Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
150 words
A method of treating sulphidic mattes containing between 5% and 60% iron, between 15% and 40% sulphur together with soluble non-ferrous metals or metal compounds selected from the group consisting of copper, cobalt, nickel and zinc, said method comprising contacting and leaching finely ground sulphidic matte with a leach solution having at least the stoichimetric quantity of available sulphate present therein which is required for dissolving all soluble non-ferrous metals in the matte as sulphates, the leaching being carried out at a temperature of between 70° to 120° C. and with an oxygen partial pressure from 50 kPa to 1,000 kPa, the leaching being continued for a time sufficient to enable iron, which initially dissolves in the leach liquor, to precipitate out as a filterable iron precipitate and be displaced by soluble non-ferrous metals until such time as substantially all soluble sulpur is liberated in the form of elemental sulphur.
Claim 2
Independent Claim
150 words
A method of treating sulphidic mattes containing between 5% and 60% iron, between 15% and 40% sulphur together with soluble non-ferrous metals or metal compounds selected from the group consisting of copper, cobalt, nickel and zinc, said method comprising contacting and leaching finely ground sulphidic matte with a leach solution having at least the stoichimetric quantity of available sulphate present therein which is required for dissolving all soluble non-ferrous metals in the matte as sulphates, the leaching being carried out at a temperature of between 70° to 120° C. and with an oxygen partial pressure from 50 kPa to 1,000 kPa, the leaching being continued for a time sufficient to enable iron, which initially dissolves in the leach liquor, to precipitate out as a filterable iron precipitate and be displaced by soluble non-ferrous metals until such time as substantially all soluble sulpur is liberated in the form of elemental sulphur.
Claim 3
Dependent Claim
73 words
A method as recited in claim 1 in which the amount of available sulphate present in the leaching solution is chosen to provide sulphate in the sulphuric acid form at a concentration of between 2.5 and 15 grams per liter after substantially all the soluble non-ferrous metals have been dissolved in which case between 1.0 and 5.0 grams per liter dissolved iron will be in solution and the filterable precipitate is predominantly goethite.
Claim 4
Dependent Claim
19 words
A method as claimed in claim 1 in which the oxygen partial pressure is between 200 and 500 kPa.
Claim 5
Dependent Claim
22 words
A method as claimed in claim 1 in which the temperature of the leach solution is from 90° C. to 100° C.
Claim 6
Dependent Claim
26 words
A method as claimed in claim 1 in which the sulphidic material contains, in addition to iron and sulphur appreciable quantities of copper, cobalt and nickel.
Claim 7
Dependent Claim
29 words
A method as claimed in claim 1 in which the sulphidic material contains platinum group metals, gold and silver which are insoluble and thus remain in the leach residue.
Claim 8
Dependent Claim
22 words
A method as claimed in claim 1 in which required insoluble metals or sulphur are separated and recovered from the leach residue.
Claim 9
Dependent Claim
26 words
A method as claimed in claim 1 wherein the residual iron in solution at the end of the leaching stage is removed by oxidation and neutralization.
Claim 10
Dependent Claim
19 words
A method as claimed in claim 1 wherein the dissolved non-ferrous metals are separated from each other and recovered.
Claim 11
Independent Claim
163 words
A method of treating sulphidic mattes containing between 5% wt. to 60% wt. iron, 15% wt. to 40% wt. sulphur together with copper, cobalt, nickel and optionally other soluble non-ferrous metals or metal compounds including zinc, said method simultaneously separating iron and sulphur from the matte and extracting the soluble non-ferrous metals therefrom and comprising the steps of: (1) contacting and leaching finely ground sulphidic matte with a sulphuric acid leach solution having at least the stoichometric quantity of available sulphate present therein required to dissolve all soluble non-ferrous metals present in the matte as sulphates, said leaching conducted at from 70° C. to 120° C. with an oxygen partial pressure from 50 kPa to 1,000 kPa; and (2) continuing said leaching until (i) the iron, which initially dissolves in the leach liquor, is precipitated out as a filterable iron precipitate and is displaced by the soluble non-ferrous metals, and (ii) substantially all soluble sulphur is liberated in the form of elemental sulphur.
Claim 12
Independent Claim
163 words
A method of treating sulphidic mattes containing between 5% wt. to 60% wt. iron, 15% wt. to 40% wt. sulphur together with copper, cobalt, nickel and optionally other soluble non-ferrous metals or metal compounds including zinc, said method simultaneously separating iron and sulphur from the matte and extracting the soluble non-ferrous metals therefrom and comprising the steps of: (1) contacting and leaching finely ground sulphidic matte with a sulphuric acid leach solution having at least the stoichometric quantity of available sulphate present therein required to dissolve all soluble non-ferrous metals present in the matte as sulphates, said leaching conducted at from 70° C. to 120° C. with an oxygen partial pressure from 50 kPa to 1,000 kPa; and (2) continuing said leaching until (i) the iron, which initially dissolves in the leach liquor, is precipitated out as a filterable iron precipitate and is displaced by the soluble non-ferrous metals, and (ii) substantially all soluble sulphur is liberated in the form of elemental sulphur.