Meishan Equipment Company, upon receiving the commission from Mei Steel Ironworks, promptly assembled a team of technical experts to develop a comprehensive construction plan. The plan included selecting suitable opening and grouting equipment, as well as defining detailed construction methods. The company decided to utilize each blast furnace's off-wind period for high-pressure grouting operations. During each planned off-wind period, the team adjusted the airflow at the furnace edges based on actual conditions and used an infrared thermometer to measure the furnace temperature. They identified areas with higher skin or cooling wall temperatures—indicating the weakest points in the lining—and determined the number of grouting holes and the amount of material to be injected according to the erosion status of the lining.
The construction method involved using a specialized grouting pump manufactured in Japan, designed for blast furnace maintenance and carbon material injection. This pump features a squeezing mechanism, with an output pressure of 3.0 MPa, a flow rate of 30 L/min, and a motor power of 5.5 kW. It operates within a temperature range of 90–110°C. Before starting the operation, the grouting machine was transported to the site for maintenance and electrical testing. Holes were prepared by cleaning and cutting them according to temperature readings taken with an infrared thermometer before each off-wind period. A marking was made at the selected location on the furnace hearth.
A new mechanical drilling method was employed for hole creation. A German-made DN450 drill, capable of creating 304mm-diameter holes up to 300–400mm deep, was used directly on the furnace shell. In cases where mechanical drilling was not feasible, an artificial method was applied. A cutting knife was used to create a 30–40mm hole, followed by drilling with a percussion drill. For existing grouting holes, the old grouting pipe was cut short and then drilled to a depth of 300–400mm using a percussion drill, after which the hole was cleared.
After drilling, the hole was cleaned using a percussion drill. If red coke was observed during the cleaning process, the operation continued until the hole depth exceeded 400 mm, at which point it was stopped. Once the hole was clean, the grouting short tube was welded back in place, a stop valve was installed, and the grouting machine was connected via the shaft joint. Welding the grouting pipe while cleaning the hole was strictly prohibited. The stirring mixer was operated for 5–10 minutes. After confirming that all working conditions were normal, the slurry powder and binder were mixed at a slow speed of 4:1, poured into the mixer, and stirred for 6–10 minutes. Adjustments were made depending on mixing quality, including increasing mixing time and adding more binder to reduce slurry concentration and prevent clogging during grouting, before pouring the mixture into the hopper of the squeezing machine.
Although grouting technology is widely used in construction engineering, its application in the metallurgical industry, particularly for blast furnace linings, remains limited. However, this technology has become an essential part of daily maintenance for extending blast furnace life. At Meishan Iron & Steel Works, the successful implementation of this technique in Blast Furnaces No. 1 and No. 3 improved gas utilization, reduced fuel consumption, increased smelting intensity, ensured stable long-term operation, and achieved high output, good quality, low consumption, and extended lifespan. The non-slurry lining used in high-pressure injection is a non-rigid material. Due to the pressure limitations of the grouting machine, the actual slurry concentration could not meet the supplier’s technical requirements, so the slurry was diluted to complete the grouting task. High-pressure injection grouting pumps can be used for better results.
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