Simple recycling of biowaste eggshells to various calcium phosphates for specific industries

Abstract

Egg consumption is very high throughout the world and with it comes enormous amount of waste eggshells. To reduce and utilize these wastes, eggshell wastes were simply transformed to low- or high-purity calcium carbonate grades by washing, crushing, and drying to use as raw materials for producing highly valuable calcium phosphate products. Low-purity calcium carbonate grade was used to prepare triple superphosphate for using in fertilizer industry, whereas high-purity calcium carbonate grade was used to produce dicalcium phosphate dihydrate, monocalcium phosphate monohydrate, and tricalcium phosphate for using in mineral feed and food additive industries. All calcium phosphate samples obtained by simple, rapid, cheap, and environmentally safe method using eggshells and phosphoric acid were identified and their structural phases and impurities were determined by XRF, XRD and FTIR techniques. Thermal behaviors of raw materials and the prepared calcium phosphates excepted tricalcium phosphate were investigated by TG/DTG techniques. The methodologies described here will be useful to manage eggshells by converting them to highly valuable products, which can solve eggshell wastes problem from industries and communities. This finding supports the viewpoint of zero waste operation to produce value-added products for obtaining sustainable development, which may be selected as an alternative way for material recycling and waste management in the future.

Waste Eggshells as a Natural Filler for the Poly(Vinyl Chloride) Composites

“…The remaining approx. 4% of the shell mass consists of polysaccharides, various collagens, fatty acids, and water [ 5 , 6 ]. The eggshell microstructure is unique.…”

Synthesis of gypsum fertilizer from waste eggshells for a sustainable environment

“…Thus, the gypsum was produced in single phase compound.The crystallite size was calculated employing the Scherrer's equation (equation 6) and the obtained value was 123 nm. The lattice parameters were estimated form the equation 9 the measured values were a=6.24, b=15.18, and c= 5.65 which were very much close to the standard database (Card no: #00-033-0311) of gypsum monoclinic crystal structure having space group C2/c(15). The dislocation and microstrain were computed with the aid of equations 9 and 10 and the generated values are 0.0654 and 0.1583, respectively.…”

“…Investigations on the application of eggshells in synthesizing hydroxyapatite, tricalcium phosphate, and various bone like substance have been well practiced in many previous studies [13,14]. Additionally, synthesis of other industrially important materials such as monocalcium/ dicalcium/tricalcium phosphates have also been reported [15]. The use of eggshells in calcium sulphate form is another way of waste utilization.…”

Minerals Composition and Characterization of the Hatchery Eggshell Waste Treated with Different Preparation Methods

“…Nurlaela et al (2014) On the other hand, the decrease in calcium content increased the phosphorus (P) T4 content (Table 2). In addition to organic materials, eggshells contain inorganics such as calcium carbonate, magnesium carbonate, calcium phosphate, and magnesium phosphate (Laohavisuti et al, 2021). T4 eggshells were treated using acid.…”