Apparatus and method for ferrite formation and removal of heavy metal ions by ferrite co-precipitation from aqueous solutions

A method for continuous ferrite formation and removal of heavy metal ions by ferrite co-precipitation from aqueous solution, said method comprising:

• pumping untreated water having dissolved heavy metal ions into a first mixing tank;
• adding ferrous sulfate to said untreated water in said first mixing tank to form a solution in which the molar ratio of iron to heavy metal is greater than 3;
• agitating said solution in said first mixing tank;
• transporting said agitated solution from said first mixing tank into a reaction tank at a selected flow rate;
• agitating said solution in said reaction tank;
• distributing air through said solution in said reaction tank;
• adding a base to said solution in said reaction tank to adjust and control the pH of said solution to a value greater than 10;
• forming a ferrite slurry in said reaction tank;
• and
• transporting said ferrite slurry from said reaction tank into a settling tank where heavy metal ions and ferrite crystals co-precipitate to the bottom of said settling tank, wherein a flow rate of said ferrite slurry out of said reaction tank is substantially the same as the flow rate of solution into said reaction tank.

An assembly for ferrite formation and removal of heavy metal ions by ferrite co-precipitation from aqueous solution, said assembly including:

• means for pumping untreated water having dissolved heavy metal ions into a first mixing tank;
• means for adding ferrous sulfate to said untreated water in said first mixing tank to form a solution in which the molar ratio of iron to heavy metal is greater than 3;
• means for agitating said solution in said first mixing tank;
• means for transporting said agitated solution from said first mixing tank into a reaction tank at a selected flow rate;
• means for agitating said solution in said reaction tank;
• means for distributing air through said solution in said reaction tank;
• means for adding a base to said solution in said reaction tank to adjust and control the pH of said solution to a value greater than 10;
• means for forming a ferrite slurry in said reaction tank;
• and
• means for transporting said ferrite slurry from said reaction tank into a settling tank where heavy metal ions and ferrite crystals co-precipitate to the bottom of said settling tank, wherein a flow rate of said ferrite slurry out of said reaction tank is substantially the same as the flow rate of solution into said reaction tank.

An assembly for ferrite formation and removal of heavy metal ions by ferrite co-precipitation from aqueous solution, said assembly including:

• an untreated water tank;
• a first mixing tank in flow communication with said first untreated water tank;
• a first feeder assembly in material flow communication with said first mixing tank;
• a first agitator assembly having a first agitator extending into the interior of said first mixing tank;
• a neutralization tank in flow communication with said first mixing tank;
• a second agitator assembly having a second agitator extending into the interior of said neutralization tank;
• an oxidation tank in flow communication with said neutralization tank;
• an air supply conduit extending into said oxidation tank;
• a first pH sensor located in said neutralization tank;
• a second pH sensor located in said oxidation tank;
• a pH control assembly in electronic communication with said first and second pH sensors and wherein said pH control assembly controls the pH of water in said neutralization tank and in said oxidation tank to a desired value;
• a settling tank in flow communication with said oxidation tank;
• a polishing tank in flow communication with said settling tank;
• and
• a magnetic separation assembly connected to said settling tank to remove magnetically susceptible ferrite crystals from said settling tank.

A method for continuous ferrite formation and removal of heavy metal ions from an aqueous solution by ferrite co-precipitation, said method comprising:

• pumping untreated water having dissolved heavy metal ions into a first mixing tank;
• adding ferrous sulfate to said untreated water in said first mixing tank to form a solution in which the molar ratio of iron to heavy metal is greater than 3;
• agitating said solution in said first mixing tank;
• transporting the agitated solution from said first mixing tank into a neutralization tank at a first flow rate;
• agitating said solution in said neutralization tank;
• adding a base to said solution in said neutralization tank to adjust and control the pH of said solution to a value greater than 10;
• transporting said agitated solution from said neutralization tank into an oxidation tank at a second flow rate;
• distributing air through said solution in said oxidation tank;
• agitating said solution in said oxidation tank;
• adding a base to said solution in said oxidation tank to control the pH of said solution to a value greater than 10;
• forming a ferrite slurry in said oxidation tank;
• and
• transporting said ferrite slurry from said oxidation tank into a settling tank at a third flow rate where heavy metal ions and ferrite crystals co-precipitate to the bottom of said settling tank, wherein said first flow rate, said second flow rate and said third flow rate are substantially the same.

An assembly for ferrite formation and removal of heavy metal ions by ferrite co-precipitation from aqueous solution, said assembly including:

• means for pumping untreated water having dissolved heavy metal ions into a first mixing tank;
• means for adding ferrous sulfate to said untreated water in said first mixing tank to form a solution in which the molar ratio of iron to heavy metal is greater than 3;
• means for agitating said solution in said first mixing tank;
• means for transporting the agitated solution from said first mixing tank into a neutralization tank at a first flow rate;
• means for agitating said solution in said neutralization tank;
• means for adding a base to said solution in said neutralization tank to adjust and control the pH of said solution to a value greater than 10;
• means for transporting said agitated solution from said neutralization tank into an oxidation tank at a second flow rate;
• means for distributing air through said solution in said oxidation tank;
• means for agitating said solution in said oxidation tank;
• means for adding a base to said solution in said oxidation tank to adjust and control the pH of said solution to a value greater than 10;
• means for forming a ferrite slurry in said oxidation tank;
• and
• means for transporting said ferrite slurry from said oxidation tank into a settling tank at a third flow rate where heavy metal ions and ferrite crystals co-precipitate to the bottom of said settling tank, wherein said first flow rate, said second flow rate and said third flow rate are substantially the same.