A mineralizer composition for Pidgeon silicothermic process for smelting magnesium consists of fluorite and a boron-containing compound. Amounts of the fluorite and the boron-containing compound meet the following equation:

M.sub.fluo-original=(1−x)M.sub.fluo+(m)(x)M.sub.B,

where, M.sub.fluo-original is a mass of the fluorite required in a conventional Pidgeon silicothermic process in which no boron-containing compound is introduced to replace a fraction or all of the total fluorite, M.sub.fluo is a mass of the fluorite in the composition, M.sub.B is a mass of the boron-containing compound in the composition, 0.5≤x≤1, and 2≤m≤8. A Pidgeon silicothermic process for smelting magnesium is also provided, which employs the mineralizer composition. The composition and process of the disclosure enable reduction and even avoidance of dust pollution caused by fluorite-containing magnesium slag.

The present disclosure relates to a method of making core-shell and yolk-shell nanoparticles, and to electrodes comprising the same. The core-shell and yolk-shell nanoparticles and electrodes comprising them are suitable for use in electrochemical cells, such as fluoride shuttle batteries. The shell may protect the metal core from oxidation, including in an electrochemical cell. In some embodiments, an electrochemically active structure includes a dimensionally changeable active material forming a particle that expands or contracts upon reaction with or release of fluoride ions. One or more particles are at least partially surrounded with a fluoride-conducting encapsulant and optionally one or more voids are formed between the active material and the encapsulant using sacrificial layers or selective etching. The fluoride-conducting encapsulant may comprise one or more metals. When the electrochemically active structures are used in secondary batteries, the presence of voids can accommodate dimensional changes of the active material.

Disclosed are a slow-release inhibitor for high-magnesium sulfide mineral flotation and an application thereof, where the inhibitor is a nano colloidal particle of an alkaline earth fluoride such as CaF.sub.2 and BaF.sub.2 or a highly-reactive natural alkaline earth metal mineral powder. When applied to the flotation separation of a high-magnesium sulfide ore, the inhibitor can slowly release F ions to preferentially form a MgF.sub.2 layer on the magnesium-containing mineral surface, which provides a structure similar to MgF.sub.2 on a surface of oxidized gangue minerals such as magnesium oxide, changing surface electrical property of the magnesium-containing mineral, inhibiting heterogeneous coagulation of magnesium-containing minerals and sulfide ores due to electrostatic attraction and reducing entrainment, enveloping and agglomeration of gangue minerals to efficiently inhibit the flotation of oxidized gangue minerals such as magnesium oxide.

Disclosed are a slow-release inhibitor for high-magnesium sulfide mineral flotation and an application thereof, where the inhibitor is a nano colloidal particle of an alkaline earth fluoride such as CaF.sub.2 and BaF.sub.2 or a highly-reactive natural alkaline earth metal mineral powder. When applied to the flotation separation of a high-magnesium sulfide ore, the inhibitor can slowly release F ions to preferentially form a MgF.sub.2 layer on the magnesium-containing mineral surface, which provides a structure similar to MgF.sub.2 on a surface of oxidized gangue minerals such as magnesium oxide, changing surface electrical property of the magnesium-containing mineral, inhibiting heterogeneous coagulation of magnesium-containing minerals and sulfide ores due to electrostatic attraction and reducing entrainment, enveloping and agglomeration of gangue minerals to efficiently inhibit the flotation of oxidized gangue minerals such as magnesium oxide.

Provided is a positive electrode active material including a fluoride composite material including a composite of copper and a fluoride represented by the formula:

Ba.sub.xCa.sub.1-xF.sub.2

wherein x is 0.2 or more and 0.8 or less.

Provided is a positive electrode active material including a fluoride composite material including a composite of copper and a fluoride represented by the formula:

Ba.sub.xCa.sub.1-xF.sub.2

wherein x is 0.2 or more and 0.8 or less.

A method of removing fluoride ion from waste liquid is provided, which includes providing a calcium source and a plurality of ceramic particles to a waste liquid containing fluoride ion for forming a plurality of calcium fluoride layers wrapping the ceramic particles. The calcium fluoride layers are connected to form a calcium fluoride bulk. The ceramic particles are embedded in the calcium fluoride bulk. The ceramic particles and the calcium fluoride bulk have a weight ratio of 1:4 to 1:20.

A process for treating an ammonium fluorosulfate byproduct includes providing an ammonium fluorosulfate byproduct including primarily ammonium fluorosulfate and lesser amounts of fluorosulfonic acid and bis(fluorosulfonyl) imide, mixing the ammonium fluorosulfate byproduct with water, reacting the mixture of the ammonium fluorosulfate byproduct and the water at a hydrolysis reaction temperature to hydrolyze the ammonium fluorosulfate, the fluorosulfonic acid and the bis(fluorosulfonyl) imide to form ammonium bisulfate and aqueous hydrogen fluoride; and separating the ammonium bisulfate from the aqueous hydrogen fluoride.

A process for treating an ammonium fluorosulfate byproduct includes providing an ammonium fluorosulfate byproduct including primarily ammonium fluorosulfate and lesser amounts of fluorosulfonic acid and bis(fluorosulfonyl) imide, mixing the ammonium fluorosulfate byproduct with water, reacting the mixture of the ammonium fluorosulfate byproduct and the water at a hydrolysis reaction temperature to hydrolyze the ammonium fluorosulfate, the fluorosulfonic acid and the bis(fluorosulfonyl) imide to form ammonium bisulfate and aqueous hydrogen fluoride; and separating the ammonium bisulfate from the aqueous hydrogen fluoride.

Described herein is a process for converting halocarbons into inorganic salts comprising a halogen, the process comprising reacting a halocarbon with a metal salt to produce the inorganic salt comprising a halogen; wherein the metal salt comprises a metal and an electronegative element selected from nitrogen, oxygen, sulfur, chlorine, selenium, bromine and iodine, or a mixture thereof; wherein the halogen of the halocarbon is more electronegative than the electronegative element of the metal salt.