A method for recycling spent carbon cathode of aluminum electrolysis includes the following steps: (1) crushing and sieving spent carbon cathode, to obtain carbon particles; (2) mixing the carbon particles with a sulfuric acid solution, to obtain a slurry A, and then performing pressure leaching, to obtain a slurry B; (3) evaporating and concentrating the slurry B until a mass percentage of water is lower than 8%, to obtain a slurry C; (4) adding concentrated sulfuric acid to the slurry C to obtain a slurry D, then roasting the slurry D at 150-300° C. for 0.5-10 h, and then roasting at 300-600° C. for 0.5-8 h, to obtain the roasted carbon; and calcining the roasted carbon at a high temperature, to obtain the purified carbon, or mixing the roasted carbon with a leaching agent, and performing leaching, filtering, and washing, to obtain the purified carbon.

A method for recycling spent carbon cathode of aluminum electrolysis includes the following steps: (1) crushing and sieving spent carbon cathode, to obtain carbon particles; (2) mixing the carbon particles with a sulfuric acid solution, to obtain a slurry A, and then performing pressure leaching, to obtain a slurry B; (3) evaporating and concentrating the slurry B until a mass percentage of water is lower than 8%, to obtain a slurry C; (4) adding concentrated sulfuric acid to the slurry C to obtain a slurry D, then roasting the slurry D at 150-300° C. for 0.5-10 h, and then roasting at 300-600° C. for 0.5-8 h, to obtain the roasted carbon; and calcining the roasted carbon at a high temperature, to obtain the purified carbon, or mixing the roasted carbon with a leaching agent, and performing leaching, filtering, and washing, to obtain the purified carbon.

A method for the processing of potassium containing materials comprises: (i) Separation of a potassium containing mineral from gangue minerals; (ii) Acid leaching whereby substantially all potassium, iron, aluminium and magnesium is solubilised and mixed potassium/iron double salt formed; (iii) Selectively crystallising the mixed potassium/iron double salt formed in the leach step (ii); (iv) Second separation to separate the mixed potassium/iron double salt formed in step (iii); (v) Thermal decomposition to produce an iron oxide, a potassium salt and one or more phosphates; (vi) Leaching the product of the thermal decomposition; (vii) Third separation to separate the iron oxide and phosphate from the potassium salt; (viii) Recovering the potassium salt by crystallisation; (ix) Separating the iron oxide and phosphate of step (vii) by leaching and subsequent solid liquid separation; and (x) Precipitating phosphate from liquor produced in step (ix) through the addition of a base.

The invention relates to processes for the extraction of products from titanium-bearing materials or a composition produced in a process for the production of titanium dioxide, and more particularly, although not exclusively, extracting titanium dioxide and/or one or more other products from iron making slag.

The invention relates to processes for the extraction of products from titanium-bearing materials or a composition produced in a process for the production of titanium dioxide, and more particularly, although not exclusively, extracting titanium dioxide and/or one or more other products from iron making slag.

A negative electrode active material for a secondary battery, including lithium titanium-based composite particles comprising: a lithium titanium oxide represented by Li.sub.xTi.sub.yO.sub.z, wherein x, y and z satisfy 0.1≤x≤4, 1≤y≤5 and 2≤z≤12; Zr doped into the lithium titanium oxide; and an aluminum and sulfur containing compound coated on a surface of the lithium titanium oxide. The lithium titanium-based composite particles include at least one of primary particles or secondary particles formed by agglomeration of the primary particles, and an average particle size of the primary particles of the lithium titanium-based composite particles is in a range of 550 nm to 1.1 μm.

A negative electrode active material for a secondary battery, including lithium titanium-based composite particles comprising: a lithium titanium oxide represented by Li.sub.xTi.sub.yO.sub.z, wherein x, y and z satisfy 0.1≤x≤4, 1≤y≤5 and 2≤z≤12; Zr doped into the lithium titanium oxide; and an aluminum and sulfur containing compound coated on a surface of the lithium titanium oxide. The lithium titanium-based composite particles include at least one of primary particles or secondary particles formed by agglomeration of the primary particles, and an average particle size of the primary particles of the lithium titanium-based composite particles is in a range of 550 nm to 1.1 μm.

A process for the recovery of lithium hydroxide from lithium sulfate containing solutions, the process characterised by the following method steps: precipitating ettringite from a lithium sulfate containing solution in a primary ettringite precipitation step (100); subsequent recovery of a liquor (7, 11) containing lithium hydroxide; and producing a lithium hydroxide monohydrate product (22) from the lithium hydroxide liquor (7, 11).

A method of processing a non-virgin sulfuric acid solution for the preparation of aluminum sulfate comprises the steps of combining a sulfuric acid solution having less than about 90% sulfuric acid with a water solution to form a mixed solution of no less than about 10% sulfuric acid. An alumina-containing compound such as aluminum hydroxide or aluminum bauxite is then added to the mixed solution to form aluminum sulfate.

A method of processing a non-virgin sulfuric acid solution for the preparation of aluminum sulfate comprises the steps of combining a sulfuric acid solution having less than about 90% sulfuric acid with a water solution to form a mixed solution of no less than about 10% sulfuric acid. An alumina-containing compound such as aluminum hydroxide or aluminum bauxite is then added to the mixed solution to form aluminum sulfate.