A method of improving metal leach kinetics and recovery during atmospheric or substantially atmospheric leaching of a metal sulfide is disclosed. In some embodiments, the method may comprise the step of processing a metal sulfide concentrate in a reductive activation circuit 220 that operates at a first redox potential, to produce a reductively-activated metal sulfide concentrate. The method may further comprise the step of subsequently processing the activated metal sulfide concentrate in an oxidative leach circuit 240 to extract metal values. In some disclosed embodiments, reductive activation steps and/or oxidative dissolution steps may employ mechano-chemical and/or physico-chemical processing of particles or agglomerates thereof. Reductive activation may be made prior to heap leaching or bio-leaching operations to improve metal extraction. Systems for practicing the aforementioned methods are also disclosed.

The present invention belongs to the technical field of soil heavy metal remediation, specifically discloses a method for preparing the iron-based biochar material, the iron-based biochar material prepared there from and a method for controlling the heavy metal pollution in soil using the iron-based biochar material. For the iron-based biochar material of the present invention, by using a method of high-temperature carbonization, a biomass is used as a raw material and an iron-containing compound is add in the process of preparing biochar, wherein iron is incorporated in a specific ratio, to form the iron-based biochar material with a special structure and function. The material has a simple preparation process, low cost and a short production period; the prepared iron-based biochar material has an unique effect on the arsenic-cadmium combined pollution soil remediation, can effectively reduce the bioavailability of arsenic and cadmium in the soil, significantly reduces the arsenic and cadmium contents in the agricultural products planted in the arsenic-cadmium combined pollution soil, and has no toxic and side effects on the crops, is safe to apply and can be applied to the control of arsenic-cadmium combined pollution soil in a large scale.

The present invention belongs to the technical field of soil heavy metal remediation, specifically discloses a method for preparing the iron-based biochar material, the iron-based biochar material prepared there from and a method for controlling the heavy metal pollution in soil using the iron-based biochar material. For the iron-based biochar material of the present invention, by using a method of high-temperature carbonization, a biomass is used as a raw material and an iron-containing compound is add in the process of preparing biochar, wherein iron is incorporated in a specific ratio, to form the iron-based biochar material with a special structure and function. The material has a simple preparation process, low cost and a short production period; the prepared iron-based biochar material has an unique effect on the arsenic-cadmium combined pollution soil remediation, can effectively reduce the bioavailability of arsenic and cadmium in the soil, significantly reduces the arsenic and cadmium contents in the agricultural products planted in the arsenic-cadmium combined pollution soil, and has no toxic and side effects on the crops, is safe to apply and can be applied to the control of arsenic-cadmium combined pollution soil in a large scale.

Process for enhanced metal recovery from, for example, metal-containing feedstock using liquid and/or supercritical fluid carbon dioxide and a source of oxidation. The oxidation agent can be free of complexing agent. The metal-containing feedstock can be a mineral such as a refractory mineral. The mineral can be an ore with high sulfide content or an ore rich in carbonaceous material. Waste can also be used as the metal-containing feedstock. The metal-containing feedstock can be used which is not subjected to ultrafine grinding. Relatively low temperatures and pressures can be used. The metal-containing feedstock can be fed into the reactor at a temperature below the critical temperature of the carbon dioxide, and an exotherm from the oxidation reaction can provide the supercritical temperature. The oxidant can be added to the reactor at a rate to maintain isothermal conditions in the reactor. Minimal amounts of water can be used as an extractive medium.

Process for enhanced metal recovery from, for example, metal-containing feedstock using liquid and/or supercritical fluid carbon dioxide and a source of oxidation. The oxidation agent can be free of complexing agent. The metal-containing feedstock can be a mineral such as a refractory mineral. The mineral can be an ore with high sulfide content or an ore rich in carbonaceous material. Waste can also be used as the metal-containing feedstock. The metal-containing feedstock can be used which is not subjected to ultrafine grinding. Relatively low temperatures and pressures can be used. The metal-containing feedstock can be fed into the reactor at a temperature below the critical temperature of the carbon dioxide, and an exotherm from the oxidation reaction can provide the supercritical temperature. The oxidant can be added to the reactor at a rate to maintain isothermal conditions in the reactor. Minimal amounts of water can be used as an extractive medium.

The invention relates to a method for the further processing of iron sulfate heptahydrate into iron sulfate monohydrate. An aqueous solution or suspension of iron sulfate heptahydrate is formed and heated in a pressure vessel to a temperature above its boiling temperature at atmospheric pressure and where solid iron sulfate monohydrate and a solution are formed. The solid iron sulfate monohydrate is separated from the solution and fed into a pressure vessel at a temperature above the boiling temperature of the solution at the pressure in the pressure vessel, which is lower than the pressure during separation.

The invention relates to a method for the further processing of iron sulfate heptahydrate into iron sulfate monohydrate. An aqueous solution or suspension of iron sulfate heptahydrate is formed and heated in a pressure vessel to a temperature above its boiling temperature at atmospheric pressure and where solid iron sulfate monohydrate and a solution are formed. The solid iron sulfate monohydrate is separated from the solution and fed into a pressure vessel at a temperature above the boiling temperature of the solution at the pressure in the pressure vessel, which is lower than the pressure during separation.

The present disclosure discloses a method for co-producing synthetical rutile and polymeric ferric sulfate with waste sulfuric acid, which includes the following steps of: S1, performing deep reduction on ilmenite to obtain reduced ilmenite with a metallization rate of 85% or more; S2, leaching the reduced ilmenite with waste sulfuric acid; S3, performing solid-liquid separation on a mixed solution after the leaching in step S2, and drying a solid to obtain synthetical rutile, wherein a filtrate is a ferrous sulfate solution; and then performing step S4 or S5 to obtain a polymeric ferric sulfate finished product. The waste sulfuric acid is adopted in the present disclosure to leach the reduced ilmenite to prepare the synthetical rutile, a novel waste acid recycling mode is formed

Aspects of the invention include a method of producing a cement material comprising step of: first reacting a calcium-bearing starting material with a first acid to produce an aqueous first calcium salt; second reacting the aqueous first calcium salt with a second acid to produce a solid second calcium salt; wherein the second acid is different from the first acid and the second calcium salt is different from the first calcium salt; and thermally treating the second calcium salt to produce a first cement material. Preferably, but not necessarily, during the second reacting step, reaction between the first calcium salt and the second acid regenerates the first acid.

The present invention provides: an assay method that uses a compound represented by formula (I) as a fluorescent probe molecule and that is for detecting the lipid peroxidation suppression activity of a test compound; an assay kit that uses the assay method; a screening method that uses the assay method; and a pharmaceutical composition that is for the treatment, etc. of diseases (such as age-related macular degeneration) that are induced by lipid peroxidation reactions.

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