The present invention relates to a method for removing cesium in a clay mineral using hydrogen peroxide. According to the present invention, cesium in a clay mineral is removed using hydrogen peroxide, which serves to induce interlayer expansion of the clay mineral to allow a cation to easily enter an interlayer of the clay mineral, and thus cesium desorption efficiency can be further improved. Also, the method according to the present invention can be efficiently used to restore soil in residential areas widely contaminated with a radionuclide when a major accident such as Fukushima nuclear accident occurs as well as various sites of atomic energy facilities contaminated with a radionuclide. Also, since radiation-contaminated soil is treated with only hydrogen peroxide and cations, secondary environmental pollution caused by wastes can be significantly reduce and the waste disposing cost can also be saved.

The invention discloses a method of solution mining trona by injecting an aqueous solvent into an underground cavity comprising trona to dissolve trona in the aqueous solution and removing the aqueous solution from the cavity at about the WTN triple point (the temperature at which solid phase wegscheiderite, trona, and nahcolite can co-exist in an aqueous solution). Alkaline values from the removed aqueous solution are recovered to produce a barren liquor. The method further includes either (i) treating the barren liquor to produce an aqueous solvent or (ii) treating injected aqueous solvent to reduce clogging at the trona dissolution surface caused by supersaturation of sodium bicarbonate, and precipitation of nahcolite and wegscheiderite as the aqueous solution in the cavity approaches saturation of both dissolved sodium bicarbonate and sodium carbonate.

This invention relates to treated geothermal brine compositions containing reduced concentrations of iron, silica, and manganese compared to the untreated brines. Exemplary compositions contain a concentration of manganese less than 10 mg/kg, a concentration of silica ranging from less than 10 mg/kg, and a concentration of iron less than 10 mg/kg, and the treated geothermal brine is derived from a Salton Sea geothermal reservoir.

This invention relates to treated geothermal brine compositions containing reduced concentrations of iron, silica, and manganese compared to the untreated brines. Exemplary compositions contain a concentration of manganese less than 10 mg/kg, a concentration of silica ranging from less than 10 mg/kg, and a concentration of iron less than 10 mg/kg, and the treated geothermal brine is derived from a Salton Sea geothermal reservoir.

Some variations provide an alkali metal or alkaline earth metal vapor cell with a solid ionic conductor and intercalable-compound electrodes. The intercalable-compound electrodes are used as efficient sources and/or as sinks for alkali metal or alkaline earth metal atoms, thus enabling electrical control over metal atom content in the vapor cell. Some variations provide a vapor-cell system comprising: a vapor-cell region configured to allow a vapor-cell optical path into a vapor-cell vapor phase; a first electrode; a second electrode electrically isolated from the first electrode, wherein the second electrode contains an intercalable compound intercalated by an element selected from Rb, Cs, Na, K, or Sr; and an ion-conducting layer between the first electrode and the second electrode. The ion-conducting layer is ionically conductive for at least one ionic species selected from Rb.sup.+, Cs.sup.+, Na.sup.+, K.sup.+, or Sr.sup.2+. The intercalable compound is preferably a carbonaceous material, such as graphite.

Some variations provide an alkali metal or alkaline earth metal vapor cell with a solid ionic conductor and intercalable-compound electrodes. The intercalable-compound electrodes are used as efficient sources and/or as sinks for alkali metal or alkaline earth metal atoms, thus enabling electrical control over metal atom content in the vapor cell. Some variations provide a vapor-cell system comprising: a vapor-cell region configured to allow a vapor-cell optical path into a vapor-cell vapor phase; a first electrode; a second electrode electrically isolated from the first electrode, wherein the second electrode contains an intercalable compound intercalated by an element selected from Rb, Cs, Na, K, or Sr; and an ion-conducting layer between the first electrode and the second electrode. The ion-conducting layer is ionically conductive for at least one ionic species selected from Rb.sup.+, Cs.sup.+, Na.sup.+, K.sup.+, or Sr.sup.2+. The intercalable compound is preferably a carbonaceous material, such as graphite.

Hydrometallurgical processes are provided for the recovery of metal values, including cesium, from epithermal mineral deposits, including pharmacosiderite-containing ores. Aspects of the process involve the preferential formation of a cesium alum, and preparation of cesium hydroxide from the cesium alum.

Hydrometallurgical processes are provided for the recovery of metal values, including cesium, from epithermal mineral deposits, including pharmacosiderite-containing ores. Aspects of the process involve the preferential formation of a cesium alum, and preparation of cesium hydroxide from the cesium alum.

The invention discloses a method of solution mining trona by injecting an aqueous solvent into an underground cavity comprising trona to dissolve trona in the aqueous solution and removing the aqueous solution from the cavity at about the WTN triple point (the temperature at which solid phase wegscheiderite, trona, and nahcolite can co-exist in an aqueous solution). Alkaline values from the removed aqueous solution are recovered to produce a barren liquor. The method further includes either (i) treating the barren liquor to produce an aqueous solvent or (ii) treating injected aqueous solvent to reduce clogging at the trona dissolution surface caused by supersaturation of sodium bicarbonate, and precipitation of nahcolite and wegscheiderite as the aqueous solution in the cavity approaches saturation of both dissolved sodium bicarbonate and sodium carbonate.

Provided is a method for filling a stem-side hollow area of an engine valve with metallic sodium. The method includes injecting melted metallic sodium into a cylinder having a larger diameter than an inner diameter of the hollow area of the engine valve, forming a solidified metallic sodium rod having a substantially uniform structure in the cylinder, inserting the metallic sodium into the hollow area of the engine valve through a nozzle having a small diameter, and sealing the engine valve.