A process for direct reduction of iron ore in a solid state is disclosed. The process operates under anoxic conditions with biomass as a reductant and with electromagnetic energy as a source of heat.

A method of recovering iron from a zinc sulfate solution according to an embodiment of the present disclosure is associated with recovering iron from a zinc sulfate solution produced by a leaching process in which zinc ore is dissolved in sulfuric acid. The method comprises a conditioning process including a step of reducing a conditioning process input solution, which is the zinc sulfate solution, and an iron precipitation process for recovering iron as hematite, including a step of pressurizing and oxidizing an iron precipitation process input solution discharged from the conditioning process. The iron precipitation process is performed at a temperature ranging from 135 C. to 150 C. and a pressure ranging from 5 barg to 10 barg.

The present invention discloses a method of using a waste silicon slurry. The method includes the steps of: (A) obtaining a waste silicon slurry containing a cutting oil and a metal; (B) treating the waste silicon slurry with a first reagent for reacting with the cutting oil; (C) treating the waste silicon slurry with a second reagent for reacting with the metal; (D) separating products resulting from step (B) and step (C) to obtain a solid portion; and (E) treating the solid portion with a third reagent to obtain products, including silicates and hydrogen gas.

The present invention discloses a method of using a waste silicon slurry. The method includes the steps of: (A) obtaining a waste silicon slurry containing a cutting oil and a metal; (B) treating the waste silicon slurry with a first reagent for reacting with the cutting oil; (C) treating the waste silicon slurry with a second reagent for reacting with the metal; (D) separating products resulting from step (B) and step (C) to obtain a solid portion; and (E) treating the solid portion with a third reagent to obtain products, including silicates and hydrogen gas.

The present invention relates to a method and a process of preparing precipitated calcium carbonate of high purity by extracting calcium ion contained in an alkali ion-containing inorganic material such as mineral, steelmaking slag and waste concrete with the use of an acidic aqueous solution, separating other metal ions from the extracted solution, preparing an alkaline earth metal hydroxide using an alkaline aqueous solution and then contacting the same with carbon dioxide.

The present invention relates to a method and a process of preparing precipitated calcium carbonate of high purity by extracting calcium ion contained in an alkali ion-containing inorganic material such as mineral, steelmaking slag and waste concrete with the use of an acidic aqueous solution, separating other metal ions from the extracted solution, preparing an alkaline earth metal hydroxide using an alkaline aqueous solution and then contacting the same with carbon dioxide.

The present invention relates to a method for converting and separating vanadium, titanium, and iron from the vanadium-titanium-iron concentrate in one step, which includes the steps as below. (1) The vanadium-titanium-iron concentrate is mixed and roasted together with addition agent and reducing agent, and thereby vanadium-containing pig iron and vanadium enriched slag are obtained. (2) The vanadium titanium enriched slag is leached in water and filtered, and thereby vanadium-containing solution and titanium slag are obtained. The technical features of the present invention are as below. By the new process of sodium reduction coupling, a new system of low-temperature smelting multiphase reaction separation is constructed. The reduction of iron, sodiumizing of vanadium, and the melting separation process of the vanadium titanium enriched slag and the iron are achieved in one step. Three products, i.e., the vanadium-containing pig iron, the vanadium-containing solution, and the titanium slag are produced.

The present invention relates to a method for converting and separating vanadium, titanium, and iron from the vanadium-titanium-iron concentrate in one step, which includes the steps as below. (1) The vanadium-titanium-iron concentrate is mixed and roasted together with addition agent and reducing agent, and thereby vanadium-containing pig iron and vanadium enriched slag are obtained. (2) The vanadium titanium enriched slag is leached in water and filtered, and thereby vanadium-containing solution and titanium slag are obtained. The technical features of the present invention are as below. By the new process of sodium reduction coupling, a new system of low-temperature smelting multiphase reaction separation is constructed. The reduction of iron, sodiumizing of vanadium, and the melting separation process of the vanadium titanium enriched slag and the iron are achieved in one step. Three products, i.e., the vanadium-containing pig iron, the vanadium-containing solution, and the titanium slag are produced.

The present disclosure relates to methods for enhanced demetalyzation of an ultrahard material, such as polycrystalline diamond (PCD) or cubic boron nitride (CBN), using a thiourea solution. The thiourea solution may contain thiourea and an acid, such as a Bronstead acid suitable for leaching. The thiourea may contain thiourea or a substituted thiourea, including tautomers thereof. The ultrahard material may be exposed to the thiourea solution for a time and under conditions sufficient to remove at least a desired amount of a metal, such as a catalyst used during formation of the PCD or CBN, from at least a portion of the ultrahard material.

A bioleaching and solvent extraction process with selective recovery of copper and zinc from polymetallic sulphide concentrates is described, comprising a bioleaching and ferric ion reducing process and a copper and zinc solvent extraction process. The bioleaching and ferric ion reducing process comprises a concentrates pulp conditioning step; a bioleaching step, wherein once the pulp is conditioned it is subjected to a bioleaching process using a plurality of bioreactors of the stirred-tank type with an air injection and diffusion system, which allows handling of a pulp density higher than 15%; a step of solid separation from a solution rich in metallic ions from the bioleaching step; and, a ferric ion reduction step, wherein the pulp from the previous step is subjected to a transformation step of ferric ions into ferrous ions. The solvent extraction step comprises a copper solvent extraction and electrolysis step; an arsenic control step, wherein arsenic is controlled in the solution once copper has been extracted from it; and, a zinc solvent extraction and electrolysis step, which uses a phosphinic acid-based zinc extraction dissolution.