Cominco, Ltd.

John T Higgins

Gordon C Hildred

Stewart G Bexton

James G Whitham

In the processes for the production of solid particulate sulfur by prilling or granulation, wherein molten sulfur emanates from a spray means, such as a prilling device or spray nozzle, interruptions occur in the flow of sulfur from the spray means. The uneven flow of molten sulfur from a spray means can be substantially eliminated by applying vibration to the spray means, preferably in the diection of flow of molten sulfur through the spray means, at a low frequency in the range of 0.2 to 30 cycles per second. The molten sulfur emanating from the spray means is at a temperature of at least one Celsius degree above the melting temperature of sulfur and under a pressure of at least 250 Pa. The flow rate of sulfur from the spray means is uniform and steady, the particulate sulfur product is hard and closely sized, and the emission of sulfur fines discharging from the process is reduced.

Sulfur prilling

A process is disclosed for the production of a urea sulfur fertilizer by mixing urea and molten sulfur to obtain a molten mixture and solidifying the molten mixture to obtain a homogeneous, solid, particulate urea sulfur fertilizer wherein the sulfur has particle sizes of smaller than about 100 micron. The process comprises passing molten urea and molten sulfur through a mixing device at a temperature above the melting points to produce a finely divided sulfur dispersed in urea with the molten sulfur added in amounts sufficient to produce said urea sulfur fertilizer, maintaining a pressure drop across said mixing device of at least about 200 kPa to form a homogenized melt of urea sulfur, and solidifying said homogenized melt by prilling or agglomeration.

Manufacture of urea sulfur fertilizer

A process for the production of granular sulfur in a rotating drum in which molten sulfur at a temperature within the range of about 110.degree. to 160.degree. C. is sprayed in a contact zone onto a bed of moving sulfur particles and a continuous curtain of said particles and resulting particles are passed to a cooling zone prior to discharge. A countercurrent flow of substantially inert cooling gas at a temperature in the range of about 10.degree. to 50.degree. C. and containing not more than 8% by volume oxygen is introduced to the cooling zone and a portion or all of said cooling gas is passed through the contact zone. The contact and cooling zones can be formed in a single rotating drum and separated from each other by a retaining ring or formed in separate vessels. Discharge particles from the cooling zone are separated according to size and undersized particles are recycled as fines to the contact zone at a ratio of 4:1 to 2:1 of fines to product granules.

Process for granulation of sulfur

Process and apparatus for removing particulate material from a dust laden gas exhausting from the top of a prilling tower which comprises passing the dust laden gas through an aqueous scrubbing liquid spray and thence through a filter onto which the scrubbing liquid spray impinges in co-current flow with the gas, thus maintaining the filter in a continuously wetted and irrigated state, and passing cleaned gas from the top of the tower.

Process and apparatus for cleaning prilling tower effluent

A process for recovering gaseous ammonia from liquefied ammonia stored in an underground cavern includes heating gaseous ammonia to a temperature below that at which decomposition occurs and feeding it into the liquefied ammonia in the cavern. The release of the heated gaseous ammonia in the liquefied ammonia causes conversion of some of the liquid into gaseous form, and gaseous ammonia so formed is withdrawn from the cavern.

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Trail, Canada

John T Higgins