Wow! I only knew it now. You have a productive research project. We can also use egg shells plus vinegar in making calcium phosphate intended for gardening. After fermentation, you spray it to the flowers of the plants like eggplant and vines (squash, cucumber, gourds, etc.) to make it hold and become a vegetable. Well, good job to you guys! Congrats.
thankyouu so much @cup-bearer and thankyouu for telling that eggshells plus vinegar can use for gardening,i'll try it if I have many time🥰