Abstract: The iron content of the TiO.sub.2 -containing precursor is subjected to a direct reduction to effect a metallization of at least 90%. The reduced product is separated into magnetic and nonmagnetic fractions by magnetic separation. To oxidize the metallic iron, the magnetic fraction is subjected to an oxidation in an acid medium with agitation at a pH value below 2, under a pressure of 12 to 24 bars, and at a temperature from 150.degree. to 210.degree. C. with a supply of an oxygen-containing gas that contains at least 90% oxygen. When the suspension has been pressure-relieved, the hematite which has been formed is separated from the TiO.sub.2 concentrate.

Abstract: A multilayer membrane is composed of a carrier layer, a porous supporting layer and a separating layer. The carrier layer consists of fibers of polyamide, polyvinylidene difluoride, polyester or glass; the porous supporting layer consists of a polysulfone, polyvinylidene difluoride, polyethersulfone, polyimide, polyvinyl alcohol, polyurethane, polyacrylonitrile or polyether imide; the separating layer consists of polyvinyl alcohol. The separating layer is nonporous and has a structure having a high microcrystalline content. A process of manufacturing that membrane is also described.

Abstract: Disclosed are a process and apparatus for separating liquid ash from an exhaust gas which is formed by the combustion of carbonaceous fuels. The exhaust gas is at a temperature of from 1200.degree. to 1800.degree. C. and under a pressure from 1 to 100 bars and has an ash content, consisting of liquid particles, of 0.1 to 60 g/sm.sup.3. In the process, the ash-containing exhaust gas leaving the combustion chamber is directed to a housing in which there is at least one baffle surface oriented substantially transversely to the direction of flow of the exhaust gas which may be preceded by a centrifugal separator and/or succeeded by a ceramic filter element.

Abstract: Shaped bodies which are improved in high-temperature strength, resistance to thermal shock and fatigue limit can be made of a lightweight cast material which consists mainly of aluminum and in addition contains 5 to 15% by weight magnesium silicide.

Abstract: In an electrolyzer having bipolar cells, which are arranged in a row and consist each of two metallic partitions, spring-elastic electrodes bearing on the partitions, and a diaphragm which is disposed between the electrodes and is spaced from the electrodes by spacers, contact between the spring-elastic electrodes and the diaphragm is prevented by disposing the spacers of each cell directly opposite to each other and aligned with the spacers of the other cells.

Abstract: A process for preparing a conductive, acicular zinc oxide, comprising the steps of: preparing a zinc oxide slurry comprising an acicular zinc oxide, a salt of at least one metal selected from the group consisting of aluminum, gallium, indium and tin and an aqueous solution of an alkali metal hydroxide and having a pH value maintained at 10 to 13, adjusting the pH value of said zinc oxide slurry to 5 to 9 while stirring, aging the slurry, separating the zinc oxide present in the slurry by filtration, washing and drying the separated zinc oxide, and then firing the dried zinc oxide at 500.degree. to 700.degree. C. in a reducing atmosphere.

Abstract: The aqueous alkali chloride solution is coarsely purified first. In the succeeding fine purifier the solution, which contains calcium ions, magnesium ions and undissolved magnesium compounds, is passed through a plurality of purification stages (ion exchange stages), which contain cation exchange granulate. In the fine purifier the solution having a pH value of about 10 to 11 is passed through a first ion exchange stage and the solution coming from the first ion exchange is acidified to decrease its pH value by at least 0.5. The solution is subsequently passed through at least one second ion exchange stage and a solution which is virtually free of undissolved magnesium compounds is withdrawn from the fine purification means. The acidified solution fed to the second ion exchange stage has preferably a pH value of 5 to 10.

Abstract: A method of determining the weight per unit of area of conversion layers, particularly of phosphate layers, on metals, in which the heat radiated from the dry surface which is covered with the conversion layer and is at the temperature T and the heat radiated from a reference surface or a reference cavity which is at the temperature T+t are periodically measured at a temperature between 15.degree. and 50.degree. C. by a wavelength-insensitive electic infrared detector. t is preferably selected in the range from +15.degree. to +3.degree. C. from -15.degree. to -3.degree. C. above or below T. The weight of the conversion layer per unit of area is determined from the amplitude of the resulting electric alternating signal. The radiant heat is suitable measured by an infrared detector having a sensor which consists of a pyroelectric sheet of polyvinylidene fluoride.

