I. Construction methods
1. Wet masonry
For anti-stripping high alumina bricks, silica-molybdenum bricks, silica-molybdenum red bricks, etc., wet masonry is generally used. During wet masonry, the following matters must be noted:
(1) Refractory bricks require full mortar in the masonry joints, and the width of the brick joints should meet the design requirements of the drawings.
(2) After each refractory fire brick is placed, it must be knocked with a wooden hammer or rubber hammer to squeeze out excess fire mud. It is necessary to ensure that the brick joints are completely close to the shell, and the fire bricks should be in surface contact and firmly bonded. When knocking refractories bricks, inappropriate knocking or squeezing should be prevented from damaging the refractory firebricks or damaging the fire mud that has begun to solidify.
(3) Before the fire mud in the brick joints is completely hardened, the excess fire mud should be scraped off. If there are places that need to be filled with fire mud, a scraper should be used to fill the new fire mud, that is, the masonry joints.
(4) The mortar joints should be horizontal and vertical, the arc surface should be flat, and the joints should be tight. The masonry should be consistent with the dimensions indicated by each equipment.
(5) Straight walls should be built with staggered joints, and arches and kilns should be built with straight through joints in the circumferential ring direction. The masonry should strive to have straight brick joints and smooth arc surfaces. The geometric shape of the masonry should meet the requirements of the drawings to ensure quality.
(6) From construction to production, the masonry should be protected from moisture and freezing, and from excessive temperatures that occur too early, so that the refractory mud cannot reach the required strength.
2. Dry masonry
Dry masonry is generally suitable for magnesia refractory brick systems, such as straight magnesia bricks, magnesia-alumina spinel bricks and magnesia-iron spinel bricks. The requirements for arch ring fire bricks built by dry masonry are similar to those of wet masonry. Finally, they should be wedged with a 2mm thick steel plate. The steel plate should be flat, without bumps, burrs, or rust. The head should be ground with a wedge angle of less than 60 by a grinding wheel to facilitate wedging. Only one steel plate can be wedged into a brick joint, and two steel plates are prohibited from being wedged into a brick joint. The steel plate should not be wedged into the brick joint of the lock-joint brick, and 1 to 2 brick joints should be separated.
2. Construction
First, before laying the lining, the convexity of the weld in the kiln shell should be carefully checked to see if it meets the welding technical requirements of the kiln shell. For welds that exceed the specified limit, a portable grinding wheel should be used for grinding. Before laying, the rotary kiln should be thoroughly cleaned, kept clean and dry, and free of ash, rust, oil and water. Metal rust must be removed with a wire brush. Ensure a good combination between the refractory bricks and the kiln shell.
Secondly, the refractories bricks of the rotary kiln must be laid out before laying, and the masonry must be checked and inspected in stages based on the precise positioning line. The axial reference line of the rotary kiln is about 1.5m long along the circumference, and the axial direction must be parallel to the axis of the rotary kiln. The rotary kiln has an annular reference line every 10m and an annular control line every 1m. The planes formed by the closed annular lines should be parallel to each other and perpendicular to the axis of the rotary kiln. These positioning lines will be the standard for routine inspection during the masonry process. Multiple inspections, timely adjustments and corrections will effectively prevent the accumulation of large deviations during the masonry process. The laying out of the axis of the rotary kiln should be carried out by professional surveyors, using approved measuring instruments for measurement and laying out. The rotary kiln can only be laid on the premise that the rotary kiln cylinder is clean and dry, truly free of dust, rust, oil and water, and the positioning lines are accurate and correct.
