In the scenarios of domestic metal ore and non-metal ore beneficiation and tailings resource utilization, high-concentration slurry ball mills are core grinding equipment. Their wear parts are subjected to long-term impacts from high-hardness ore particles, slurry scouring and chemical corrosion. Traditional accessories often suffer from early wear, fragmentation and other issues, resulting in an annual shutdown replacement cost of over 500,000 yuan per ball mill and an increase of 12-18 hours in monthly shutdown time. To address this industry pain point, it is necessary to accurately match four types of wear parts—rubber, cast alloy, polyurethane and wear-resistant ceramic—according to the grinding stage, slurry concentration and ore characteristics to ensure the durability under working conditions.

Rubber-type wear parts: Buffer and wear-resistant solution for rough grinding conditions

Rubber-type wear parts mostly adopt a composite formula of natural rubber and nitrile rubber, with a Shore A hardness controlled in the range of 60-70. They possess excellent impact buffering performance and are suitable for steel ball impact and slurry scouring in the rough grinding section of ball mills (feed particle size > 20mm). A certain iron ore concentrator in Hebei originally used ordinary carbon steel liners, and the liners in the rough grinding section needed to be replaced every 3,000 hours, with a single replacement cost of about 80,000 yuan, and the replacement process required 2 workers to take 4 hours to complete. After switching to composite rubber liners, the service life was increased to 8,500 hours, and the annual single-unit replacement cost was reduced by 62%. Moreover, the damping characteristics of rubber can reduce the operating noise of ball mills by 3-5 decibels, improving the underground operation environment. At the same time, the weight of rubber accessories is only 40% of that of high-manganese steel liners of the same size, which reduces the labor cost and labor intensity of hoisting and replacement, and is suitable for rough grinding working conditions with frequent replacement requirements.

Casting Alloy Wear Parts: The Core Choice for High-Hardness Abrasive Wear Scenarios

Casting alloy wear-resistant parts mainly include high manganese steel, high chromium alloy, wear-resistant white cast iron and other categories. Among them, Cr26-Cr30 high chromium alloy has a hardness of up to HRC60-65, with excellent abrasive wear resistance, and is suitable for grinding conditions of high-concentration slurry (solid concentration ≥65%) in the fine grinding stage (feed particle size <10mm). A copper concentrator in Jiangxi originally used high manganese steel liners, and the service life of the liners in the fine grinding stage was only 4,500 hours, with local cracking and failure problems, and the annual replacement cost exceeded 600,000 yuan. After replacing with Cr28 high chromium alloy liners, the service life was increased to 12,000 hours, the annual number of shutdowns for replacement of a single ball mill was reduced from 2 to 0.7 times, and the annual shutdown loss was reduced by about 1.35 million yuan. It should be noted that high chromium alloy has slightly lower toughness, and it is necessary to avoid using it in the rough grinding stage containing large ore materials, otherwise fracture failure is likely to occur.

Polyurethane wear parts: A full-working-condition adaptable choice balancing wear resistance and corrosion resistance

Polyurethane wear parts take cast polyurethane as the base material. The hardness can be adjusted from Shore D 40 to 80 by formulating the formula, endowing them with excellent wear resistance, impact resistance and chemical corrosion resistance. They are suitable for scenarios where high-concentration slurry contains a small amount of corrosive media (such as sulfides and cyanides). The end cover liners of the ball mill in a gold ore dressing plant in Heilongjiang were originally made of rubber. Due to corrosion by a small amount of cyanide in the slurry, their service life was only 6,000 hours, and anti-corrosion repair was required every quarter. After switching to cast polyurethane liners, the service life was increased to 9,500 hours without additional anti-corrosion treatment, and the annual replacement cost per unit was reduced by 48%. In addition, the friction coefficient of polyurethane accessories is only 0.2-0.3, which can reduce the power consumption during the operation of the ball mill. The actual measurement shows that the motor load can be reduced by 3%-5%, further saving operating costs.

Wear-resistant ceramic wear parts: the ultimate wear-resistant solution for fine grinding of ultra-hard ores

Wear-resistant ceramic wear parts are mainly made of 92% alumina and 95% alumina as the base material, with a hardness of up to HRA85-90. They are one of the wear-resistant materials with the best wear resistance at present, and are suitable for high-concentration slurry working conditions of fine-grinding high-hardness ore materials (such as quartz sand, iron ore, Mohs hardness ≥ 7). A quartz sand concentrator in Jiangsu originally used steel balls as the grinding medium in the ball mill. The service life of the grinding balls was only 2000 hours, and 1.2 tons of steel balls needed to be replenished every month, with the annual steel ball consumption cost exceeding 800,000 yuan. After switching to 95% alumina ceramic grinding balls, the service life was increased to 12000 hours, and the annual steel ball consumption cost was reduced by 92%. It should be noted that ceramic materials have high brittleness and need to be used with a rubber buffer layer to avoid ceramic fragmentation caused by direct impact of steel balls. At the same time, the loading capacity of the ball mill should be controlled to avoid stress concentration caused by overfilling.

The selection logic for wear parts for different working conditions needs to be comprehensively judged by combining the grinding stage, slurry concentration and ore hardness: for the rough grinding stage (feed particle size > 20mm), rubber or high-chromium alloy accessories are preferred to balance cushioning and wear resistance; for the fine grinding stage (feed particle size < 10mm), polyurethane or wear-resistant ceramic accessories are prioritized to improve the resistance to abrasive wear; for high-concentration slurry scenarios with a solid concentration of ≥ 70%, high-chromium alloy or wear-resistant ceramic accessories are preferred to enhance wear resistance; for ore with a Mohs hardness of ≥ 7, wear-resistant ceramic accessories are prioritized, and for ore with a Mohs hardness of < 7, polyurethane or high-chromium alloy accessories can be selected. Accurate selection of the four major types of wear parts can effectively reduce the accessory replacement costs and shutdown losses of mining enterprises and ensure the long-term stable operation of ball mill working conditions.