The production environment of underground mines features strong corrosion, high abrasion and complex impact characteristics. As the core control components for material conveying and chemical dosing, valves operate under long-term high-load working conditions. For most small and medium-sized underground mines in China, the replacement cycle of valve accessories is only 15-30 days, with the annual replacement cost generally exceeding 1.5 million yuan, and a single shutdown replacement takes more than 8 hours, directly causing monthly production capacity loss of over 3%. To address this industry pain point, it is necessary to match wear-resistant parts of corrosion-resistant mine valves suitable for the specific underground working conditions. A detailed analysis is carried out below from four core categories.

Rubbon Wear-resistant Parts: Suitable for Weakly Corrosive Downhole Sealing and Conveying Scenarios

Wear-resistant rubber valve parts are mainly made of nitrile rubber, fluororubber, and natural rubber as base materials, and the sealing surfaces, valve body liners and other components are made by compression molding. Its core advantages lie in excellent elasticity and stable sealing performance, which can effectively avoid medium leakage, and its cost is lower than that of the other three types of fittings. In weakly corrosive downhole scenarios, such as the clean water dosing valves in the flotation workshop and the gravity flow valves for fine tailings particles, the service life of ordinary nitrile rubber fittings can reach 60-90 days, and fluororubber materials can further increase it to 120 days, suitable for weakly acidic and alkaline media with a pH value of 5-9. For the dosing valves in the downhole flotation workshop of a certain copper mine, natural rubber seals were originally used, which needed to be replaced once a month with a replacement cost of about 800 yuan each time. After replacing with fluororubber seals, the replacement cycle was extended to 4 months, saving about 22,000 yuan in replacement costs annually. It should be noted that the upper temperature limit of rubber fittings is about 120°C, and they cannot resist the erosion of strong acidic or strong alkaline media. Their service life will be shortened to less than 30 days in the downhole high-concentration sulfide slurry environment, so they are only suitable for downhole conveying scenarios with weak corrosion and low abrasion. Compared with polyurethane fittings, rubber has better temperature resistance and can be applied to downhole hot water conveying valve scenarios, while polyurethane will soften and deform in media above 80°C.

Casting Alloy Wear-Resistant Parts: Suitable for Core Downhole Working Conditions with High Abrasion and High Corrosion

Wear-resistant parts made of cast alloys take high-chromium cast iron, chromium-molybdenum alloy and high-manganese steel as the main base materials and are formed through the lost foam precision casting process. The surface hardness of the valve body can reach HRC58-62. The core advantage of such parts lies in their balanced wear resistance and impact resistance, enabling them to cope with severe wear and corrosion scenarios such as the outlet of downhole slurry pumps, the discharge of ball mills and the discharge of crushing stations. Taking the gate valve at the outlet of the downhole slurry pump of a large domestic iron mine as an example, the service life of the original ordinary high-manganese steel parts was only 30 days, while after replacing them with high-chromium cast iron parts, the service life was increased to 90-120 days, which is 2-3 times longer under the same working conditions. For the discharge valve of the downhole ball mill of an iron mine, the original ordinary high-manganese steel valve body had a service life of only 30 days. After replacing it with a high-chromium cast iron valve body, the service life reached 95 days. Each single valve saves about 12,000 yuan in replacement costs per year and also reduces downtime by about 120 hours per year. Cast alloy parts can adapt to strongly corrosive media with a pH value of 3-11, and at the same time resist the abrasion of high-hardness ore pulp containing more than 15% quartz sand, making them the mainstream choice for downhole mine valve parts at present. However, it should be noted that the toughness of high-chromium alloy parts is slightly lower than that of high-manganese steel. In scenarios with frequent impacts, modified high-chromium alloys added with nickel elements should be selected to avoid valve body cracking.

Polyurethane Wear-resistant Parts: Suitable for High-abrasion and Low-corrosion Underground Conveying Scenarios

Polyurethane valve wear-resistant parts take cast polyurethane as the base material and are made into valve liners, seals and other components through casting. Their Shore hardness can reach Shore A60-90, with wear resistance 3-5 times that of ordinary rubber, and they have excellent oil resistance and weak corrosion resistance. In underground high-abrasion and low-corrosion scenarios, such as butterfly valves for flotation tailings conveying pipelines and discharge valves of dewatering screens, the service life of ordinary rubber accessories is only 45 days, while that of polyurethane accessories can reach 180-240 days. For the discharge butterfly valve of the underground dewatering screen of a gold mine, the original nitrile rubber liner had a service life of only 45 days. After replacing it with a polyurethane liner, the service life reached 180 days, and a single valve saves about 15,000 yuan in replacement costs annually. Another advantage of polyurethane accessories is that their weight is only 1/3 of that of metal accessories, which can reduce the labor intensity of valve installation, and no large hoisting equipment is required during installation. It should be noted that the upper temperature limit of polyurethane accessories is about 80°C, which cannot be adapted to underground high-temperature slurry scenarios, and they will swell in strong acidic media (pH<3), so they are only suitable for low-corrosion and high-abrasion scenarios with a pH value of 4-10. Compared with ceramic accessories, polyurethane has stronger toughness, can resist slight impacts, and will not have the problem of brittle fracture.

Wear-resistant ceramic accessories: Suitable for extreme strong corrosion and no impact working conditions

Wear-resistant ceramic valve parts take alumina ceramics and silicon nitride ceramics as the base materials, and are sintered and formed to make components such as valve liners and valve cores. Their hardness can reach HRA88-92, the wear resistance is 5 to 7 times that of high-manganese steel, and they have excellent strong corrosion resistance, which can be adapted to acidic and alkaline media with a pH value of 1-14. In extreme strong corrosion underground scenarios, such as underflow valves in lead-zinc ore flotation tanks and stop valves for acidic ore slurry transportation, the service life of the originally used high-chromium alloy parts is only 20 days, while after replacing them with alumina ceramic parts, the service life can reach 180 to 240 days. For a stop valve used for transporting acidic ore slurry in a lead-zinc mine underground, the originally used high-chromium alloy valve body had a service life of only 20 days, but after replacing it with an alumina ceramic valve body, the service life reached 210 days, saving approximately 25,000 yuan in annual replacement costs per single valve. However, ceramic parts have high brittleness and cannot withstand frequent impact loads, so they are only suitable for non-impulsive gravity flow transportation and low-pressure transportation scenarios. Rubber buffer pads need to be installed during installation to prevent ceramic fragmentation caused by material impact. At present, most large domestic underground mines have begun to apply ceramic valve wear-resistant parts, and in the scenario of strong corrosion tailings treatment, the annual replacement cost can be reduced by more than 60%.