Abstract: The present invention relates to a wet process for the manufacture of phosphoric acid, which process essentially comprises a digestion step in which phosphate rock is digested by means of phosphoric acid and sulfuric acid to form a slurry containing highly concentrated phosphoric acid together with calcium sulfate hemihydrate, and a separation step in which the slurry is filtered for separation of calcium sulfate hemihydrate from the highly concentrated phosphoric acid (in which the concentration of P205 in the product acid is higher than 40% by weight, based on the weight of the product acid) and which is characterized by supplying active silica at a ratio of 0.2-5% by weight, based on the weight of phosphate rock, in order that active silica may be present in the above mentioned digestion step.

Abstract: The present invention relates to a working method of breaking up a ship, particularly a large ship, and is characterized by cutting the hull to shorten the length thereof as it is floating on the sea, and more particularly characterized by, on the cutting of the hull, inserting a buoyancy body under the stem portion or the stern portion to trim the hull and floating up said portion and locating there a marine workshop, drawing the hull into the marine workshop while performing breaking up the hull. According to the present invention, it is possible to break up a hull without special harbor facilities and even at locations such as the lee of island and other position where there is no harbor facilities. Also, since the hull is drawn in the marine workshop and broken up to shorten the length of the hull, the working is greatly simplified compared with a prior method wherein the hull is broken up to shorten the height thereof, and as a result the working period can be shortened.

Abstract: The present invention is characterized by cutting and breaking up a hull of large ship in the floating situation on the sea so as to shorten the length of the hull, transporting the broken up objects to a product making workshop, and subdividing said objects further thereby breaking up into products. Said product making workshop is constructed so as to supply power etc. required for the breaking up process.A breaking up method according to the present invention does not require harbor facilities such as crane etc. so that it does not have any limitation with respect to the breaking up place and since it allows the product making operation from the broken up objects to be performed on the sea, the breaking-up process can be simplified.