Process and device for carbon-free roasting of molybdenum concentrate in multi-hearth furnace

Abstract

The invention discloses a process and a device for carbon-free roasting of molybdenum concentrate in a multi-hearth furnace, and the process comprises: high-temperature flue gas generated during roasting in a multi-hearth furnace is subject to heat exchange with air in a surface cooler, and the high-temperature air is discharged from an air outlet of the surface cooler; the high-temperature air is separated into two parts with one part discharged into the atmosphere and the other part discharged into main air supply pipelines disposed at the left and the right sides of the multi-hearth furnace hearths; the high-temperature air in the main air supply pipelines enters each layer of the multi-hearth furnace through a plurality of branch pipelines disposed on the main air supply pipelines, and oxygen is fully reacted with molybdenum concentrate to generate molybdenum trioxide. The device comprises the multi-hearth furnace, and the surface cooler connected with flue gas collecting pipelines of the multi-hearth furnace; the air outlet of the surface cooler is partitioned into two paths with one path communicated with the atmosphere through a first pipeline and an evacuation valve and the other path connected with the main air supply pipelines through a second pipeline and an air-guiding valve; the plurality of branch pipelines disposed on the main air supply pipelines are connected with air inlets disposed on the outer wall of the multi-hearth furnace. The invention saves energy, reduces consumption, and realizes carbon-free roasting.

Description

technical field [0001] The invention belongs to the technical field of nonferrous metal metallurgy, and in particular relates to a multi-hearth furnace carbon-free roasting molybdenum concentrate process and device. Background technique [0002] Molybdenum is a chalcophilic element, molybdenite (MoS 2 ) is the main occurrence state of molybdenum. At present, about 96% of all molybdenum concentrates used at home and abroad are converted into molybdenum oxide sand by roasting, that is, industrial molybdenum oxide. Industrial molybdenum oxide reacts with ammonia water to obtain ammonium molybdate, and high-purity molybdenum oxide can be obtained by roasting or sublimation method, and hydrogen reduction is continued to obtain molybdenum metal powder with a purity of 99.98%. [0003] The existing molybdenum concentrate roasting process mainly includes reverberatory furnace roasting process, rotary kiln roasting process, multi-hearth furnace roasting process and fluidized furnac...

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Problems solved by technology

[0005] In the process of roasting molybdenum concentrates in multi-hearth furnaces, natural gas heating requires combustion-supporting air, and the oxidation and desulfurization of molybdenum concentrates requires a large amount of oxygen-enriched air. The existing multi-hearth furnace roasting process is to send normal temperature air directly into the multi-hearth furnace furnace Internally, it is easy to cause hardening of the hearth charge, which will cause the wear of the rake teeth of the rake arms equipped on the central stirring shaft of the multi-hearth furnace, and increase maintenance costs; normal temperature air enters the furnace from the air inlets on each layer of the multi-hearth furnace , the molybdenum concentrate will be lost by the air inlet, which will affect the recovery rate of molybdenum concentrate roasting

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