Where can I find a list of Bangladeshi fertiliser/fertilizer manufacturing companies?
Search in Orbis and Capital IQ. Both provide listings for private and public companies worldwide along with financial details. Neither includes very small businesses and coverage varies by country and level of business reporting regulations in each country. Searching in both could give you a broader set of results if you're searching for smaller private companies.
For Orbis: Select Location. Then Activities & Industry-->Industry Classifications-->search for fertiliser and select industries from there. Add other criteria such as financial, ownership, etc. View Results.
For Capital IQ: Select Screening tab-->Companies and set up your screen by geography, industry, ownership etc. Search for fertilizer to find industries.
Be sure to use the US spelling for industries in Capital IQ and the UK spelling for Orbis. (Capital IQ is a US database and Orbis is from the EU.)