Sodium silicate made from rice husks is a natural resource that can generate wealth from waste, promote sustainable use of raw materials and lead to national development, especially in developing countries like Nigeria.
The world’s industrial production processes are gradually being tailored towards the more sustainable use of raw materials to reduce environmental degradation caused by the high tendency of pollution of raw materials, high energy requirements and emission of harmful gases like carbon dioxide.
Sodium silicate is a clear, sticky, liquid, semi-solid or solid viscous substance that has immense potential for wealth creation from waste. It has wide applications in various industries, such as silica gel, detergent, packaging industries, cement of glass, pottery and stoneware, fireproof paper, absorbents, abrasive particles, refractory, binder for inorganic paint, preserving eggs and many other applications.
In Nigeria, the demand for sodium silicate exceeds 20,000 metric tonnes per annum and most industries import it from India, China and Egypt. The rice husk, which is the outer cover of the rice, accounts for 20 per cent of the paddy produced worldwide. About 190 million tonnes of rice husk was produced in 2016 alone and it has various applications in industries. It is used as an industrial fuel for processing paddy and the generation of process steam in power plants. It is also used as a fertiliser and substrate of pet food fibre and as a raw material for brick production. Rice husk ash is also used as an ingredient for the preparation of activated carbon or substrate for silica and silicon compound production.
The chief executive officer of Jola Global Industries Limited, Dr. Moses Omojola explained that the expanding industrial use of sodium silicate has led to an increase in its demand and global production.
In 2021, the market volume of sodium silicate worldwide amounted to 26.65 million metric tonnes and it is forecast that the market volume will grow to around 33.09 million metric tonnes worldwide in the year 2029. The global sodium silicate market size was valued at USD 6.25 billion in 2021 and the market is projected to grow to USD 8.19 billion by 2029, exhibiting a CAGR of 3.6 per cent during the forecast period. The market expansion can be attributed to the increasing demand for detergents worldwide and the growing use of sodium silicate in various applications, such as in water treatment, toothpaste, ceramics production, and the synthesis of silica gel, automotive sector, pulp & paper industry and the construction industry.
Presently, Nigeria expends over N20 billion on the importation of sodium silicate and silica gel annually for the production of detergents, rubber, food and beverage, paper and pulp, paints and coatings, plastics and inks. This is despite the fact that the raw material for the production of sodium silicate is abundant in Nigeria, either from the mineral (silica sand) or agro-resource (rice husk). Studies have indicated that the cost of sodium silicate production from silica sand in Nigeria is high and out of reach of many micro, small and medium-scale industrialists in Nigeria.
In recognition of this, the council, in collaboration with stakeholders is converting rice husk to serve as raw material for sodium silicate production.
According to the US Department of Agriculture, Nigeria’s rice production reached five million tonnes in 2022, slightly above the previous year. The US data show a significant increase in production between 2015 and 2017, then slowed before another jump in 2020 when production reached a high point of 5.04 million tonnes.
According to the United Nations Food and Agriculture Organisation (FAO) the land area under cultivation grew from about 3.1 million hectares in 2015 to 5.9 million hectares in 2018 and then dropped to 5.3 million hectares in 2020.
Nigeria produces 5.04 million tons of rice annually, resulting in 1.2 million tons of rice husk and 200,000 tonnes of rice husk ash. Currently, rice husk is mainly used for cattle feeding and partition board manufacturing, while rice husk ash is used in landfilling – both of which are environmentally hazardous. The lack of awareness of its potential, insufficient information about its industrial applications, socio-economic problems and inadequate processing technology are the reasons for this.
To address this issue, the director-general of the Raw Materials Research and Development Council (RMRDC), Prof. Hussaini Ibrahim said the council has developed a liquid sodium silicate pilot plant that uses rice husk ash as a silica source to produce sodium silicate using the hydrothermal process. This process is cost-effective, emits no dust or other gases, has low energy consumption and is suitable for small, medium and large-scale production.
The council,” he said, “is working with MAN and IPAN to independently analyze the product. They plan to commission a pilot production plant leading to commercialisation of the technology.
“The RMRDC is promoting private sector investment in the commercialisation of the technology and three investors have shown interest in establishing small-scale plants for producing sodium silicate from rice husk ash. When fully commercialised, the technology will save Nigeria more than N20 billion annually and promote increased profitability of rice farming, job creation and poverty eradication, in line with the Millennium Development Goals (MDGs) of the United Nations.”