Abstract: The invention relates to a process for granulating ammonium nitrate fertilizer with a nitrogen content of between 25% and 34% by weight, by forming a mix of NH.sub.4 NO.sub.3, limestone and/or dolomite, ammonium sulphate and/or ammonium phosphates and MgSO.sub.4, this latter being added in any one of its crystalline forms and its various degrees of hydration, then granulating or prilling, and cooling.

Abstract: A valve arrangement of an irrigation system includes a by-pass; for controlling the return flow of a pilot valve, which by being connected between the outlet connection from the pilot valve and the return connection to the pilot valve eliminates the need for a return circuit and enables the arrangement to be connected downstream to an open circuit network used for the pulsating delivery of an irrigation liquid.

Abstract: A continuous process is described for the preparation of fertilizers from animal waste consisting of the following steps:a) anaerobic fermentation of waste up to BOD.sub.5 of 300-2000,b) treatment with HNO.sub.3 up to pH 1-2,c) treatment with Ca(OH) up to pH 6.5-7 and S.A.R. index<6, with the addition of small quantities of H.sub.2 O.sub.2 before or after step c).

Abstract: A device for the automatic pulsating delivery of an irrigation liquid is described, connectable upstream to the liquid source of constant or substantially constant pressure and downstream to an open-circuit distribution network provided with pressure-sensitive secondary valves which in response to pressure change open or close to enable the irrigation liquid to emerge. An irrigation system is also described in which said device is connected to a distribution network comprising a plurality of valves sensitive to pressure change and each provided with a delivery nozzle.

Abstract: Process for the removal of cadmium from solutions of phosphoric acid derived by the sulphuric and nitric digestion of phosphatic rocks, including the following steps:adding to the phosphoric acid solution bromide ions, such as hydrogen bromide or the bromides of alkaline metals, in quantities ranging from 100 to 3500 ppm;adding to the same solution of at least one condensed polyphosphatic compound in a concentration of 1 to 5% by weight;eluting the mixture thus obtained through at least two beds of an ion-exchange resin with a styrene divinylbenzene matrix at a temperature ranging from 15.degree. to 50.degree. C.

Abstract: A disposable sprinkler line for localized irrigation comprising a hose having outlet holes at equal distances from each other, and inner flexible membranes attached to the inner wall of the hose capable of forming interstices with the inner wall in the presence of a water flow. The inner flexible membranes are provided with openings at regular intervals and staggered relative to the outlet holes in the hose for receiving the pressurized water.

Abstract: A continuous process is disclosed for the production, with a high yield, of high purity silicon tetrafluoride, starting from an aqueous solution of fluorosilicic acid, which comprises:(a) reacting an aqueous solution of fluorosilicic acid with concentrated sulphuric acid, carried out with a short residence time and preferably under fluido-dynamic conditions of turbulence, inside a reaction zone;(b) separating a gaseous stream containing silicon tetrafluoride from a liquid stream of aqueous sulphuric acid, carried out inside a separation zone, directly connected with the reaction zone;(c) washing said gaseous stream with concentrated and cold sulphuric acid carried out inside a washing zone, for the purpose of separating a gaseous stream of purified silicon tetrafluoride; and, possibly(d) further purifying said gaseous stream of purified silicon tetrafluoride by means of techniques of adsorption on an adsorbent solid material.

Abstract: A device for the automatic and pulsed delivery of an irrigation liquid, which can be connected, at its upstream side, to a source liquid under a constant or substantially constant pressure, and at its downstream side, to a distribution network equipped with pressure-responding valves. These valves are capable of closing, during the step charging of the distribution system, at a pressure equal to, or substantially equal to, the liquid feed pressure, and of opening, during irrigation liquid expelling, when the pressure decreases under said value. The device comprises a Venturi device, fed with the same irrigation liquid, from whose region of constricted stream a duct is branched off, to transmit to a sliding member depressure generated by the Venturi.

Abstract: Calcium-urea nitrate [Ca(NO.sub.3).sub.2.4CO(NH.sub.2).sub.2 ] is produced by means of a process, according to which:a liquid composition is prepared, at a temperature not higher than 170.degree. C., which contains urea and calcium nitrate, in a molar ratio to each other equal to, or approximately equal to, 4/1, and having a water content comprised within the range of from 0 to 15% by weight;said liquid composition is sprayed, through a spray nozzle, on previously formed solid particles of calcium-urea nitrate, kept moving at a temperature comprised within the range of from 40.degree. to approximately 100.degree. C., and under a stream of an inert gas;calcium-urea nitrate is recovered from said solid products from the spray.The so obtained calcium-urea nitrate is in the form of a granular and free-flowing solid, free from the tendency to form dusts, and is useful in agriculture as a nitrogenous fertilizer.

Abstract: A process is disclosed for the preparation of potassium nitrate by means of the reaction of nitric acid with potassium carbonate, wherein potassium carbonate is obtained by means of an electrochemical process.