The Indian steel manufacturing industry is one of the biggest in the world. Steel is largely sourced from iron ore and is then manufactured into the final product. Steel is a vital component used by various industries such as construction, electric and real estate. The growth of the steel industry is also constantly on the rise and this cause a parallel increase in the pollution caused by the industry as well. The manufacturing process of the steel industry leads to the emissions of several pollutants like fugitive dust and particulate matter.
Manufacturing process of the steel industry:
In the various steps of manufacturing steel, there are pollutants of a wide variety that are released into the air.
- Mining ore: the first step of mining ore leads to pollutants such as sulfur and carbon di oxide apart from particulate matter and fugitive dust are introduced and emitted into the air. This step mainly used coal for blasting and the fuel also emits unaccounted pollutants.
Cake oven emissions refer to a mixture of coal tar, VC and chromium that are deadly to human health and lead to various health issues in the long run.
- Blast furnace: the blast furnace simply refers to a step where iron ore is melted into liquid form using the basic oxygen method. A mixture of various fluxing agents such as limestone are introduced into the furnace to form various forms of metals such as pig iron and crude iron, that are used for other work are further processed. The pollutants introduced at this stage are various hydrocarbons, nitrogen di oxide and sulfur di oxide.
An alternative to this blast furnace is an electric arc furnace that uses high temperatures to melt the scrap steel from the plant instead of pig iron. However, even the use of these types of furnaces leads to the production of pollutants such as carbon monoxide, carbon di oxide, hydrocarbons, sulfur di oxide and nitrogen di oxide.
- Steel making: this refers to a step where the steel is bent and shaped in a certain desired way. The steel can also be welded, be coated with zinc and tempered with heat to arrive at the right final product. This stage leads to the emission of various deadly particulate matters and oxides of carbon.
Sustainable practices that can be followed by the steel industry:
The first step for the steel industry to succeed in finding sustainable alternatives to existing sources of problems is identifying and acknowledging the increasing pollution levels. This not only helps in implementing safe modes of work for the employees but also ensures that the environment in and around that area is not degraded and destroyed.
The steel industry has already identified and started using certain sustainable modes to reduce pollution. Few of the green practices are:
Packaging with steel: steel is known to be an excellent contributor to the circular economy as it can be extensively recycled and remade without any major loss to quantity. Various companies have started taking advantage of this feature and have started using steel to package consumer goods such as shampoos and conditioners.
Light steel frame construction: this refers to a type of construction of steel that involves pre-engineered parts that are easy to set up and dismantle. Steel frame constructions involve much less extensive foundations and lesser time as well. Thus, these frames help in reducing the pollutants and fugitive emissions at a construction site.
Use of slag: lately, steel companies across the world have started using containers made out of slag, which is a byproduct in the steel manufacturing process itself. Slag is a dense, thick, rock like material. Using slag helps in the desertification of marine algae forests.
The steel industry is known to be the third largest contributor to air pollution is one of the biggest contributors to the emissions of carbon di oxide in the country. The process of manufacturing of steel primarily requires coal for energy. The combustion of coal cause a release of multiple pollutants such as particulate matter, carbon di oxide, nitrogen oxides, carbon monoxide, sulfur oxides etc.
Existing pollution control methods employed by the steel industry:
The steel industry uses pollution control equipment’s that conventionally include point source pollution control equipment’s like electrostatic precipitators, bag houses, industrial scrubbers and jet filters. However, all these sources have a limited scope of efficiency and work only in the defined area. Thus, they cannot successfully control fugitive emissions and ambient air pollution across the entire manufacturing unit. Furthermore, the above mentioned methods are extremely energy consuming and require high maintenance.
xThe major challenge faced by the steel industry is dust emissions that are not accounted for and are commonly known as fugitive emissions. These pollutants are released into the air without knowing the exact source that is causing this pollution. Regular emissions can be accounted for as their source is known, hence, they can be controlled. The problem and emissions of fugitive dust occurs at every single stage of manufacturing steel.
A lot of steel industries are not following the practice of successful pollution control in an optimum manner. With an increase in production output, due to the ever rising demand, even the pollution levels are drastically increasing across the entire industry. Thus, the problem of air pollution by the steel industry must be addressed immediately and in totality to actual create an impactful solution.
Common practices such as carbon capture and sequestration help in removing carbon di oxide at source in industrial plants. But these practices are extremely expensive and require a lot of energy which in turn cause more pollution. Hence they are not sustainable in the long term.
An ideal solution for the air pollution problem faced by the steel industry should be able to successfully deliver a three-fold result. It should be cost effective and sustainable while addressing the problem of fugitive emissions. Apart from this, it should also solve the problem of accounted air pollution at the same time.