Production of wear-resistant ceramics for the overflow elbow of cyclones
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The wear-resistant ceramics used in the overflow elbow of cyclones: Cyclones are widely used wet separation and classification machinery, serving as devices for separating solid-liquid mixtures. They are primarily employed for tasks such as liquid clarification, slurry concentration, washing of solid particles, sorting and classification of solid particles, and removal of sand from liquids. To date, it has been widely applied in sectors such as mineral processing, chemicals, petroleum, light industry, environmental protection, and mining. The overflow elbow of cyclones often wears out, which affects their service life. The company has developed wear-resistant ceramic overflow elbows for cyclones; these have excellent wear resistance and can be used for a long time. The overflow structure of the hydrocyclone consists of a hydrocyclone, a rectangular-section involute volute, and a throat section. It is characterized in that the upper end of the throat section is vertically inserted into the center of the rectangular-section involute volute and welded to it, while the lower end of the throat section is connected to the overflow pipe of the hydrocyclone via flanges. The overflow elbow consists of a straight section, an 180-degree bend, and flanges. Due to the high impact forces involved, it is manufactured using a ceramic composite process with release force properties; this ensures that the wear-resistant layer becomes integral to the steel pipe, preventing the ceramic from coming off. The steel pipes are standard seamless pipes as per national specifications, with the bending radius being kept within reasonable limits. The modified overflow elbow is easy to install and remove, as well as convenient for replacement.
Advantages of ceramic wear-resistant elbows: The self-propagating ceramic composite elbow is a type of composite pipe manufactured using the \"self-propagating high-temperature synthesis high-speed centrifugation technology,\" which results in the formation of a uniform, dense, and smooth ceramic layer as well as a transition layer at high temperatures and high speeds. Ceramics do not fall off at high temperatures, and they are relatively light in weight; composite ceramics possess high hardness and good wear resistance. Self-igniting ceramic straight pipes, wear-resistant elbows, ceramic tees, etc. have found extensive use in industries subject to severe wear, especially in dust removal and ash conveying pipelines, where they deliver significant benefits. Disadvantages of ceramic wear-resistant elbows: Ceramic wear-resistant elbows are not resistant to impacts; they are not suitable for use with large-grained ores. Elbows made of ceramic materials should be used in pipelines under high pressure as well as in slag removal pipelines.
Ceramic-lined composite steel pipes: Ceramic-lined composite pipes possess advantages such as high strength, good toughness, impact resistance, excellent weldability, high hardness, good wear resistance, corrosion resistance, and heat resistance. They overcome the limitations of corundum ceramics, including low hardness, poor wear resistance, and weak toughness. Therefore, composite pipes possess good wear resistance, heat resistance, corrosion resistance, mechanical impact resistance, and thermal shock resistance, as well as excellent weldability. It is often used in wear-resistant and corrosion-resistant pipes for transporting granular materials, as well as in applications involving grinding and corrosive media. The advantages include the ability to weld directly, relatively low cost, and improved overall wear resistance of the pipes.
Technical specifications for wear-resistant ceramic elbow pipes: 1. Wear-resistant ceramic elbows are primarily used to protect pipes from damage caused by the abrasive action of mixed gas streams, to prevent leaks resulting from such wear and thus avoid environmental contamination, and to extend the service life of the pipes as much as possible. 2. The design, manufacturing, and acceptance of wear-resistant ceramic elbows and wear-resistant ceramic straight pipes are carried out in accordance with current international and domestic codes and standards. Ceramic-lined wear-resistant elbow pipes should be designed and manufactured in accordance with the YB/T 176-2000 standard. 3. The interface dimensions, external dimensions, flow cross-section, and other design parameters of the wear-resistant ceramic elbow shall meet the requirements ； It provides good connection to pipes or other equipment, with excellent sealing properties. For all weld seams between the wear-resistant elbow pipes and wear-resistant ceramic straight pipes, ceramic sheets are applied on the inner walls using the same process in the field; the ceramic should be flat and form a smooth surface. The diameter and material of the straight section of the wear-resistant elbow should be selected to facilitate welding with the powder supply pipeline. The appearance of wear-resistant elbow pipes should be smooth, free from defects such as blemishes or oxide layers. The inner surface of the wear-resistant elbow shall be free from casting defects such as shrink holes, porosity, and sand holes. Design of drawings for wear-resistant ceramic elbow pipes: 4. The wear-resistant ceramic elbow pipes, along with the corresponding straight pipe sections at the front and back (denoted as L and K in the table), should be delivered as a complete unit, allowing for direct installation on site without the need for prior assembly. In the table, the length of the straight sections L and K of the elbow that are not in contact with ceramic at their connections to the straight sections of the coal powder pipeline shall not exceed 100 mm. 5. Depending on the working environment, the wear-resistant ceramic elbow lining is made of alumina ceramic sheets with a purity of 95%, and its designed thickness is 8 mm; the elbow is constructed from 20# steel, with a designed thickness of 10 mm. The alumina ceramic used (with a purity of 95%) features a high green density, uniform density distribution, a dense crystal structure, as well as excellent mechanical properties and wear resistance. 6. The slag on the cross-section or edges of the steel parts to be welded after thermal cutting must be removed.