monoxide) (Shkurov AS Development of electrolyte technology in the production of manganese dioxide. Abstract. L., 1991);

c) firing in a mixture with elemental sulfur, pyrite cinder, iron filings (Physical and chemical foundations of manganese metallurgy. Science, 1977, p. 122, 127);

d) firing in a mixture with organic substances - coal, wood sawdust.

All of these processes require a rather complicated hardware design, thorough mixing with the introduced reagents, high temperatures.

Closest to the proposed method, the prototype is the roasting of manganese ore with a reducing agent.

This method, like all others, requires careful mixing of ore with a reducing reagent, high temperature, contaminates the sludge with a large amount of ash, requires maintaining a reducing atmosphere in the furnace when cooled to 100 ° C.

The technical result of the invention is to simplify the process of reductive roasting. The technical result is achieved by a method of reductive roasting of iron-manganese nodules, including heating them with a reductant to reduce manganese dioxide (MnO ₂ ) to a divalent state (MnO), according to the invention, re-calcination of iron-manganese nodules of the Baltic is carried out. sea containing MnO ₂ is not more than 26%, using as a reducing agent of organic substances contained in their composition in quantitative e an average of 14%, when heated to a temperature of 400 ° C with access of air to the burning zone restricted.

Example.

In a glass vessel with a capacity of 0.5 l, ground up to 1 mm LMF is poured flush with the edges and closed with a lid that restricts air circulation, but allows vapors and gases to escape. In the oven, the vessel is kept for 1 hour at T = 380 ° C, not counting the heating time.

To identify thermal effects, a temperature curve was taken (see figure 1). An exposure of 100 ° C corresponds to the process of removing free moisture. The next stage is the rapid heating of the product to 320 ° C due to the exothermicity of the manganese recovery reaction. At the fourth stage, the recovery process ends and the temperature rise is ensured only due to external heat.

To complete the firing process, it is necessary to cool the LMC to at least 200 ° C while restricting air access to prevent oxidation of the product. In our example, this is done by standing the vessel outside the oven. Subsequent treatment of the enriched LMC with acid gave a residual manganese content in the LMC of 1.7% at the initial 17%, which corresponds to the transition of 90% manganese into the solution.

The analyzes showed that the organic content in the LMC is on average 14%. Additional experiments with the addition of manganese dioxide to the ZhMK showed that such an amount of organic matter allows the manganese to be completely restored when its content in the ZhMK is not more than 26%. The maximum content of manganese in the LMC does not exceed 20%, which allows the use of this recovery method for any batches of LMC.

The industrial process can be implemented in a fixed layer in a container with a set of horizontal pipes in which electric heaters are installed or a heating agent passes. Exhaust gases and water vapor prevent air from entering the unit. For cooling, air can be pumped through the same pipes. When used for firing the apparatus with stirring, a rational technique for rapid cooling may be an injection of water.

With high output, standard calciners can be used for firing.

Thus, the present invention allows to simplify the recovery of iron-manganese nodules as much as possible in comparison with any other method and to ensure their cost-effective processing into manganese compounds.

Claims (1)

A method of reducing roasting of iron-manganese nodules, including heating them with a reducing agent to reduce manganese dioxide (MnO ₂ ) to a divalent state (MnO), characterized in that the reducing calcination of iron-manganese nodules of the Baltic Sea containing MnO _{2 is} not more than 26%, using as a reducing agent organic substances contained in their composition in an average amount of 14% when heated to a temperature of 400 ° C with limited air access to the firing zone.