Submerged Arc Furnace Operation

In order to meet the needs of technological progress in the production process of calcium carbide and ferroalloy enterprises, Xi'an Hani introduced the principle of SAF and a series of knowledge of submerged arc furnace operation.

As we all know, the submerged arc furnace is an electro-metallurgical equipment that uses the arc heat at the end of the electrode and the resistance heat of the charge or slag to convert electrical energy into heat energy, so that useful elements such as metals are reduced from ores or oxides. It is mainly used for the reduction and smelting of metal oxide ores, and it is also used in ore reduction electric furnaces. In addition, because most of the arcs of the submerged arc furnace are deeply buried in the charge, it is also called a buried arc furnace.

So what are the issues we need to know and pay attention to when reducing smelting, let's take a look.

Raw materials for the production of high carbon ferrochromium

The raw materials for the production of high carbon ferrochromium are mainly chrome ore, coke and silica. Sometimes in order to adjust the slag type, it is necessary to add a certain amount of white ash (limestone) or dolomite.

The selection of high-quality raw materials (that is, high content of useful elements, good performance, and good particle size) for smelting production is to save energy and reduce consumption, improve the normal operation rate of equipment, keep furnace conditions in good order, and ensure good performance.

Important material conditions for product quality stability.

The basic principle of high carbon ferrochromium smelting

Due to the furnace temperature, high-carbon ferrochromium with high chromium content is mostly produced by flux method in submerged arc furnace.

The so-called submerged arc furnaces method (electric furnace flux method) is that the raw materials are batched in the order of coke, silica and chrome ore, and the mixed raw materials are added into the furnace and around the electrodes by the automatic batching system, or the charge is directly added to the furnace by using a feeding tube. And around the electrode, and maintain a certain height of the material surface, the added material surface should be a large flat-topped cone. The electric furnace uses self-baking electrodes. The three-phase electrodes are deeply buried in the charge, and the charge is heated by the resistance heat generated by the arc heat and the current through the charge, so that the charge is melted and reduced.

The slag and iron are regularly discharged through the tap hole, and new material is added in time with the continuous sinking of the charge to maintain a relatively stable material level.

Lengthen the electrode shell, add electrode paste and press and discharge the electrode in time according to the consumption of the electrode. The entire production process is cyclical and continuous.

Preparation, proportioning & loading of raw materials

1. When all incoming raw materials enter the factory, relevant personnel must notify the laboratory in time for sampling and testing. It is required that laboratory test personnel should provide the most accurate test results in the shortest possible time. Various raw materials of different varieties and different grades must be stacked separately, and mixing is not allowed. All kinds of new raw materials are not allowed to be put into use without testing or permission from the production department supervisor.

2. There should be obvious signs on the stacking places of various raw materials and behind each batching warehouse to indicate the variety and grade of raw materials to prevent mixing.

3. Generally, the raw materials into the furnace should be composed of 2-4 kinds of chrome ore, coke and silica and other raw materials. Sometimes, due to the unreasonable ore mix, it is necessary to add an appropriate amount of limestone (to adjust the slag basicity), dolomite (to adjust the magnesium-aluminum ratio), iron ore (to adjust the ferrochromium grade) and other auxiliary materials to adjust the composition of raw materials, so as to ensure normal production and smelting. Qualified products. It is required that the measurer must accurately weigh according to the provisions of the charge ratio notice.

4. According to the actual situation of the site, in order to better adjust the uniformity of the raw materials entering the furnace, the general requirements:

The 9# silo is loaded back into the charge;

4# silo loaded with silica;

1# silo loading coke: other silo loading is required to be separated by name.

5. Because the accuracy of the ingredients will directly affect the furnace condition and product quality, it is required that the measuring instruments must be standard and accurate, and should be regularly checked by the functional departments according to the usage specifications. Each production team checks the error condition of the scale at least once and adjusts it in time.

6. Because the accuracy of the ingredients will directly affect the furnace condition and product quality, the ingredients operators are required to charge the ingredients according to the proportions specified in the charge ratio notice, and are not allowed to make any adjustments without permission. And truthfully record the material consumption of each furnace and each shift. After receiving the charge ratio change notice, change the batch ratio in a timely manner, and make a record truthfully.

7. After all the equipment used is debugged and normal, it is not allowed to tamper with or change the operating procedures without permission to ensure the accuracy of the charging ratio. General: The maximum batch size required is not

It must be more than 1650kg (chromium ore)/batch and species to ensure that all kinds of charge are mixed as evenly as possible.

Some of the above parameters are based on the data of 30000KVA submerged arc furnace operation. For more consultation on SAF, EAF, LF and other metal melting furnaces, please continue to pay attention to my blog.

If you have any questions or needs, please feel free to contact me at any time.

E-mail: saleswn@hanrm.com / inquiry66@hanmetallurgy.com

Xi'an Hani Tech Co.,Ltd.