Iron and steel plants require very high levels of investment due to the scale of their equipment and the length of their production lines. Achieving a return on these investments as quickly as possible requires reliable operation with low operating and maintenance costs and minimal unplanned downtime.

Every unplanned event can result in significant revenue losses. At the same time, each component of the steel production process is expected to produce greater quantities of steel year after year while maintaining quality standards and complying with increasingly stringent environmental requirements.

The Importance of Lubrication in the Steel Industry

Lubrication plays a major role in helping the steel industry achieve these objectives. According to SKF data, approximately 36% of bearing failures are associated with insufficient, incorrect or improper lubrication. This highlights the need for a wide range of lubrication solutions designed specifically for the extreme requirements of the industry.

For iron and steel producers to achieve their annual production targets, lubrication must be designed for components exposed to high temperatures, heavy loads and continuous vibration, as well as contamination from water, steam, acids and other process-related substances.

Engineering collaboration is essential to achieve longer equipment life, increased operating time and reduced lubricant consumption.

Although most applications in the iron and steel industry push lubricants to their limits, each stage of the production process demands different performance characteristics from the lubricant.

Calcium sulphonate complex greases have a chemical structure capable of responding to almost all of these demanding conditions, regardless of the stage of the steel production process.

Performance of Calcium Sulphonate Complex Greases

Calcium sulphonate complex greases provide an excellent technology for applications involving heat, water, high loads or shock loads.

They offer excellent rust and wear protection, high load-carrying capacity, a high dropping point and very good mechanical stability even in the presence of water.

Unlike many other grease types, these performance characteristics can be achieved without the use of additional raw materials.

Calcium sulphonate complex greases are successfully used not only in iron and steel plants, but also in marine applications, paper mills, off-road machinery, construction and mining equipment, and even in the food processing industry.

Experimental Studies

Overbased calcium sulphonates contain large quantities of amorphous calcium carbonate dispersed within the sulphonate matrix. In the presence of suitable chemicals, such as high-boiling-point alcohols and acids, and within the appropriate temperature range, the gelation process causes amorphous calcium carbonate to transform into crystalline calcite.

Because the particle size of the dispersed calcite phase is within the nano range of approximately 4–5 nm, it provides an extremely high surface area and forms a stable gel structure strong enough to produce a grease-like consistency.

Reaction Conditions and Dehydration

An important consideration during this process is the use of a suitable reactor operating at an average pressure of approximately 50 psi. At this stage, the grease still contains water as a result of the reaction and must therefore be dehydrated to produce the final lubricating grease.

The material at this stage is commonly referred to as calcium sulphonate gel or calcium sulphonate grease.

During this process, highly overbased calcium sulphonates should typically be prepared in a closed and pressurized reactor at approximately 50 psi by reacting suitable acids, based on stoichiometric calculations, in the presence of calcium oxide and carbon dioxide.

Formation of the Complex Structure

Following the conversion stage in calcium sulphonate grease chemistry, complexity is developed through the addition of calcium oxide or, more commonly, calcium hydroxide, followed by reaction with boric acid, acetic acid and 12-hydroxystearic acid.

During the development of the production technology, not all excess calcium oxide or hydroxide should be converted into amorphous calcium carbonate. Time and pressure are therefore extremely important parameters at this stage.

As a result of our laboratory studies, changes in FTIR results and various performance characteristics can be observed as a function of reaction time and pressure.