Abstract: The present invention is a process for the rapid conversion of iron oxide-containing material into iron carbide. The process includes a first step in which the iron oxide-containing material is contacted with a reducing gas that contains a high concentration of hydrogen gas to form a metallic iron-containing intermediate product and a second step in which the metallic iron-containing product is contacted with a carburizing gas having high concentrations of hydrogen and carbon monoxide gas to produce iron carbide. The unused carbon monoxide in the off-gas from the second step is not recycled to the second step but is used as a fuel source.

Abstract: A method for the production of fine-grain tungsten carbide (WC) powder comprising heating a tungsten precursor compound in contact with a gas mixture including a hydrocarbon such as methane (CH4). The method is preferably a one-step continuous method wherein the heating rate and reaction temperature is well controlled for the economical production of high quality tungsten carbide powder. The tungsten carbide powder advantageously has a high purity and a small crystallite size and can be used in the manufacture of products such as cutting tools having high wear resistance.

Abstract: A method for treating a brass fixture having a fluid-contacting surface with lead dispersoids exposed thereon to reduce lead leaching into a fluid supply by contacting the brass fixture with a liquid metal solution selected from the group consisting of a liquid sodium solution, a liquid potassium solution and a liquid metal alloy solution to dissolve lead dispersoids from the fixture, wherein the metal alloy comprises a metal selected from the group consisting of sodium and potassium.

Abstract: A process for controlling the conversion of reactor feed to iron carbide is disclosed. The reactor feed is subjected to a process gas in a fluidized bed reactor (10), and the off-gas from this reaction is analyzed (56) to determine its composition and the temperature (64) and pressure (66). A stability phase diagram is generated based on the temperature. Different regions of the stability phase diagram are representative of different products being formed by the conversion of the reactor feed. Based on relative concentrations of the individual gases in the off-gas and the total pressure, a point is plotted on the stability phase diagram indicative of the favored reaction product. The process parameters can then be adjusted to insure that iron carbide can be produced from the reactor feed based on the stability phase diagram. In one embodiment, the rate of conversion of the reactor feed into iron carbide is controlled.

Abstract: A process for using iron metal or an iron-containing sulfide reagent as a co-additive to extend the usefulness of sodium in refining crude lead bullion.

Abstract: A process for using an iron-containing sulfide reagent and a previously formed copper speiss as joint co-additives to extend the usefulness of the sodium in refining crude bullion which has less than about 1.3 wt. % sulfur.

Abstract: Previously formed copper speiss in an amount of about 6.5% by weight is a co-additive which extends the usefulness of sodium in refining crude lead bullion, which has a sulfur content generally less than about 1.3% by weight.

Abstract: A novel process for the conversion of reactor feed to iron carbide is provided. The process includes the step of preheating the reactor feed in an oxidizing atmosphere. The iron carbide produced by the process is particularly useful in the production of steel.

Abstract: A novel design for a fluidized bed reactor is provided. The fluidized bed reactor includes a baffle system to ensure the proper residence time of the feed materials. The fluidized bed reactor also provides a novel method for reducing the negative effects of thermal expansion in the reactor.

Abstract: Fume generated by roasting speiss is contacted with an oxygen-containing gas at an elevated temperature for a sufficient time to product arsenic and antimony products which may be separated from each other by means such as condensation. Further, in the roasting of antimony-containing phases (such as speiss) the presence of arsenic can enhance the volatility of the antimony.

Abstract: Indium-containing feedstocks, such as flue dusts from a refining or smelting process, are treated to increase the concentration of indium and at the same time to reduce the concentrations of lead, copper, and arsenic. The flue dusts are treated in a sodium-doped lead bath at temperatures of 675.degree. to 800.degree. C. Soda ash in the amount of 15 to 35 weight percent is blended with the feed stock and added to the sodium-doped lead bullion. The sodium reacts with the dusts to form a liquid dross, which is removed, cooled, and crushed. The powdered dross is water leached to remove the sodium salts. The indium remains in the filler cake and can be processed by conventional methods for the recovery of indium. About 95% of the indium reports to the filter cake, while lead retention in the filter cake is only about 5-15% of the initial lead content in the dust. A majority of the zinc also reports to the filter cake.

Abstract: A method of controlling product quality in a conversion of reactor feed to an iron carbide-containing product in a fluidized bed reactor. A Mossbauer analysis is performed on product samples leaving the fluidized bed reactor, and a regression analysis is performed on the Mossbauer data. Depending upon the results of the regression analysis, process parameters are adjusted in order to obtain a product having a desired composition. Adjustments are made to the temperature and pressure in the fluidized bed reactor, rate of feed to the fluidized bed reactor, and the composition of the process gas which reacts with the reactor feed in the fluidized bed reactor, dependent upon the analysis results.

Abstract: Fume generated by roasting speiss is contacted with an oxygen-containing gas at an elevated temperature for a sufficient time to produce arsenic and antimony products which may be separated from each other by means such as condensation. Further, in the roasting of antimony-containing phases (such as speiss) the presence of arsenic can enhance the volatility of the antimony.

Abstract: A novel process for the recovery of alumina and potassium sulfate from alunite is provided comprising leaching the alunite with potassium hydroxide to which no sodium materials have been added, said leach solution being saturated with potassium sulfate. Aluminum values are solubilized into the leachate, and potassium and sulfur values are rendered soluble, but remain in the residue. The leachate is desilicated if necessary, preferably with lime, and aluminum trihydroxide is precipitated therefrom, followed by calcining to alumina product. The residue is leached to solubilize potassium sulfate in a secondary leach and the potassium sulfate product crystallized therefrom. Potassium hydroxide is regenerated from a portion of the potassium sulfate secondary leachate by several methods.Novel procedures for regenerating alkali metal hydroxides from the corresponding sulfates are also provided including routes involving formates and carbonates as intermediates and pyrohydrolysis.