Hydrometallurgical method for recovery of zinc in sulphuric medium starting from sulphidic zinc concentrates with high iron content

A hydrometallurgical method for recovering zinc in sulphuric media from sulphidic zinc concentrates with high iron content characterized in that a zinc concentrate is subjected to the following steps, all of which except step (a), take place at atmospheric pressure:

• a. roasting of at least part of the zinc concentrate;
• b. neutral leaching where zinc oxide is dissolved;
• c. acid leaching where zinc ferrites are leached by means of sulphuric acid in the form of spent electrolyte and concentrated sulphuric acid, generating a resulting solution rich in zinc and iron that contains between 10 and 35 g/l of Fe+++ and between 10 and 70 g/l of sulphuric acidity, and a residue wherein are concentrated the lead, silver and gold contained in the concentrates;
• d. reducing the Fe+++ contained in the solution resulting from step (c) to Fe++ by adding zinc concentrate obtained during step (f) at the required rate to obtain a final Fe++ concentration that allows working during step (f) with a final acidity between pH 1.5 and 10 g/l without using any neutralizing agent other than the products necessary for the reactions characteristic of the step (f) to take place;
• e. neutralizing the acidity of the solution resulting from step (d) with calcine, generating a final solution with a pH between 3.8 and 5.2 and a final Fe++ concentration such that allows working during step (f) at a final acidity between pH 1.5 and 10 g/l without using any neutralizing agent other than the products necessary for the reactions characteristic of the step (f) to take place;
• f. oxidizing iron and precipitating jarosite from the solution resulting from step (e), free of contaminating solids, by injecting oxygen or oxygen-enriched air and adding an alkali or a Na+ o NH4+ salt, resulting in a final solution having an acidity between pH 1.5 and 10 g/l.

A hydrometallurgical method for recovering zinc in sulphuric media from sulphidic zinc concentrates with high iron content characterized in that a zinc concentrate is subjected to the following steps, all of which except step (a), take place at atmospheric pressure:

• a. roasting of at least part of the zinc concentrate;
• b. neutral leaching where zinc oxide is dissolved;
• c. acid leaching where zinc ferrites are leached by means of sulphuric acid in the form of spent electrolyte and concentrated sulphuric acid, generating a resulting solution rich in zinc and iron that contains between 10 and 35 g/l of Fe+++ and between 10 and 70 g/l of sulphuric acidity, and a residue wherein are concentrated the lead, silver and gold contained in the concentrates;
• d. reducing the Fe+++ contained in the solution resulting from step (c) to Fe++ by adding zinc concentrate;
• e. meutralizing the acidity of the solution resulting from step (d) with calcine, and diluting it with a zinc sulphate solution resulting from step (f) at the required rate to obtain a final solution with a pH between 3.8 and 5.2 and a final Fe++ concentration such that allows working during step (f) at a final acidity between pH 1.5 and 10 g/l without using any neutralizing agent other than the products necessary for the reactions characteristic of the step (f) to take place;
• f. oxidizing iron and precipitating jarosite from the solution resulting from step (e), free of contaminating solids, by injecting oxygen or oxygen-enriched air and adding an alkali or a Na+ o NH4+ salt, resulting in a final solution having an acidity between pH 1.5 and 10 g/l.

A hydrometallurgical method for recovering zinc in sulphuric media from sulphidic zinc concentrates with high iron content characterized in that a zinc concentrate is subjected to the following steps, all of which except step (a), take place at atmospheric pressure:

• a. roasting of at least part of the zinc concentrate;
• b. neutral leaching where zinc oxide is dissolved;
• c. acid leaching where zinc ferrites are leached by means of sulphuric acid in the form of spent electrolyte and concentrated sulphuric acid, generating a resulting solution rich in zinc and iron that contains between 10 and 35 g/l of Fe+++ and between 10 and 70 g/l of sulphuric acidity, and a residue wherein are concentrated the lead, silver and gold contained in the concentrates;
• d. reducing the Fe+++ contained in the solution resulting from step (c) to Fe++ by adding zinc concentrate;
• e. neutralizing the acidity of the solution resulting from step (d) with calcine.
• f. oxidizing iron and precipitating jarosite from the solution resulting from step (e), free of polluting solids, by injecting oxygen or oxygen-enriched air and adding an alkali or a Na+ o NH4+ salt, and diluting it with zinc sulphate resulting from step (b) at the required rate to obtain a final solution with an acidity between pH 1.5 and 10 g/l without using any neutralizing agent other than the products necessary for the reactions characteristic of this step.

A hydrometallurgical method for recovering zinc in sulphuric media from sulphidic zinc concentrates with high iron content characterized in that a zinc concentrate is subjected to the following steps, all of which except step (a), take place at atmospheric pressure:

• a. roasting of at least part of the zinc concentrate;
• b. neutral leaching where zinc oxide is dissolved;
• c. acid leaching where zinc ferrites are leached by means of sulphuric acid in the form of spent electrolyte and concentrated sulphuric acid, generating a resulting solution rich in zinc and iron that contains between 10 and 35 g/l of Fe+++ and between 10 and 70 g/l of sulphuric acidity, and a residue wherein are concentrated the lead, silver and gold contained in the concentrates;
• d. reducing the Fe+++ contained in the solution resulting from step (c) to Fe++ by adding zinc concentrate;
• e. neutralizing the acidity of the solution resulting from step (d) with calcine;
• f. oxidizing iron and precipitating jarosite from the solution resulting from step (e), free of contaminating solids, by injecting oxygen or oxygen-enriched air and adding an alkali or a Na+ o NH4+ salt, and diluting it with zinc sulphate resulting from the same step (f) at the required rate to obtain a final solution with an acidity between pH 1.5 and 10 g/l without using any neutralizing agent other than the products necessary for the reactions characteristic of this step.