Abstract: In so-called rising main sewers in which sewage can be subjected to conditions when the supply of oxygen is deficient noxious sulphides can be produced which are a nuisance. The present invention provides a composition for the treatment of sewage so that the production of noxious sulphides is minimized under these conditions.The composition of the invention comprises an aqueous solution of ferric sulphate and ferric nitrate in amounts such that the molecular ratio of ferric sulphate to ferric nitrate is from 1:0.5 to 1:3. Optionally the composition may contain nitric acid in an amount of up to 2.5 molecules per molecule of ferric sulphate.These compositions are produced by reacting in aqueous solution nitric acid with ferrous sulphate in the absence of separately added sulphuric acid in such amounts that nitric acid is sufficient to produce the desired molecular ratio of ferric sulphate to ferric nitrate and the reaction is conducted at a temperature of at least 60.degree. C. and not greater than 100.degree.

Abstract: A process for the preparation of rigid beads, of cross-linked polyester resin which beads may be solid or vesiculated, by forming an oil-in-water or a water-in-oil-in-water emulsion in which the oil phase contains an unsaturated polyester resin and an unsaturated organic monomer to provide said cross-linking and thereafter heating the emulsion to a temperature of at least 45.degree. C. before initiating polymerization of the oil phase by the introduction into the system of a polymerization initiator, and promoter system, if the latter is not already present in the emulsion.

Abstract: A method for the production of a monolayer catalyst by treating the catalyst substrate having bound water residues on its surface and substantially free of physisorbed water with an organic solution of a catalyst precursor, reacting the precursor with the bound water residues, removing excess precursor and solvent and decomposing the precursor to a catalytically effective compound. The catalyst substrate preferably is titanium dioxide and the precursor preferably is vanadium oxychloride.

Abstract: Aqueous pastes have been prepared by dispersing dried particulate material in water in the presence of a dispersing agent.A new process for the manufacture of aqueous pastes involves two-stage filtration in which a first stage filter cake is mixed with a dispersing agent in an amount sufficient to render the cake free-flowing which is then subjected to a second stage pressure filtration and the cake is then homogenized.Preferably the cake is of titanium dioxide and the cake from the first filtration is mixed with the dispersing agent in a sand mill. A membrane pressure filter is preferably used in the first and second filtration stages. During homogenization preferably a further amount of the dispersing agent is mixed with the filter cake. Aqueous paste prepared by this new process can have solids contents in excess of 70% by weight.

Abstract: A method of measuring mean particle size and/or standard deviation of particles involves illuminating a suspension of the particles with three beams of radiation of wavelengths R.sub.1, R.sub.2 and R.sub.3 and measuring the beam intensities passing through the suspension. The results are compared with those of the liquid medium free of particles and attenuation ratios of the beams at wavelengths R.sub.1 and R.sub.3 and at R.sub.2 and R.sub.3 are compared with previously calculated values for these ratios.This comparison enables the desired parameters to be obtained easily; preferably by using a spectrophotometer in which two or more optical densities at two or more wavelengths are compared simultaneously.The method is of particular use for aqueous suspensions of titanium dioxide pigment using wavelengths R.sub.1, R.sub.2 and R.sub.3 of 480 to 520 nanometers, R.sub.2 of 600 to 800 nanometers and R.sub.3 of 400 to 480 nanometers and not greater than (R.sub.1 -40) nanometers.

Abstract: Commercial titanium dioxide pigments to be used in paper laminates have been prepared by a method which involves calcining a coated pigment. A new pigment having an excellent stability to degradation by light when used in such laminates is produced without calcination of the coated pigment.The pigment comprises rutile titanium dioxide particles having an inner coating containing cerium and phosphate radicals and an outer coating containing aluminium and phosphate radicals and optionally hydrous alumina.The pigment preferably contains a surface stabilizer such as a fluoride, preferably calcium fluoride. Amounts of cerium phosphate are from 0.05% to 1% (as CeO.sub.2) and of aluminium phosphate between 0.05% and 5% by weight (as Al.sub.2 O.sub.3) on TiO.sub.2.

Abstract: A method for the manufacture of a total oxidation catalyst in which titanium dioxide is treated with vanadium pentoxide and then washed until the wash liquid is substantially free of vanadium pentoxide. This method produces a catalyst which will totally oxidize an oxidizable organic compound to carbon dioxide.

Abstract: A method for the manufacture of a selective oxidation catalyst by heating titanium dioxide in the presence of water prior to treating the titanium dioxide with vanadium oxytrichloride in vapor form and then heating the treated titanium dioxide. This treatment with water and vanadium oxytrichloride is repeated a number of times until the desired selective oxidation catalyst is obtained.

