Abstract: The method of the present invention is a novel comprehensive process for maximizing the recovery of valuable mineral values from coal ash. Options may also be included for the production of saleable inorganic chemical by-products. The process employs both physical and chemical extraction techniques that maximize the yield of products while reducing the quantity of waste produced. Valuable minerals and chemicals such as cenospheres (hollow microspheres), carbon, magnetite (Fe.sub.3 O.sub.4), alumina (Al.sub.2 O.sub.3), iron oxide (Fe.sub.2 O.sub.3) and iron chloride (FeCl.sub.3) may be produced. Due to removal of carbon, magnetite, and iron oxide from the coal ash, the processed ash comprises a quality pozzolan.

Abstract: Large power transformers such as used at electrical generating plants utilize oil for cooling with the heat removed by air cooled radiators. Several air cooled radiators are removed from the transformers and the oil circulated through plate heat exchangers which provide a heat transfer path to a fluid cooling medium such as water. Flow transducers and electrical temperature sensors may be used to monitor the flow rates of the oil and water, and the temperature of the oil and water in various parts of the system. These parameters are controlled to maximize the transfer of waste heat from the transformer to the water. The heated water is then utilized to perform useful work. For example, in a power plant having package boilers, the boiler makeup water is preheated with the transformer waste heat thereby reducing the energy requirements of the system.

Abstract: A novel method is provided for the production of anhydrous hydrofluoric acid from low-grade metallic fluorides using an intermediate aluminum fluoride compound. The method involves the reaction of low-grade metallic fluorides such as fluorspar with sulfuric acid to produce weak hydrofluoric acid. The weak acid is then reacted with a metallic salt (such as aluminum chloride) to form precipitated aluminum fluoride (AlF.sub.3.3H.sub.2 O). After dewatering, the aluminum fluoride is reacted with strong sulfuric acid to form aluminum sulfate and strong hydrofluoric acid.

Abstract: A method for desulfurization, denitrification, and oxidation, of carbonaceous fuels including a two stage oxidation technique. The carbonaceous fuel, containing ash, along with an oxygen-containing gas is introduced into a first stage partial oxidation unit containing a molten ash slag maintained at a temperature of about 2200.degree.-2600.degree. F. A flux may also be introduced into the first stage partial oxidation unit for the purpose of increasing the basicity and maintaining the viscosity of the molten ash slag at a value no greater than about 10 poise. The carbonaceous fuel is gasified, and sulfur is chemically bound and captured in the molten ash slag. Since the first stage is operated in a gasification mode (reducing atmosphere), essentially all of the nitrogen in the fuel is converted to diatomic nitrogen, which results in low nitrogen oxide emissions upon final combustion.

Abstract: An improved fuel composition is provided comprising in minor proportion a non-dewatered sewage sludge and in major proportion a particulate solid fuel. A method is also provided for the incineration of sewage sludge comprising providing a pumpable admixture of a non-dewatered sewage sludge and a particulate solid fuel and incinerating the admixture.

Abstract: A method for desulfurization and oxidation of carbonaceous fuels including a two stage oxidation technique. The carbonaceous fuel, along with an oxygen-containing gas is introduced into a first stage partial oxidation unit containing molten slag maintained at a temperature of about 2200.degree.-2600.degree. F. A flux may also be introduced into the first stage partial oxidation unit for the purpose of maintaining the viscosity of the molten slag at a value no greater than about 10 poise. The carbonaceous fuel is gasified, and sulfur is chemically bound and captured in the molten slag. The combustible gas derived from partial oxidation and gasification is directed along a substantially horizontal path to a second stage oxidation unit for final combustion. The sulfur-containing slag is removed to a water-sealed quench system for disposal.