1. Current Contamination Status of Aluminum Rolling Oil and Pain Points of Traditional Purification Processes

Aluminum rolling production is a continuous and high-intensity operation, in which rolling oil is recycled repeatedly in a closed-loop circulation system. Affected by multiple factors such as high-temperature shearing, metal friction and air oxidation, the rolling oil gets contaminated at a fast speed with complex impurity components. The main pollutants include micron-level and even nano-level fine aluminum scraps, oil-soluble metal compounds, free water and emulsified water, colloidal asphaltenes formed by oxidation, and various polar organic impurities.

Failure to remove these impurities in a timely manner will trigger a string of production problems: firstly, it causes defects such as scratches, roll marks, pinholes and oil stains on the surface of aluminum sheets and plates, drastically reducing the qualified rate of finished products; this impact is particularly critical for high-precision aluminum foils and decorative aluminum panels. Secondly, it damages the lubricating film of rolling oil, intensifies the wear of rolling rolls, shortens equipment maintenance cycles, and increases downtime losses. Thirdly, it accelerates the aging and deterioration of rolling oil, shortens oil replacement cycles, and significantly drives up the procurement cost of new rolling oil. Fourthly, oil-containing filter residues and waste filter aids generated by traditional purification are classified as hazardous wastes, which involve cumbersome disposal procedures, high costs and potential environmental compliance risks.

At present, the mainstream traditional rolling oil purification processes in the industry mainly include plate filtration, vacuum filtration, diatomite/white clay adsorption and centrifugal separation, all of which have unavoidable shortcomings. The diatomite and white clay filtration process can only remove part of large-particle impurities, with poor adsorption effect on nano-level fine powder and polar oxides; in addition, the oil content of filter cakes reaches as high as 25%-30%, resulting in massive oil waste, and the waste filter residues are hazardous wastes with high disposal costs.

Centrifugal separation has limited effect in removing emulsified water and colloidal impurities, and fails to meet the purification accuracy requirements for aluminum production. Conventional precision filtration can only intercept solid particles, but cannot degrade oxidation products in the oil, making it impossible to restore the original performance of rolling oil. Some heating dehydration processes further accelerate oil oxidation, forming a vicious cycle. On the whole, traditional processes can hardly balance purification accuracy, oil recovery rate, operating cost and environmental protection requirements, and are no longer compatible with the high-quality and green production demands of the modern aluminum processing industry.

2. Core Principle of Electrosorption Purification Technology by Qingdao Haina Energy

As a national high-tech enterprise, Qingdao Haina Energy has been deeply engaged in the field of industrial oil purification for more than ten years, focusing on the research and development of continuous physical electrosorption refining and purification technology. The company owns more than ten invention patents and over 40 utility model patents, and its electrosorption purification technology has been selected into the Catalog of Major Environmental Protection Technical Equipment Encouraged for Development by the State.

This is an innovative physical purification technology specially designed for special industrial oils such as waste industrial oil and rolling oil. The whole process requires no heating, no chemical additives and no distillation, realizing pure physical and green purification.

The core principle of this technology is to form a directional electric field through special electrode materials, and actively adsorb charged impurities in rolling oil (including metal ions, oxidized polar substances, colloidal impurities and micro-particle pollutants) via the driving force of the electric field. Meanwhile, it breaks the oil-water emulsification structure to achieve demulsification and dehydration.

Different from the traditional passive filtration and physical adsorption modes, Haina’s electrosorption technology is powered by electricity. Through the special structure of electrode materials and electric field regulation, it can accurately capture polar impurities and tiny particles in the oil. It not only removes solid suspended impurities, but also purifies oxidation products and removes free water and emulsified water, restoring the basic physical and chemical properties of rolling oil in the operating system — including viscosity, acid value, cleanliness and lubrication performance — to a level close to that of new oil, thus realizing the recycling and regeneration of waste oil.

3. Application Value and Industrial Significance of Electrosorption Technology in Aluminum Rolling Oil Purification

Nowadays, competition in the aluminum processing industry is increasingly fierce and environmental protection regulations are becoming stricter. Cost reduction, efficiency improvement, green development and low-carbon operation have become the core competitiveness of enterprises. The electrosorption purification technology developed by Qingdao Haina Energy breaks the technical bottleneck of traditional rolling oil purification, achieving the unification of three major benefits: purification and quality improvement, cost and consumption reduction, and environmental protection and emission reduction.

For aluminum processing enterprises, the application of this technology can not only steadily improve product quality and ensure the production accuracy of high-end aluminum products, but also significantly cut down the costs of oil procurement and hazardous waste disposal, alleviating environmental protection pressure. From the perspective of industrial development, this technology promotes the transformation of aluminum rolling oil from “one-time consumption” to “recyclable regeneration”, helps the industry realize efficient resource utilization, complies with the national dual-carbon strategy and circular economy development requirements, and drives the aluminum processing industry to transform and upgrade towards greenization and intellectualization.