Abstract: A container consisting of a flexible body, base and cover and having flexible discharge and filling tubes in the base and cover, respectively, and flaps attached to the exterior of the base; the discharge and filling tubes and flaps having releasable securing means. The container may be provided with means to control the rate of discharge of the contents of the container from the discharge tube.

Abstract: A process for the treatment of aqueous sulphuric acid solutions containing dissolved ferrous sulphate comprising forming such a solution containing from 140 to 220 grams/liter free sulphuric acid in a first zone; adjusting the pH value of the solution in this zone to one in the range 3 to 4 by the addition of finely-divided calcium carbonate thereby precipitating calcium sulphate; passing the slurry thus produced to a second zone; adding to the second zone an aqueous solution of sulphuric acid containing from 3 to 80 grams/liter of free sulphuric acid; adjusting the pH value of the mixture in the second zone to one in the range 3.5 to 6 by the addition of finely-divided calcium carbonate thereby precipitating calcium sulphate and thereafter recovering from the second zone calcium sulphate suitable for use in the manufacture of plasterboard.

Abstract: Apparatus and process for reducing the rate of erosion of electrodes between which an arc is sustained by the provision of a field coil around the electrode which is supplied with direct current and the oscillation of that direct current supply at a frequency in the range 5.times.10.sup.-1 to 1.times.10.sup.-4 Hz.

Abstract: An improved multiphase series reactor consisting of a number of interconnected coils, each coil being formed from sub-coil wherein the sub-coils consist of a number of laterally-spaced single-plane spirals, each spiral being formed from hollow electrical-conducting material. Each sub-coil is wound in such a manner that electrical power supplied to the coils passes through the constituent spirals of the sub-coils in the same direction. Coolant introduced into the interior of the hollow-electrical conducting material passes through the spirals of the sub-coils before being withdrawn.

Abstract: Process for the recovery of chlorine from chlorine-containing gas mixtures in a multi-stream heat exchanger wherein the chlorine-containing mixtures are separated from other gases which would solidify or liquify in the process, either before or after compression of the mixture, and is then cooled below the dew-point of chlorine in one stream of the heat exchanger; the liquid and gaseous phases thus produced are then separated and re-passed separately through the heat exchanger, the chlorine passing to recovery and the gas phase to re-cooling before being re-passed once more through the heat exchanger prior to discharge and wherein a predetermined mixture of gaseous and liquid phases is also recycled separately through the heat exchanger before re-compression and return via the heat exchanger to the phase-separation apparatus.

Abstract: A titanium chelate being the reaction product of ethylene glycol titanate, propylene glycol titanate, diethylene glycol titanate or hexylene glycol titanate and lactic acid, alpha-hydroxy-butyric acid, citric acid or glyceric acid. The chelates are particularly useful for gelling hydroxyl polymers such as polyvinyl alcohol in the form of solutions.

Abstract: Pelletizing damp gypsum to render the gypsum easily calcinable by a process in which the damp gypsum is agitated, and when moisture is observed at the surface of the forming pellets a dry powdered compound of calcium is added until the forming pellets are coated with the powdered compound to become free-flowing.

Abstract: A pressure vessel base closure means including a pair of flat disc-like members spaced apart by a peripheral outer cylindrical member and an inner perforated cylindrical member, and there being provided between the two flat disc-like members a plurality of radially directed ribs to provide rigidity to the base closure means. The base closure means is particularly useful for a reactor in which a bed of fluidized solid is maintained by the passage of a gas into the reactor through the base via the chamber between the two flat disc-like members.

Abstract: A supported vessel having a number of outwardly directed projections on the side of the vessel which are fixed to the outer end of horizontally disposed webs, the inner end of the webs being supported on a supporting structure, the lower end of which is secured in the ground, the weight of the vessel being transmitted to the webs through the support structure. The invention also claims a support for such a supported vessel.

Abstract: Apparatus for use in the production of a colored photographic reproduction of a black and white negative which consists essentially of a light-free enclosure, a baffle having an aperture and extending across the housing with means to mount the black and white negative over the aperture, means to carry one or more colored filters and means to generate a pulse of light to illuminate the negative in order that a copy may be taken by a camera suitably mounted.

Abstract: Process and apparatus for the production of finely-divided metal oxides by the oxidation of the corresponding metal halide wherein a secondary gas is introduced into a heated primary gas through apertures in the reaction zone wall, the apertures formed with at least two different cross-sectional areas along their length, the small cross-sectional area being at the inlet end of the aperture for the secondary gas.

Abstract: A transducer having a primary coil and at least one secondary coil wound on a hollow support with a number of electrically conducted links axially spaced along the secondary coil with the links connecting spaced turns of the secondary coil so that the transducer when in use has an output of desired form. The transducer is particularly useful for producing an output voltage from which the position of the core and anything connected to it can be deduced.