Repurposing Industrial Waste: Lime Slurry

Huge amounts of industrial waste are generated around the world. This waste can be harmful to the environment if not disposed properly, or the disposal of the same could lead to very high costs. On the other hand, utilizing industrial waste as secondary raw materials for other industries could not only reduce costs and save the planet, but also serve as a supplementary source of income. Since lime is used in several industries, lime slurry can be treated and used in many applications.

The rising rates of carbide lime waste (CLW), commonly known as lime slurry produced as a byproduct of industrial production of acetylene, has warranted the need for repurposing of the said material.

How Lime Slurry Is Produced in the Acetylene Production Process?

In the acetylene production process, carbide is mixed with water to produce acetylene, carbide lime or lime slurry, and heat.

The formula for this process:

The final products are suspended in water. Thus, when calcium hydroxide mixes with water, it produces CLW.

Once, the water is evaporated or dried, the lime slurry produced is in solid form. This makes disposal tedious and expensive. Hence, utilization of lime slurry in other industrial applications has proved to be beneficial for both the suppliers and users.

In the initial stages, several chemical tests and X-ray diffraction analysis were carried out to determine the constituents of lime slurry. It was noted that with the exception of presence of carbon, lime slurry was very similar to industrial lime. Hence, the process of treating and repurposing lime slurry was put in place.

Methods of Repurposing Lime Slurry

Once seen as a liability and cost, proper repurposing of lime slurry can bring in a profit. Here are listed some methods of re-using carbide lime waste:

1. 1. Chemical processing plants for various purposes

1. 1. Can be used in controlling the pH levels of industrial acids

1. 1. Helpful in the process of dehalogenation – The process of producing organic chemicals

1. 1. Lime slurry can be used in wastewater treatment plants for removal of:
      • Bacteria
      • Turbidity
      • Suspended solids and heavy metals

1. 1. It can be used in processes like compounding and sand washing when manufacturing glass

1. 1. It can also be used in construction to produce concrete and bricks

1. 1. When added to soil, it can provide conditioning.

1. It can assist in reducing sulfur concentrations in petroleum refitting.

Repurposing Lime Slurry: Points of Consideration

If, as a manufacturer, or intermediary, you consider getting into the lime slurry market, you need to consider the following factors:

1. 1. Lime slurry in its raw form, may not be fit for use in other industries. Depending on the chemical composition of the CLW, you will need to chemically treat it to make it useful for another industry. Since CLW differs in chemical composition depending on the process, location, and nature of raw material, you can consult a chemical engineer. He/ She will be able to guide you in the most time and cost efficient manner of treating lime slurry.

1. 1. Taking chemical and physical tests of the lime slurry will help you determine in which industries it can be used. Depending on the buyer’s needs, you can treat the lime slurry accordingly.

1. 1. Repurposing of lime slurry may not always be possible. After taking chemical tests and forming a budget, if selling lime slurry doesn’t work in your favor, you will need to dispose of it. There are strict regulations regarding the disposal of industrial waste.

1. 1. Whether you are treating and repurposing the lime slurry, or disposing of it, you need to follow all rules and regulations. This includes national, state, and local laws, as well as any international or private standards that your company is currently adhering to. Keeping all these authorities in mind, you will need to check their rules on usage and disposal of lime slurry.

1. Stakeholders, buyers, and end users will be deeply concerned about the manufacturer’s stand on recycling, and repurposing of products. You must ensure that these practices are in tune with your company policies.

The industrial waste produced by acetylene manufacturing plants can prove to be a boon. Manufacturing and processing methods and applications can be adjusted for effective usage of lime slurry. Using the byproducts of one industry as the raw material of another can help in providing a better industrial working culture. This method not only saves costs, increases employment, reduces wastage, and makes the planet greener.