Calcium carbonate reuse in local agriculture in Portugal

Reuse of calcium carbonate boosts efficiency and sustainability in Lisbon

At our Lisbon Refinery in Portugal, innovation and sustainability go hand in hand. One of our recent achievements involves upcycling what was once considered a waste, into a valuable byproduct.

Carbonatation is a step in the sugar refining process where impurities are removed from raw sugar. This process involves bubbling carbon dioxide gas through heated and limed sugar melt, forming a precipitate that is filtered to remove impurities. The resulting material, known as press mud, is rich in calcium carbonate, making it suitable for soil pH correction in agriculture.

Calcium carbonate improves soil fertility by raising pH levels and offers a more natural alternative to synthetic fertiliser for land restoration. Its trace sugar content and eco-friendly composition makes it a valuable resource for sustainable agriculture.

While press mud has potential as a fertiliser and soil enhancer, finding consistent buyers had been challenging due to market size and logistics costs. But, two years ago, we forged a partnership with a gardening company in Portugal which recognised the byproduct’s value. By providing the material at no cost to our partner, and leveraging their logistics capabilities, the partnership has allowed us to reduce disposal costs significantly and reduce our environmental impact.