The invention belongs to the field of iron and steel metallurgy and relates to achromium carbideOr the preparation method of chromium nitride. Chromium carbide or chromium nitride is widely used as superhard materials, steel-making additives, wear-resistant materials, corrosion-resistant materials, catalysts, etc. Chromium nitride is an antiferromagnetic material, because of its high hardness, good resistance to acid and alkali corrosion, high chemical stability, good wear resistance, high melting point, is widely used in magnetic, electronic industry, high temperature resistant structural ceramics and other fields. The existing chromium carbide or chromium nitride production process is complicated, the equipment capacity is low, the heat transfer efficiency is low, the energy consumption is high, and the reaction process is easy to harden, resulting in difficulty in discharging.

The purpose of the invention is to provide a low energy consumption, large equipment capacity, good product quality consistency, stable process.chromium carbideor chromium nitride production process. The chromium raw material and/or the carbonaceous reducing agent or the solid material (hereinafter referred to as the material) produced in the reaction process is directly energized by the power supply electrode in the direct heating type rotary kiln, and the material is heated by heating under the action of the electric current according to the electric resistance of the material itself or the contact resistance between the raw material particles or blocks.

The purpose of the present invention is achieved as follows: a preparationchromium carbideOr the method of chromium nitride, especially the industrial preparation method, includes the following steps: mixing chromium raw materials and carbonaceous reducing agents to form solid raw materials, and then sending the solid raw materials into a reaction furnace for heating, wherein the chromium raw materials are reduced in a reducing atmosphere The carbonitriding process synthesizes chromium carbide or chromium nitride; the chromium carbide reaction furnace is an electric heating rotary kiln (hereinafter referred to as a direct heating rotary kiln) with a heating section in the furnace, the heating section is provided with a heating power electrode, through which a voltage is applied to the heated material, thereby conveying current to the heated material, and the heated material is heated by the resistance of the heated material accumulated in the heating section; the heating process is as follows: chromium carbide is in the heating section of the direct heating rotary kiln, solid raw materials and/or materials changed in the heating process (hereinafter referred to as materials) are directly energized through power supply electrodes, and the materials are heated in the heating section through their own resistance or the contact resistance between material particles or blocks; the materials are discharged after preheating, heating and cooling in the direct heating rotary kiln; the temperature of the materials passing through the direct heating rotary kiln is not lower than 750; the solid raw material is mixed with chromium raw material and carbonaceous reducing agent, rolled or extruded, ball milled, wet milled and/or briquette before entering the direct heating rotary kiln;chromium carbideThe reducing carbonitriding process is carried out in a reducing atmosphere of less than 5mpa. The reducing atmosphere is one or a mixture of methanol, nitrogen, ammonia, hydrocarbon and other gaseous organic matter containing carbon and/or nitrogen, or the reducing atmosphere is generated by reducing the oxygen-containing chromium raw material by a carbon-containing reducing agent; the carbonaceous reducing agent is one or a mixture of graphite, carbon black, activated carbon, coke, petroleum coke, asphalt, starch, cellulose, organic polymer, melamine, paraffin and sugar; the reduction carbon-nitrogen co-penetration process is: at 300-1900, the material is reduced and carbonized by carbon-containing reducing agents and/or hydrogen and/or carbon-containing reducing agents and/or nitrided by nitrogen elements in the reducing atmosphere, and the high temperature of the material is not less than 750; the finished product of chromium carbide or chromium nitride contains chromium, carbon and/or nitrogen, small amounts of unreacted oxygen and impurities from the raw materials.

The material is directly energized with a voltage of 10-2000 volts and a current of 10-100000 amperes. A chromium carbide preheating section is arranged before the heating section of the reaction furnace and/or a cooling section is arranged after the heating section to preheat and/or cool the material. In the reductive carbonitriding process, the carbonaceous reductant is mixed with the chromium feedstock before the feedstock enters the direct heat rotary kiln. Chromium carbide reduction The carbonaceous reductant in the carbonitriding process is produced by further carbonization of the organic matter in the reducing atmosphere and/or carbonaceous reductant during the temperature rise. One or more of iron and iron oxide (calculated as iron) is added to the solid raw material in an amount not exceeding 5 times the weight of chromium to form a ferrochrome carbide or ferrochrome nitride alloy.

Compared with the prior art, the present invention avoids disorderly heating of refractory materials and furnace body materials, has high heat utilization rate and low power consumption. and avoidedchromium carbideThe thickness limitation of the thin material pile brought by the heat transfer requirement improves the utilization rate and productivity of the furnace space, and also makes the direct heating rotary kiln device smaller. Therefore, it is easier to heat the material to the reaction temperature, the reaction speed is faster, the reaction time is shortened, the oxygen content of the product is low, the free carbon of the product is low, and the high quality chromium carbide product can be obtained. The heat and mass transfer process in the reaction process are further improved, the material can move continuously in the direct heating rotary kiln, which is convenient for large-scale industrial production and has good product consistency. More importantly, with the rotation of the direct heating rotary kiln, the material is constantly turned over, which avoids the hardening and agglomeration of the material in the reaction process, and enables the production to be carried out continuously, reliably and stably for a long time. The intermittent operation in the process of electric arc furnace, medium frequency furnace and high temperature self-propagating combustion synthesis is avoided, it avoids the heating and cooling process of the kiln body during mass production, saves a lot of energy consumption and time, and reduces the complexity of operation; chromium raw materials such as chromium hydroxide carbide or even ammonium chromate can be used, and the cost is greatly reduced.