Abstract: The process of making a multilayer membrane composed of a carrier layer, a porous supporting layer and a separating layer includes making a modified polyvinyl alcohol by decomposing a polyvinyl ester or ether until the proportion of the vinyl alcohol monomer units in the modified polyvinyl alcohol corresponds to that in a material consisting of 80 to 95% of the polyvinyl ester or ether and 20 to 5% of a polyvinyl alcohol obtained by completely decomposing the polyvinyl ester or ether; preparing a composite material consisting of the carrier layer and the porous supporting layer, preparing a dilute aqueous solution containing 1 to 10% by weight of the modified polyvinyl alcohol; preferably storing the dilute solution at temperatures from -10.degree. to +10.degree. C., preferably from 0.degree. to 5.degree. C.

Abstract: A channel plate assembly comprises parallel plates, which are joined to each other and define passages for a first flowing fluid. Each of said passages is continuously defined on all sides in the direction of flow. Parallel plates are interconnected by spacers, which are spaced apart in the direction of flow and have a width that is smaller than the width of each passage which is continuously defined in the direction of flow. A process of manufacturing the channel plate assembly, two fixtures for use in carrying out the process and the use of the channel plate assembly for supplying and/or discharging a first flowing fluid in a plate apparatus are provided.

Abstract: A zinc- and lead-containing residue from a metallurgical plant is reprocessed by a thermal treatment in a circulating fluidized bed system. A major part of the heat demand is satisfied by a combustion of solid carbonaceous material in the fluidized bed reactor of the circulating fluidized bed system. A reducing fluidizing gas, which is virtually free of free oxygen, is fed to the lower part of the fluidized bed reactor. A solid carbon content of from 5 to 30% is adjusted in the fluidized bed in the lower portion of the fluidized bed reactor, which is supplied in its upper portion with oxygen-containing gases and in which CO.sub.2 is formed only at such a rate that zinc metal is not reoxidized. Substantially all solids are removed in a recycling cyclone from the suspension discharged from the reactor and the removed solids are recycled. The gas is cooled to a temperature at which zinc metal is oxidized to ZnO. The dust-like zinc compounds and lead compounds are removed from the gas.

Abstract: Granular coal is combusted in a circulating fluidized bed system comprising a combustion chamber, a separator and a recycle line for recycling solids from the separator to the combustion chamber. Gas from carbonization is added to the oxygen-containing combustion gas withdrawn from the combustion chamber and is at least partly combusted in said combustion gas to increase the temperature of the combustion gas to about 850.degree. to 1200.degree. C. The gas from carbonization is produced by the heating of granular coal.

Abstract: The process for cleaning collecting surfaces of dedusting electrostatic precipitators includes the steps of introducing a coarse-grained cleaning dust into the dedusting electrostatic precipitator, collecting at least the cleaning dust electrostatically in the dedusting electrostatic precipitator and periodically removing the cleaning dust so collected from the collecting surfaces to form a collected dust. To provide a more complete cleaning, the cleaning dust is fed into a gas-flowless space above the fields containing the collecting electrodes and the cleaning dust is distributed in the gas-flowless space according to the cleaning requirements. An apparatus for performing the above cleaning process is also described.

Abstract: The activating agent which is based on titanium(IV) phosphate and intended for use in the activation of metal surfaces before a zinc phosphating treatment contains one or more copper compounds and has a Ti:Cu weight ratio of 1:100 to 60:1 and optionally contains in addition at least one of the components consisting of condensed phosphate, silicate, complexing agent, water-soluble organic polymer, thickening agent, and surfactant. It is used to prepare aqueous activating baths for activating iron, steel, galvanized steel, zinc alloy-plated steel, aluminum-plated steel and aluminum before a zinc phosphating treatment, which baths contain 0.001 to 0.060 g/l Ti, 0.020 to 1.2 g/l orthophosphate (calculated as P.sub.2 O.sub.5), and 0.001 to 0.1 g/l Cu and so much alkali that the bath has a pH value of 7 to 11, preferably of 7.5 to 10.

