Formulations containing a phosphide for use in the controlled generation of phosphine
Inactive Publication Date: 2001-08-09
COMMONWEALTH SCI & IND RES ORG
View PDF0 Cites 4 Cited by
- Summary
- Abstract
- Description
- Claims
- Application Information
AI Technical Summary
Problems solved by technology
Such techniques, however, cannot be guaranteed to supply phosphine to all regions of the bulk stored grain to eradiate weevils and other unwanted grain pests.
In addition, when these traditional techniques are used, there is no control over the concentration of phosphine in the grain after the phosphide formulation has been added, and there is no possibility of regulating the phosphine concentration / time regime in the bulk storage to be most effective.
Although this approach to the fumigation of grain is regarded as the most efficient, its major disadvantage is the need to guarantee a supply of expensive cylinders of the gas mixture to the treatment site.
There is one significant problem with the use of phosphine.
When its concentration in air reaches certain values, the gas mixture is flammable and potentially explosive.
Other potential problems with the use of phosphine are the toxicity of phosphine to mammals when the phosphine is present in high concentrations, and the exothermic nature of the hydrolysis reaction which produces the phosphine.
In addition, with the fumigation regimes now being employed (for example, maintaining low phosphine concentrations for long periods), it is possible that the on-site phosphine generators may be left unattended for a considerable time.
Thus on-site phosphine generators, with their attendant fire or explosion risk, have been unattractive for long term fumigation operations.
Method used
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View moreImage
Smart Image Click on the blue labels to locate them in the text.
Smart ImageViewing Examples
Examples
Experimental program
Comparison scheme
Effect test
Embodiment Construction
[0051] To evaluate phosphide formulations prepared in accordance with the present invention, quantities of technical grade aluminium phosphide were mixed with various water-immiscible compounds, or mixtures of water-immiscible compounds, and the resultant formulations were dispersed in water or were exposed to moist air in a variety of experimental conditions. Initially, the aluminium phosphide was ground and only aluminium phosphide particles which passed through a sieve having a mesh size of 250 .mu.m were used in the formulations. However, later samples of the formulations were produced using aluminium phosphide which contained particles having a diameter greater than 250 .mu.m. In addition, a small number of formulations were prepared by dispersing pellets of aluminium phosphide (marketed under the trade mark PHOSTOXIN) in selected water-immiscible compounds. All formulations tested yielded phosphine in a controlled manner when the formulations were placed in a water bath. In th...
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More PUM
Login to View More Abstract
A formulation for use in the controlled generation of phosphine comprises a mixture of a particulate phosphide and a water-immiscible compound. The water-immiscible compound is paraffin oil, petroleum jelly, a mixture of these materials or a wax having a melting point in the range 35° C. to 65° C. The phosphide comprises from 65 to 85 per cent (by weight) of the formulation. Such a formulation can be added progressively to water in a reaction chamber. Alternatively, the formulation can be packaged in a water-impermeable container from which a region can be removed to expose the formulation to water vapor in a gas flowing past the container. The water or the water vapor reacts with the phosphide particles as they become exposed to form phosphine. The phosphine, mixed with a carrier (usually air), may be fed into a duct connected to a grain silo, for fumigation of grain stored in the silo.
Description
CROSS-REFERENCE[0001] This application is a continuation-in-part of U.S. patent application Ser. No. 08 / 971,247 filed Nov. 17, 1997, which was a continuation of U.S. patent application Ser. No. 08 / 343,609 (now abandoned), filed Jan. 6, 1995, which was the U.S. national phase of International patent application No. PCT / AU93 / 00270, which was filed on Jun. 4, 1993.[0002] This invention concerns formulations for use in the generation of phosphine. These formulations are particularly suited for the production of phosphine for use in the fumigation of grain and similar particulate commodities stored in bulk, but they are not limited to that purpose.BACKGROUND TO THE INVENTION[0003] Phosphine (PH.sub.3) has been a preferred gaseous fumigant for stored grain and similar particulate commodities because any residue of the fumigant will be lost or oxidised to a harmless phosphate when the grain or other commodity is processed to produce a food. Examples of the fumigation of grain with phosphin...
Claims
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More Application Information
Patent Timeline
Login to View More IPC IPC(8): A01M17/00A01N59/26C01B25/06
CPCA01M17/008A01N59/26C01B25/06A01N25/18A01N2300/00
InventorWATERFORD, COLIN JOSEPHWINKS, ROBERT GORDON
OwnerCOMMONWEALTH SCI & IND RES ORG