Various valves used in the mineral processing, crushing, conveying, and dewatering links of mines (such as slurry gate valves, flotation feed valves, tailings discharge valves, etc.) are high-frequency fault points in equipment operation and maintenance. Replacing traditional wear-resistant parts requires the overall disassembly of valves and pipelines, with a single maintenance taking 2 to 6 hours, accompanied by losses from shutdown and production reduction. The disassembly-free wear-resistant parts for mine valves adopt a quick-install structural design, enabling on-line replacement of worn components and greatly reducing maintenance time. However, wear-resistant parts made of different materials have significant differences in adaptability, service life, and maintenance efficiency.

Application and Maintenance Characteristics of Rubber Fittings in Removable-Free Mining Valve Wear Parts

Rubber-based wear-resistant parts use natural rubber or nitrile rubber as the base material, which are vulcanized and formed into liners or seals. They are suitable for mining working conditions with mild abrasion and no strong impact, such as the fine particle material conveying scenarios like the feed valves of flotation machines and discharge valves of belt conveyors. These accessories have good elastic sealing performance, which can effectively avoid slurry leakage, and their conventional service life is about 3 to 6 months. The disassembly-free rubber accessories adopt a buckle-type quick-install structure. There is no need to disassemble the valve main body, and the replacement can be completed only by opening the side maintenance port. The single maintenance time is only 15 to 30 minutes, which reduces the maintenance time by 70% to 80% compared with the traditional disassembly and replacement method. The feed valve of a certain iron ore flotation workshop originally used welded rubber liners, and each replacement required disassembling the flange and cleaning the adhesive layer of the old liner, taking about 3 hours for a single time. After switching to the buckle-type disassembly-free rubber liner, the replacement can be completed in only 15 minutes, and the sealing performance is not reduced. However, the wear resistance of rubber accessories is limited; they cannot withstand the scratching of sharp-edged ores and the abrasion of high-concentration coarse particles. They are only applicable to working conditions with an abrasion level of ≤2 grade. Moreover, long-term exposure to high-temperature slurry (＞60℃) is prone to aging and cracking, so they are not suitable for high-temperature slurry conveying valves.

Application and Maintenance Characteristics of Removable Cast Alloy Parts in Removable Mining Valves

Compared with the application limitations of rubber accessories, cast alloy accessories perform more prominently under severe abrasive working conditions and are also suitable for the maintenance needs of disassembly-free mine valves. Cast alloy accessories mainly include two types: high manganese steel and high chromium cast iron. The Rockwell hardness of high chromium cast iron accessories can reach HRC58-62, and their wear resistance is 1.5 to 2 times that of ordinary high manganese steel. They are suitable for severe abrasive working conditions with coarse particles, such as ball mill slag discharge valves and cone crusher feed valves. Disassembly-free cast alloy accessories adopt a modular insert design, which is fixed on the inner wall of the valve by bolt buckles. During online replacement, there is no need to dismantle the pipeline and the valve body. Only the fixing bolts need to be loosened to take out the worn insert and replace it with a new one, and a single maintenance takes 30 to 60 minutes. The ball mill slag discharge valve of a copper ore concentrator originally used an integrated high manganese steel liner, which required 5 hours of shutdown for each replacement and was replaced once a month. After switching to disassembly-free high chromium cast iron inserts, the replacement time of a single insert is only 40 minutes, and the service life of the insert can reach 12 to 18 months, which is 2 times higher than that of the integrated liner. However, cast alloy accessories are relatively heavy, and a single insert can weigh 10 to 20 kg, requiring the use of small hoisting tools for replacement. Moreover, high chromium cast iron has high brittleness, and it is prone to cracking and chipping when impacted by large ore blocks, so it needs to be used with a protective grille.

Application and Maintenance Characteristics of Polyurethane Accessories in Quick-Dismountable Mining Valves

Polyurethane wear-resistant parts are made through polymerization reactions, boasting excellent wear resistance and elasticity. Their wear resistance is 2-3 times that of ordinary high-manganese steel, and they also feature good corrosion resistance, making them suitable for abrasive working conditions with mild corrosion, such as flotation concentrate conveying valves and dewatering screen discharge valves. The tool-free detachable polyurethane accessories adopt an embedded quick-install structure, requiring no bonding or hot installation. Only prefabricated polyurethane liners need to be aligned with the clamping grooves for fixation, with a single maintenance taking 20-40 minutes. Such accessories weigh only 1/5 of cast alloys of the same volume, and a single person can complete the replacement, significantly reducing labor costs. For the discharge valves of dewatering screens in a tailings conveying plant, the original rubber liners only lasted 2 months, and each replacement required disassembling the valve flanges, taking about 2 hours per time. After switching to tool-free detachable polyurethane liners, the service life was extended to 8-10 months, a single maintenance took only 30 minutes, and the annual shutdown loss was reduced by approximately 70%. However, polyurethane materials have poor high-temperature resistance: they will soften and degrade in a long-term pulp environment above 80℃, and cannot withstand strong impact loads exceeding 100MPa, making them unsuitable for valves in high-temperature and strong impact working conditions.

Application and Maintenance Characteristics of Wear-Resistant Ceramic Parts in Disassembly-Free Mining Valves

Wear-resistant ceramic accessories take alumina ceramic as the main base material, with a Rockwell hardness of over HRA88 and wear resistance 2 to 3 times that of high-chromium cast iron. They are the top wear-resistant material for highly abrasive working conditions in mines at present, and are suitable for high-load working conditions such as the feed valves of dense medium cyclones and the slag discharge valves of tailings concentrators. The disassembly-free ceramic accessories adopt a double fixing structure of bonding + snap-fit. When replacing online, there is no need to remove the valve body; only the adhesive layer of the old ceramic block needs to be cleaned, and the new ceramic block can be fixed by aligning with the卡槽. The maintenance time for a single time is 40 to 60 minutes. The cyclone feed valve of a certain dense medium concentrator originally used high-chromium cast iron liners, with a service life of only 6 months, and each replacement required a 6-hour shutdown. After switching to disassembly-free alumina ceramic liners, the service life was increased to 18 to 24 months, the single maintenance time was only 50 minutes, and the annual shutdown loss was reduced by about 85%. However, ceramic accessories have high brittleness and cannot withstand the direct impact of large ore blocks. A protective grille needs to be installed at the valve inlet, and the one-time procurement cost is 30% to 50% higher than that of cast alloys, resulting in high initial investment costs. They are more suitable for scenarios with high loads and long operation cycles.

For different mining working conditions, the selection of wear-resistant parts for disassembly-free mining valves needs to be comprehensively judged based on abrasion grade, material characteristics and operation and maintenance costs. For working conditions with low abrasion and fine particles (such as the flotation process), rubber accessories are preferred to balance the sealing performance and maintenance efficiency; for working conditions with medium abrasion and corrosion (such as concentrate conveying), polyurethane accessories are selected to balance wear resistance and lightweight; for working conditions with high abrasion and no impact (such as tailings discharge), wear-resistant ceramic accessories are chosen to maximize the service life; for working conditions with high abrasion and impact (such as ball mill discharge), cast alloy accessories are selected to balance wear resistance and impact resistance. A certain iron ore concentrator in northern China replaced the slurry gate valve, flotation feed valve and tailings discharge valve with disassembly-free wear-resistant parts made of polyurethane, rubber and wear-resistant ceramic respectively through matching selection. The annual maintenance time was reduced from the original 480 hours to 60 hours, the annual operation and maintenance costs were saved by more than 3 million yuan, and the output loss of about 12,000 tons was reduced.