Over the past decade, the domestic steel industry production continues to expand the development space for the refractories industry, but at the same time of steel industrial users change the quality of refractory materials, ordering, payment method has also brought some problems: low bid, refractory manufacturers almost unprofitable; poor quality of the new blast furnace refractories makes frequent accidents; order contract specifications agreed refractory responsibility of the manufacturer, but no binding the missed appointments responsibility of the user of payment; new financial debt The risk of weakening the enthusiasm and creativity of the refractory industry.
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The above question should be how to deal with? Refractory industry had to find a solution from the point of view of technical and operational policy. Such as providing technical service work, the service allows users to understand the key parts of the furnace refractories quality and service life of the relationship. I believe that the blast furnace, hot stove If you want longevity in order to reduce the cost, high-quality refractory materials must be used; refractories for some less demanding requirements for steels of different levels with different grades of refractory to competitive prices, there is no need to finicky performance indicators to meet the requirements can be.
Higher prices for better quality to ensure that the blast furnace performance and promote longevity and stability
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The general large blast furnace life expectancy of 15 years to 20 years, that is longevity. Ensure their longevity premise is to ensure that the quality of the equipment and refractories.
Wuhan Iron and Steel No. 5 blast furnace life of 16 years, with andalusite low creep mullite brick. From the spectrum analysis, the use of fused corundum, sintered corundum, mullite aggregate, and andalusite fine aggregate, with a fine matrix components design makes use of 16 years of brick shrink little change. Similarly low creep brick, and if the price is relatively low, the manufacturers in order to maintain a certain level of profit, may be replaced in the material matching the low-grade materials, in order to reduce costs. Analysis shows that an inferior low creep high alumina bricks, aggregates spent a certain amount of corundum, making the appearance of the corundum particles can be seen after the cutting, but which contain silica, which utilizes part of the expansion of quartz offset brick contraction performance indicators has not changed much, but the results will be affected. Andalusite low creep mullite stone tile order price of 8000 yuan / ton, and now some of the so-called low creep high alumina bricks tender price as low as 4,000 yuan to 5,000 yuan / ton, the projections corundum Bergamo to stone raw materials from raw materials prices have more than 4000 yuan / ton plus brick, firing, inspection and yield of the cost of such a low price is impossible to ensure high quality.
Therefore, I believe, refractories price of the product must be in a reasonable price range. But the question is: on the one hand, the iron and steel enterprises to use the expertise of the refractory performance is not very familiar with, believe that more low-cost and contract indicators in the tender; On the other hand, some of the cut-throat competition in the refractories industry caused by the low bid popular, especially turnkey nature of successful projects, to suppress a part of high-quality products living space.
From longevity point of view, should be combined with the production process of the refractory determine the type and grade of refractory raw materials to produce products, and then focus on the analysis of the products associated with the use of specific performance can be. To ensure product performance, I believe that should be the premise of high-quality products at higher prices, the only way possible to ensure that producers choose the right raw materials and reasonable ratio.
By observing the microporous carbon brick and the of ultrafine mesoporous carbon brick structure shows that the microporous carbon brick can select a block of carbon and silicon metal raw materials, you can choose Electrically Calcined Anthracite, electrode graphite or other badly carbon material as a raw material. It should be noted, is closely related to the microporous or ultramicropore generation and selection of raw materials, a high degree of graphitization of carbon materials, ductile, very dense different raw materials; Si content of more than 96% of the silicon metal powder price reached 12,000 yuan ~ 14,000 yuan / ton, the production of ultrafine porous carbon brick requires high temperature, atmosphere protection, molded under pressure and heat, the right price, it is difficult to select suitable raw materials to ensure product quality. In recent years, part of the blast furnace accident-prone one of the reasons is too much emphasis on the low bid and lead to poor quality of refractory products.
Different parts of the difference between the selection and the overall life balance
Metallurgical furnaces in the iron and steel industry, the use of different parts, subjected to different environments, refractory requirements are also different. If it is not treated differently, may cause serious damage to the local resulting in overall repair or overhaul. Such as blast furnace main gully erosion is the most serious part of it is the slag line and slag dam site. Early main trough castable only one grade, SiC content is 11wt% ~ 13wt% (weight percent). 3200m3 blast furnace main trough a patch through the amount of iron in the 8 million tons to 10 million tons; SiC content of 20 wt% to 30 wt% of the slag line castable wire castable comprehensive masonry, a casting with preformed slag dam 3200m3 blast furnace main trough a patch through the amount of iron can be increased to 12 million tons to 18 million tons. Another example is the pellet rotary kiln with refractory materials, the the cylindrical part Yaotou wear, impact, peel off the most serious, if you use a masonry materials, life of may Yaotou the only 6 months to 8 months, cylinder parts of the life expectancy of two years, therefore, the shortest life parts need to be replaced, it will affect the overall usefulness.
