Grinding Sludge Goes Green. Briquetting for the Environment

Manufacturers of wind turbines, heavy machinery, gear grinders, bearings, and other industrial products constantly struggle with how to safely and efficiently dispose of the grinding sludge produced during the manufacturing processes. This is especially true of the large volumes of sludge that are created during the grinding of high-precision gears.

Although grinding is necessary to achieve the desired precision and finishes of many end products, the grinding sludge it creates poses a problem. The sludge often consists of very small metal chips and grinding oil, so when the manufacturers dispose of it, they’re paying high prices and wasting potentially valuable commodities. Manufacturers have wrestled with this issue for decades.

In most cases, disposing of grinding sludge is expensive and time-consuming. For the manufacturing processes to be accurate, large amounts of oil and fluids are used, but nearly 50% to 60% of them are wasted. Fortunately, today’s sludge-producing industries have found an environmentally sustainable, cleaner, and more cost-efficient way to dispose of their waste, while recovering some of the value trapped inside the sludge—briquetting. This method of sludge waste disposition has been gaining momentum in Europe for years, and is becoming increasingly popular in North America.

Briquetting Explained

At its most basic level, briquetting is a process that compresses materials from metal grinding chips into compact, easy-to-manage cylindrical blocks (briquettes), with densities and resale values that rival those of near-solid metals. When briquetting is applied to grinding sludge, a significant amount of oil can be recovered and recycled, as well.

Briquetting boosts the bottom lines of manufacturers by adding value to the waste stream. For a relatively small investment, briquetting reduces energy, as well as labor and transportation costs, while increasing revenues.

Saving Resources

Without using a briquetter, manufacturers that produce grinding sludge as a by-product are paying high prices to dispose of valuable commodities and adding to landfills. In some cases, manufacturers have several full-time employees dedicated to disposing of the dirty grinding sludge, which results from manufacturing processes. The sludge is thick, heavy, and difficult to transport. What’s worse is the sludge usually contains potentially hazardous materials, so there’s an added expense to disposing of it properly.

Briquetting solves these problems. Briquetting systems are good for the environment and good for business, with an excellent return on investment that comes with little to no direct supervision during operation.

To briquette grinding sludge, it must first be transferred from the machine into the briquetter. Once inside, the sludge is compressed—squeezing out excess oils and fluids—while transforming the metal chips into metal briquettes. The oil pressed out during the briquetting process can be pumped directly from the briquetter into tanks. Next, it can be passed through a filter so the oil can be easily recycled and reused. The metal briquettes that are extracted from the sludge can be transported and recycled, rather than being sent to landfills where they can harm the environment.

Manufacturers that briquette their grinding sludge often reuse the salvaged oil themselves, and resell the briquettes wherever they sell other steel chips. In most cases, a manufacturer’s briquetting system will pay for itself in less than a year, thanks to the savings from reclaimed waste and the reduced operational costs.

As briquetting grinding sludge becomes more common throughout North America, its benefits to manufacturers and the environment will continue to grow.

RUF is the North American subsidiary of RUF GmbH & Co. K in Germany, a global pioneer of advanced briquetting systems, with more than 5,500 currently in operation.