BigPatents India

A method of manufacture of building blocks from phosphogypsum, obtained as a by product in the preparation of phosphoric acid by contacting sulphuric acid willi rock phosphate, comprising the steps of thoroughly mixing 25% -to 50 % by volume of the said phosphogypsum, manually or under power, with upto 75% by volume of coarse aggregate of various sizes, 0 to 40% by volume of granite quarry dust and upto 10% by volume of cement, moulding the mix in block moulds and allowing the same to set; demoulding the set moulded blocks before drying the same; and moistening the dried blocks thereafter with water to obtain the fmished blocks and product of cement phosphogypsum block or building block.