Abstract: A granular fertilizer with a coating which is decomposable by soil microorganisms, preferably a coating which is decomposed and degraded both on the surface layer of the soil and in the soil, and a process for producing the granular fertilizer, which coating contains a poly 3-hydroxy-3-alkylpropionic acid as an indispensable ingredient, and if necessary, a resin or a low-molecular resin and further, if necessary, an inorganic or organic powder, and which process comprises adding an organic solvent solution of the poly 3-hydroxy-3-alkylpropionic acid, and if necessary, the resin, and if necessary the powder (dispersed in the solution) to a granular fertilizer in fluided state in the form of spray, and when added, blowing a high speed hot air stream onto the fertilizer to thereby instantaneously remove the solvent and also dry the resulting fertilizer.

Abstract: A coated or encapsulated granular fertilizer which comprises an olefin polymer and/or copolymer and a polyether polyol in a defined amount. The olefin polymer is an ethylene or propylene homopolymer and/or a copolymer of an olefin monomer and a copolymerizable monomer such as olefinic monomers, vinyl acetate and carbon monoxide. The polyether polyol is polymers of ethylene oxide, propylene oxide and mixtures thereof with or without etherification with polyhydric alcohols. By the addition of the polyether polyol, a dissolution rate of the fertilizer can be arbitrarily controlled without a sacrifice of physical properties of the coated film.

Abstract: A fertilizer with a degradative coating wherein the dissolving-out rate of the fertilizer component can be controlled by adjusting the composition of the coating component and the residual capsule after the dissolving out degrades by light is provided, which degradative coating comprises as its active ingredient, at least one member of polyolefin resins and at least one member selected from the group consisting of rubbery resins and ethylene-vinyl acetate-carbon monoxide copolymer.

Abstract: A granular fertilizer with a degradative coating characterized in that after it has been applied to soil and its fertilizer component has dissolved out, the resulting coating part degrades rapidly is provided, which degradative coating comprises an ethylene-carbon monoxide copolymer as its indispensable component and a rubbery resin, an ethylene-vinyl acetate copolymer resin or powder as an optional component.

Abstract: A small amount of chlorine contained in the converted potassium sulfate obtained by dry-mixing and heating potassium chloride with sulfuric acid or potassium hydrogensulfate can greatly be reduced by totally pulverizing the potassium sulfate to 60 mesh pass, and then calcining at 300.degree. to 500.degree. C. for 5 minutes to one hour. The chlorine content is further reduced by adding a small amount of water or dilute sulfuric acid prior to calcination.

Abstract: A process for producing a purified hydrochloric acid from hydrogen chloride gas generated by reacting an alkali chloride with sulfuric acid is provided, which process comprises washing the hydrogen chloride gas with a hydrochloric acid having a saturation concentration and having the resulting gas absorbed in water.This process does not require such a particular purification step as redistillation or reabsorption.

Abstract: Hydrochloric acid produced by reacting an alkali chloride with sulfuric acid to prepare hydrogen chloride gas, followed by having the gas absorbed in water, contains a slightest amount of Br.sub.2 and other coloring materials as volatile impurities, but such amounts of impurities can be removed according to a purifying process in which the resulting hydrochloric acid is treated with an inert gas or a mixture of an inert gas with oxygen.