Abstract: A process and apparatus are used for purifying dust- and pollutant-containing exhaust gases, which are first subjected in a first stage to a dry purification in a mass separator and are subsequently subjected in a second stage to an electrostatic purification in an electrostatic precipitator. In the second stage the exhaust gases are passed through one or more fields provided with liquid-wetted collecting electrodes, which define gas passages. The electrostatic precipitator also has an overflow trough and a collecting trough for each collecting electrode. Liquid supplied to the overflow trough flows onto the collecting electrode and then is collected in the collecting trough.

Abstract: Disclosed is a process for phosphating a galvanized surface, particularly of galvanized steel wherein the surface is contacted for up to 10 seconds with a phosphating solution which contains accelerator, particularly nitrate,0.5 to 5.0 g/l zinc,3 to 20 g/l phosphate (calculated as P.sub.2 O.sub.5),0.3 to 3 g/l magnesiumat a weight ratio of magnesium: zinc=(0.5 to 10):1 and has an S value in the range from 0.2 to 0.4 preferably in the range from 0.2 to 0.3, and is replenished with a concentrate in which the weight ratio of zinc to phosphate (calculated as P.sub.2 O.sub.5) is in the range from (0 to 1):8.It is particularly desirable to use a phosphating solution which contains up to 1.5 g/l zinc, preferably 0.5 to 1 g/l zinc, at a weight ratio of magnesium: zinc of (0.5 to 3:1, nickel ions in an amount of up to 1.5 g/l, preferably in an amount of up to 0.5 g/l and simple or complex fluoride in an amount of up to 3 g/l, preferable 0.1 to 1.5 g/l (calculated as F in each case).

Abstract: A process is disclosed for the preparation of tertiary alcohols, alpha-alkyl substituted nitriles, alkyl-substituted imines or tertiary amines by alkylation of a starting material that is a carbonyl compound or a nitrile followed by hydrolysis wherein the alkylation is carried out with the aid of a reaction system formed by suspending a mixture of:substantially 15 to 25% by weight of methyllithium or ethyllithium;substantially 35 to 45% by weight of an inorganic compound selected from the group which consists of at least one metal oxide selected from the group which consists of SiO.sub.2, Al.sub.2 O.sub.3, and CaO, and synthetic anhydrous aluminum silicate; andsubstantially 35 to 45% by weight of a paraffin oil or wax; in an organic solvent selected from the group which consists of:C.sub.5 to C.sub.10 saturated aliphatic hydrocarbons, C.sub.5 to C.sub.

Abstract: The apparatus comprises a container which has a central cooling chamber and an annular chamber which surrounds the cooling chamber and contains catalyst. The gas mixture to be reacted contains H.sub.2 S and SO.sub.2 enters the annular chamber and first flows through the catalyst. The cooling chamber contains at least one coolant line and is provided with a passage for gas mixture coming from the annular chamber and with a gas outlet. The cooling chamber is provided at its bottom end with a drain for the liquid elementary sulfur .

Abstract: Fine-grained fuels are gasified in a fluidized state with a mixture of gasifying agents which comprise oxygen, water vapor and/or carbon dioxide. NH.sub.3 is substantially entirely removed from the product gas from the gasifier. All or part of the NH.sub.3 is combusted and any remaining NH.sub.3 is added to the exhaust gas from the combustor. In a preferred embodiment the content of nitrogen oxides and/or NH.sub.3 in the exhaust gas from the combustor and NH.sub.3 is supplied to the combustor at such a controlled rate that the contents of nitrogen oxides and NH.sub.3 in the exhaust gas to which NH.sub.3 has been admixed are minimized.

Abstract: In a fusion-metallurgical process of producing fine-grained hereogeneous, ductile alloys which contain Mg.sub.2 Si, the grain size of the Mg.sub.2 Si crystallites formed by primary solidification is kept below 30 .mu.m by doping the molten alloy with 0.05 to 2% by weight of phosphorus.