Patent ID: 11873233
Assignee: KING FAISAL UNIVERSITY
Field: Chemical engineering (Chemistry)
Classification: CPC C  B | IPC B  C

Claim 19:
20. A method of preparing magnetite nanoparticles and akaganéite nanoparticles, the method comprising:
suspending a steel slag powder in distilled water to obtain a steel slag suspension;
adding HCl to the steel slag suspension under vigorous stirring to obtain an acidified steel slag suspension;
slowly adding dropwise a diluted hydrogen peroxide having a concentration of about 5% v/v in water to a first sample of the acidified steel slag suspension to obtain a sample A;
rapidly adding under vigorous stirring a concentrated hydrogen peroxide having a concentration of about 20% v/v in water to a second sample of the acidified steel slag suspension to obtain a sample B;
separating dark gray precipitates from sample A by centrifugation to obtain a precipitated sample A and a sample A solution;
separating dark gray precipitates from sample B by centrifugation to obtain a precipitated sample B and a sample B solution;
separating by magnetic decantation a magnetite rich solid from the precipitated sample B to obtain the magnetite nanoparticles;
adding dropwise and under magnetic stirring a concentrated ammonia having a concentration of about 25% v/v in water to the sample A solution until the sample A solution reaches a pH of 6 to obtain a neutralized sample A;
adding dropwise and under magnetic stirring a concentrated ammonia having a concentration of about 25% v/v in water to the sample B solution until the sample B solution reaches a pH of 6 to obtain a neutralized sample B; and
separating brown solids by centrifugation from the neutralized sample A and the neutralized sample B to obtain first and second akaganéite nanoparticles, respectively.