Abstract: A nickel-chromium-aluminum alloy includes (in mass %) 12 to 30% chromium, 1.8 to 4.0% aluminum, 0.1 to 7.0% iron, 0.001 to 0.50% silicon, 0.001 to 2.0% manganese, 0.00 to 1.00% titanium, 0.00 to 1.10% niobium, 0.00 to 0.5% copper, 0.00 to 5.00% cobalt, in each case 0.0002 to 0.05% magnesium and/or calcium, 0.001 to 0.12% carbon, 0.001 to 0.050% nitrogen, 0.001 to 0.030% phosphorus, 0.0001 to 0.020% oxygen, max. 0.010% sulfur, max. 2.0% molybdenum, max. 2.0% tungsten, and a remainder of nickel with a minimum content of ?50% and the usual process-related impurities for use in solar power towers, using chloride and/or carbonate salt melts as a heat transfer medium, wherein in order to ensure a good processability, the following condition must be met: Fv?0.9 with Fv=4.88050?0.095546*Fe?0.0178784*Cr?0.992452*AI?1.51498*Ti?0.506893*Nb+0.0426004*AI*Fe, where Fe, Cr, AI, Ti, and Nb are the concentration of the respective elements in mass %.

Abstract: A nickel-chromium-aluminum alloy includes (in mass %) 12 to 30% chromium, 1.8 to 4.0% aluminum, 0.1 to 7.0% iron, 0.001 to 0.50% silicon, 0.001 to 2.0% manganese, 0.00 to 1.00% titanium, 0.00 to 1.10% niobium, 0.00 to 0.5% copper, 0.00 to 5.00% cobalt, in each case 0.0002 to 0.05% magnesium and/or calcium, 0.001 to 0.12% carbon, 0.001 to 0.050% nitrogen, 0.001 to 0.030% phosphorus, 0.0001 to 0.020% oxygen, max. 0.010% sulfur, max. 2.0% molybdenum, max. 2.0% tungsten, and a remainder of nickel with a minimum content of 50% and the usual process-related impurities for use in solar power towers, using chloride and/or carbonate salt melts as a heat transfer medium, wherein in order to ensure a good processability, the following condition must be met: FV 0.9 with FV=4.88050?0.095546*Fe?0.0178784*Cr?0.992452*Al?1.51498*Ti?0.506893*Nb+0.0426004*Al*Fe, where Fe, Cr, Al, Ti, and Nb are the concentration of the respective elements in mass %.

Abstract: A nickel-chromium-iron-aluminum alloy contains (in wt. %)>17 to 33% chromium, 1.8 to <4.0% aluminum, 0.10 to 15.0% iron, 0.001 to 0.50% silicon, 0.001 to 2.0% manganese, 0.00 to 0.60% titanium, 0.0002 to 0.05% each of magnesium and/or calcium, 0.005 to 0.12% carbon, 0.001 to 0.050% nitrogen, 0.0001 to 0.020% oxygen, 0.001 to 0.030% phosphorus, not more than 0.010% sulfur, not more than 2.0% molybdenum, not more than 2.0% tungsten, the remainder nickel with nickel ?50% and the usual process-related impurities, for use in solar power tower plants using nitrate salt melts as the heat transfer medium, wherein the following relations must be satisfied: Fp?39.9 (2a) with Fp=Cr+0.272*Fe+2.36*Al+2.22*Si+2.48*Ti+0.374*Mo+0.538*W?11.8*C (3a), wherein Cr, Fe, Al, Si, Ti, Mo, W and C is the concentration of the respective elements in % by weight.

Abstract: The present invention relates to a process for the separation of vanadium in the form of vanadium oxide, iron-vanadium-oxide, or iron-vanadium from solutions containing both dissolved iron and dissolved vanadium, wherein an aqueous solution containing dissolved iron and vanadium in a molar iron-to-vanadium ratio of above 1:1, preferably above 1:1 and up to 10000:1, more preferably between 5:1 and 1000:1, even more preferably between 5:1 and 100:1, and most preferably between 10:1 and 50:1 and optionally also other elements is oxidized in an oxidation step with a gaseous oxidation media, and wherein the amount of acid in the aqueous solution is kept below the stoichiometric amount of acid required during bivalent iron oxidation and the precipitate thus formed is removed from the solution.

Abstract: The present invention relates to a process for the separation of vanadium in the form of vanadium oxide, iron-vanadium-oxide, or iron-vanadium from solutions containing both dissolved iron and dissolved vanadium, wherein an aqueous solution containing dissolved iron and vanadium in a molar iron-to-vanadium ratio of above 1:1, preferably above 1:1 and up to 10000:1, more preferably between 5:1 and 1000:1, even more preferably between 5:1 and 100:1, and most preferably between 10:1 and 50:1 and optionally also other elements is oxidized in an oxidation step with a gaseous oxidation media, and wherein the amount of acid in the aqueous solution is kept below the stoichiometric amount of acid required during bivalent iron oxidation and the precipitate thus formed is removed from the solution.