INVESTIGATION INTO CONDITIONS OF TITANIUM-NIOBIUM CARBIDE CHLORINATION

Journal Article · Fri Jan 01 04:00:00 EST 1960 · Izvest. Vysshikh Ucheb. Zavedenij, Tsvetnaya Met.

OSTI ID:4008511

Meyerson, G A; Zelikman, A N; Belyavaskaya, L V; Tseytina, N Ya; Kirillova, G F

Chlorination kinetics of complex carbide was investigated using a horizontal quartz tube at 800, 600, and 400 deg C and 9 l/min chlorine feed. It was found that chlorination of compact carbide specimens was accompanied by the formation of an external graphite layer. At 400 deg C the effect of this layer on the chlorination rate was not noticeable (the process having a kinetic nature). At 600 deg and, in particular, at 800 deg C, some diffusion inhibition of the reaction was observed due to the graphite layer formed. The nature of the chlorination process becomes intermediate between kinetic and diffusion one, the former being prevalent. The dependence of the chlorination depth on the duration of the process was revealed and used to calculate the maximum possible duration of chlorination of various-size carbide particles at 400, 600, and 800 deg C. The operating chamber of the furnace represents a vertical graphite cylindrical tube with an expanding top pressed into a metallic housing with external heat insulation. A graphite grid is mounted in the chamber bottom. Carbide feed is performed with the aid of a screw feeder. Chlorination process can be conducted at levels of 280 to 420 mm due to the arrangement of discharge pipes at different heights. The furnace is heated with a digitate quartz heater having two heating zones. Chlorides are collected with the use of a condensation system developed by Giredmet. During the chlorination process the graphite accumulates in the bed, concentrates on its surface, and is partially eliminated by the gas flow. To bind the carbon and eliminate it in a gaseous state, preliminary tests of carbide . chlorination were made with a chlorine-oxygen mixture to form CO or CO/sub 2/. The rate of chlorine feed was 2.8 cm/sec for carbide of -- 100 mu - 89%. After the onset of reaction at 200 deg C, the temperature in the bed raised spontaneously and the lower heater was automatically switched off. The top heater was switched off at 450 deg C. When operating with a chlorine--oxygen mixture, the latter was supplied to the furnace at 600 deg C. At the beginning of the experimental investigation carbide was supplied to the furnace periodically through a funnel and later on continuously by the screw feeder. Preheated carbide of the following composition was used: 52.40% Ti; 8.85% Nb; 4.67% Si; 0.24% Fe; 0.07% Ca; 12.17% C/sub bou//sub nd/; 11.10% C/sub fre//sub e/; 2.90% N; an d 7.60% 0. The experiments proved the possibility of continuous powder carbide chlorination in a fluidized bed with chlorine or a . chlorine-- oxygen mixture. The main advantage of the latter method is the elimination of C in the form of CO or CO/sub 2/. The process can be conducted in a fluidized bed on account of the reaction heat without an external heat supply even in a smsll-scale furnace (0.0177 m/sup 2/ floor surface). Fluidizedbed chlorination is characterized by a high output (300 kg/hr per m/sup 2/ of furnace floor), a high degree of utilization of raw materials (98--99 and a fairly high purity of the products obtained. These values exceed considerably the efficiency of direct chlorination of ore concentrates in the form of briquets mixed with coal. (OTS)

• Research Organization: Krasnoyarsk Inst. of Non-Ferrous Metals, USSR
• NSA Number: NSA-15-026027
• OSTI ID: 4008511
• Journal Information: Izvest. Vysshikh Ucheb. Zavedenij, Tsvetnaya Met., Journal Name: Izvest. Vysshikh Ucheb. Zavedenij, Tsvetnaya Met. Vol. Vol: No. 5
• Country of Publication: Country unknown/Code not available
• Language: Russian

Related Subjects

CALCIUM
CARBON
CARBON DIOXIDE
CARBON MONOXIDE
CHEMISTRY
CHLORIDES
CHLORINATION
CHLORINE
COMPLEXES
DIFFUSION
EFFICIENCY
FLUIDIZATION
FURNACES
GAS FLOW
GRAPHITE
IRON
LIQUEFYING
NIOBIUM CARBIDES
NITROGEN
OXYGEN
POWDERS
QUARTZ
SILICON
SURFACES
TEMPERATURE
TITANIUM CARBIDES
TUBES