We are looking for alternate uses of the used lubricant powder generated from wire drawing machines.
Steel wires are made by passing wire rods through conically converging dies as shown in this video. As a result of the pulling force on the wire rods through the converging section, the diameter of the wire is reduced. This reduction in diameter of the wires is a gradual process, and it takes place by passing the wires through a sequence of dies with gradually decreasing converging sections. These wire drawing dies are made of sintered tungsten carbide (WC).
For the purpose of lubrication, dry lubricants are used which forms a thin layer between the wire and die surface to prevent direct contact between wire material and die & reduce friction. Calcium and sodium stearate soap powders are mainly used as dry lubricants.
The major constituents of the dry lubricant are:
(a) Calcium Stearate – FAT (animal or vegetable) + Calcium Hydroxide.
(b) Titanium dioxide – 3 to 12%.
(c) Lime and Calcium Sulphate as fillers.
The heat generated during the wire drawing process burns the dry lubricants, which are in direct contact with the die. The used dry lubricants are collected as burnt lubricants and discarded. The wires get marginally heated up during sequential wire drawing process and this heat is carried forward to subsequent stages. While passing through the next sequence of die, this heat is transmitted to the lubricant chamber, causing partial burning of the lubricant, which generates fine burnt powders. As time passes, the burnt component in the soap powder increases, resulting in improper lubrication. Thus, this used lubricant needs to be replaced with fresh lubricant. A gradual increase in burnt components is observed from the first die box to the last die box.
Approximately 25 MT of used dry lubricant is generated per month. Since this used dry lubricant is a mixture of burnt and unburnt powders, the unburnt powder can be recycled as it has been validated as non-hazardous waste. The used lubricant was discarded by incineration. The calorific value (CV) of used powder is > 3000 and as per Waste Management Rule, any waste having CV >2500 cannot be discarded in a landfill. As the CV of burnt powder is in the range of 3300 to 3800, it can be used as an alternative fuel.
Thus, we are seeking alternate uses of this used soap powder, either as an alternative fuel or as raw material.
- A magnetic separator was installed to separate unburnt soap powder. However, due to the very high speed of wire drawing machines, it was not feasible.
- Since the Calorific value is high, it cannot be discarded in landfills.
- Recycled lubricant powder is a mixture of Na and Ca powder in the form of fines. This powder is not suitable as a lubricant in high-speed wire drawing machines.
- The used powder could be sold to wire manufacturers having low-speed wire drawing machines.
- The used powder could be sold as an alternative fuel.
- The used soap powder can be sold to the manufacturers to use it as raw materials.
- We should not incur any cost in disposing of the used lubricant.
- The customer should collect the used lubricant powder from our storage location. We will not transport it to them.
- Recycled soap powder is a mixture of Na and Ca-based soap powder in the form of fines. This can be used in low speed and non-critical wire drawing processes only.
- Separation of unburnt components from the soap powder is highly complex.
- Direct use as fuel may cause higher particulate matter (PM) in stack emission due to the presence of burnt components.
Awards:- INR 5,00,000