However, compared to the refractory the masonry process and quality improvement, the steel business users are more concerned about the cost and whether it will affect the production process. From the iron trough refractory view: 97% to 98% of the content of silicon carbide price of 5700 yuan to 6600 yuan / ton, dense corundum from 5,000 yuan to 5,500 yuan / ton, plus the cost of a fine powder matrix, high-grade casting material costs may be 5500 yuan to 6500 yuan / ton, used in key parts of high-grade materials, with the use of suitable refractory materials, refractory manufacturers can guarantee profitable in the general area, and help to achieve economies of steel mills procurement. In fact, blast furnace iron trough of refractory material changes precisely because tons of iron sourcing arrangements result of technological progress (tons of iron contracting consumption of one ton of iron refractory, prompting Refractories supplier active in quality assurance with reasonable under the circumstances). Large pellet rotary kiln current overhaul life is 2 years, if the implementation ton ball refractory consumption contracting, the castable Yaotou possible to realize the higher prices for better quality, comprehensive masonry refractory sub-parts and maintenance, reached three years the overhaul life to 5 years is possible.
In refractory technology development process, once firing at high temperature, high purity raw materials, high pressure forming as a technology development direction. With increasing cost pressures, refractory manufacturers to increase the low level of raw materials, research and utilization of recycled materials, but from the point of view of the scene, the harsh conditions of use must put forward higher requirements on the material. Therefore, using different grades of material integrated masonry, composite use to achieve the best life balance is the direction of the pursuit of the refractories technology. Firing at high temperature, high purity raw materials, hydroforming can get excellent performance, it can be used in key parts of the overall cost can still be reduced. Such as use of the sliding plate brick high temperature sintered zirconia inner ring is a typical example, expensive zirconia material to resist erosion damage of the molten steel, and other composite materials as the slider body material, an increase in the frequency of use, decreased overall costs.
Provide the appropriate use of space for the different grades of material
With the the refractories industry s profit margins gradually narrowing, manufacturers began to seek alternative raw materials starting from the raw material point of view, to reduce costs as much as possible. The typical case is to steelmaking tundish paint.
Tundish coating if the price of 1,800 yuan to 2,000 yuan / ton, MT-2 ~ MT-4 standard paint MgO content of 90% to 97% of the magnesia prices from 950 to 1700 yuan / ton, the production enterprises meager profits; price to 1,500 yuan / ton or less unprofitable. For this reason, many manufacturers using the price of only 450 yuan to 500 yuan / ton forsterite partial substitution of raw materials to produce forsterite coating, using the results meet the requirements. High MgO content standard assessment, the product failed, such as coatings MT-1, MT-5, the indicators, forsterite coating may meet the compositional requirements.
The key problem is that the the magnesia coating may affect the quality of certain types of steel. For example, studies have shown that: with respect to magnesia spray paint and covered with low alkalinity agent, magnesium calcium spray paint and high calcium covering agent, molten steel ≥ 5μm inclusion removal rate by 82.2% to 83.4%, ≥ 0.55 μm inclusion removal rate from 79.1% to 83.0%; can reduce the the steel total oxygen content of 8% to 14%, reduce 8% to 16% of the total nitrogen content of the molten steel. However, for the majority of users, the forsterite coating can still meet its requirements.
Thus, suitable refractory materials under different conditions of use should be encouraged, in order to expand the use of different grades of refractory space. Refractory technology, the development of an iterative process, such as dolomite lining – carbonaceous lining – carbon-bag lining the process of change; Similarly, the iron and steel industry there are also some technical repeated, such as the use of active lime steelmaking slag forming Now, in order to reduce the cost of steel making, a small number of steel mills with limestone slagging also achieved success. Refractory practitioners only to track the user s requirements, and carry out technological change, will it be possible to meet user requirements at the lowest cost.
Judging from the analysis of the blast furnace low creep high alumina bricks, coal briquettes, pellets rotary kiln castable, etc.: to ensure a reasonable purchase price of manufacturing enterprises to be possible to select high-quality raw materials to ensure product quality. For refractory practitioners must communicate with the iron and steel enterprises to use cost-effective technologies and products to ensure the longevity of the blast furnace system stable. Less long-lived high-temperature devices such as the trough of blast furnace, rotary kiln, using high-quality materials in key positions, meeting the needs of the harsh conditions of use, can be integrated by using different grades of materials masonry compound used to achieve the best balance of Life, to reduce costs, reduce the time spent.
The author believes that the unlimited low refractory purchase price will ultimately harm the development of the iron and steel industry. Tons of iron per ton of steel, tons ball refractory consumption which gives the suitable refractory Price conducive to technological progress refractories, but also conducive to the steel mills in the case to ensure the performance and quality more economical procurement costs. In the iron and steel industry profit margins generally lower under the premise of the refractories industry must also take the initiative to improve the technical content changed the way business, money to pay for the goods, technology UNPROFOR, improve service quality, etc., to ensure smooth production of steel users, and ultimately achieve mutual benefit and win-win results.