Ferroalloy furnace's introduction

What is ferroalloy furnace?

Main equipment for smelting ferroalloy. Ferroalloy electric furnaces are divided into reduction electric furnaces and refining electric furnaces. There are various types of electric furnace, such as electric furnace with open or semi arc operation, or electric furnace with submerged arc operation. Electric refining furnace is used to refine medium carbon, low carbon and micro carbon ferroalloys. The capacity of electric furnace is generally 1500 ~ 6000 KVA, which adopts the form of open fixing or tilting with cover. The former is similar to the reduction furnace and can be equipped with continuous self baking electrode; The latter is similar to electric arc steelmaking furnace, using graphite or carbon electrode.

Ferroalloy furnace's classification

Reduction furnace

Also known as submerged arc furnace or submerged arc furnace, the open fixed electric furnace is adopted when the electrode is inserted into the charge. With the improvement of environmental protection requirements and the progress of waste heat utilization technology, closed electric furnace, low smoke hood and semi closed electric furnace are adopted for different products. The rotation of the furnace body can eliminate the hanging material, reduce the "pricking fire" of crusts, make the distribution uniform and expand the reaction zone, so as to facilitate the smooth operation of the furnace. The capacity of electric furnace (in ferroalloy production, it refers to the capacity of electric furnace transformer, according to KVA, which is used to mark the capacity of electric furnace) generally changed from hundreds to 10000 KVA before the 1950s, and then gradually developed to large-scale. In the 1970s, the newly-built electric furnace was generally 20000 ~ 40000 KVA, the largest closed electric furnace was 75000 KVA, and the largest semi closed furnace was 96000 kVA.

Modern ferroalloy electric furnace is generally a circular furnace body, equipped with three electrodes. Large scale ferromanganese electric furnace has the advantage of using rectangular multi electrode. Some large ferrosilicon electric furnaces are equipped with rotating mechanisms. The furnace body rotates or swings back and forth in the horizontal direction at the speed of 360 ° rotation in 30 ~ 180 hours. The closed electric furnace is provided with a sealed furnace cover, and the semi closed electric furnace is provided with an operation door with adjustable opening under the smoke hood to control the amount of air drawn in and the temperature of flue gas.

Continuous self baking electrodes are widely used in electrode systems, with a maximum diameter of 2000 mm, and some are made into hollow ones. The continuous self baking electrode is composed of a thin steel plate electrode shell and an electrode paste. During operation, the electrode paste is baked by itself using the heat generated when the current passes through and the conduction radiation of furnace heat. With the consumption of electrode, the electrode shell shall be welded section by section and filled with electrode paste. The electrode holder is composed of contact cheek plate (conductive copper tile), copper tube, holding ring and other components. Its function is to transmit current to the electrode, clamp the electrode at a certain height, and adjust the sintering state of electrode paste. The electrode lifting and pressing device suspends the whole electrode to adjust the insertion depth of the electrode.

The feeder line from the low-voltage side of the transformer to the electrode holder is commonly known as short network. It is a section of conductor with large cross-section, which is used to transport large current to the furnace. Most of the secondary windings of large electric furnace transformers complete triangular wiring on the electrodes through short nets. The whole network is composed of hard bus harness, soft bus harness and copper pipe.

Refining electric furnace

Used for refining medium carbon, low carbon and micro carbon ferroalloys. The capacity of electric furnace is generally 1500 ~ 6000 KVA, which adopts the form of open fixing or tilting with cover. The former is similar to the reduction furnace and can be equipped with continuous self baking electrode; The latter is similar to electric arc steelmaking furnace, using graphite or carbon electrode.