Posted 22 Dec 2010 20:47
Steel and iron production process, resulting in the reuse of the solid by-product of steel production plant has become an important issue must be faced. Not only because of increasingly strict environmental requirements, but also because of the shortage of raw materials and other natural resources, leading to a sharp rise in prices caused by increased product costs. PAULWURTH use of blast furnace slag is a slag granulation and processing techniques, cold bonding technology, rotary, multi-chamber furnace roasting and various types of direct melting technology, almost all metallurgical processing residues of professional technology company. Various processing techniques have different advantages and disadvantages, and thus not the same range of applications. This article focuses on Taiwan's steel mills owned PAULWURTH DRAGON residue treatment plant metallurgical production. Alternating steel residue treatment process residues from the recovery of metal oxides, the need for the relevant oxides reduction (usually C as a reducing agent) and melting, in order to separate the metal (except Zn, in general, electrolytic separation .) These two steps can be completed in the same oven can also be different in the two furnaces were completed. In other words, the residues can be added after reduction by the pre-blast furnace, converter or electric arc furnace smelting. Residue handling methods based on the number of different use of the stove can be named, respectively, step and two-step process. A typical step is to restore the product that is pre-blast furnace pellets added; or in an electric furnace, the steel production process has completed the reduction of dust and melting. REDSMELT process is the remnants of pellets made of rotary hearth furnace in the pre-reduction, and then joined the remnants of pre-reduction furnace for melting. This is a typical two-step treatment process. Select a step or two-step Process residues, not only according to residue type, but also consider economic and other aspects. If the residues in the metal content is low, you do not need pre-reduction, enabling selection process one step lower total energy consumption. If treatment of the steel mill residues, the step and two-step process can be selected, but the choice of two-step process with pre-reduction process, can greatly reduce the total energy consumption, enabling lower total conversion costs. Handling arc furnace production of steel dust generated by C, currently the most widely used process is still WAELZKILN. This method recovered most of the Zn, but some residual Zn and ýb and all remain in the slag in the iron. However, if the two-step process using PAULWURTH of PRIMUS steel smelting furnace dust treatment, you can recover all of the Zn, Pb, and most of the Fe. If you are dealing with remnants of the United Steel Company, the best way is to restore the remnants of pre-made pellets or pressed into blocks to join the blast furnace. Currently, the company has completed the pre-reduction and smelting process stage of the two. "Pre-reduction" is not a simple "restore", which means that at this stage of the furnace operating temperature, residence time in the furnace charge and the reduction degree of the metal metal can not be completed. For example, the residue containing Cr Cr reduction, and only at very high temperatures, that is much higher than the furnace temperature is the case, Cr can be restored. For Fe, the only metal to reach or exceed 90% instead of Fe. Study confirmed that although a higher reduction degree of pre-melting stage can reduce energy consumption, but will reduce the pre-reduction furnace productivity. Therefore, we must find an optimal production program to ensure the pre-reduction and melting furnace productivity between the relative balance to achieve. DRAGON electric arc furnace steel mills there is a production and storage of many outstanding electric furnace dust. In addition, a new integrated steel company is redoubling its efforts in the construction. In order to complete including the blast furnace, converter and sintering plants the dust, debris and other residue recycling, DRAGON performance of steel chosen is flexible and can handle mixed residual material PRIMUS technology. This process can be applied to different production conditions: 1) new products per year EAF dust processing or storage of the EAF dust 8500t; 2) 10000t annual processing of EAF dust from 60% and 40% of the converter, consisting of blast furnace dust and mixed dust .