Grinding Swarf

A growing waste problem in the State of Iowa, and other industrial centers, is the land filling of what is technically known as grinding swarf or hone sludge. This material is really just a combination of finely ground metal particles and abrasive material suspended in some type of coolant. Depending on the type of coolant used, the waste may be able to be land filled. However, some plants that use a heavy petroleum based coolant (because of the specific operation) run into regulations that classify the sludge as a hazardous waste, which could run upwards of $400.00 a barrel to have removed. The other problem is that environmental regulations usually lag behind technology, meaning, that which is able to be land filled today, may not be tomorrow. That is why (during this lead time) many companies are taking a pro-active approach to waste management and looking for viable recycling alternatives to reduce their need to landfill waste. The mind-set of industry has to change from that of looking at these materials as waste to that of looking at these materials as a valuable commodity. The Materials Innovation Service (MIS) and the Recycling & Reuse Technology Transfer Center (RRTTC) at the University of Northern Iowa is dedicated to this very premise and is actively seeking alternative uses for this and other materials.


When looking into possible alternative uses for current waste materials, it is important to know the exact composition of the material. Many companies have had their waste analyzed and will have this data available. Then, look at the strengths and weaknesses of the material (i.e., hard soft, weak, strong, conductive, corrosive etc.?). Next, it is important to do a little background research. There is no point in re-inventing the wheel. Find out what has been done, what showed promise, and what has failed, keeping in mind that some failed attempts for a specific use, turn out to be quite profitable when put to another use. This will also allow you to expand your thinking and explore new possibilities. Lastly, develop a plan of attack and research various ASTM and other standards to help you in preparing a certain methodology and tests that need to be performed to prove your ideas.


Currently, the MIS is working with a company in finding alternative uses for the grinding swarf produced at their Eastern Iowa plant. Areas in which testing is currently underway are: 1) Looking into the possible use of their grinding swarf as a filler material in concrete by testing mechanical properties (e.g., compression, split tensile, flexure, stiffness and toughness); 2) The possible conductive properties of the metal particles through resistivity and conductivity testing; and 3) Sieve analysis of the dried swarf to characterize the size of the solid particles involved.