Abstract:
A process is described for the comminution of a solid material in the presence of a saturated solution of the solid in a liquid in which the solid has a solubility greater than 1%, and also in the presence of an additive dissolved in the saturated solution which can at least partially inhibit regrowth at crystal surfaces of the solid material. The process is of particular interest for the comminution of water-soluble salts in the presence of their saturated aqueous solutions and may be employed to make, inter alia, improved slurry explosives and fluid fertilizer compositions.
Abstract:
A fluid fertilizer composition based essentially on potassium chloride and an ammonium phosphate prepared by a process which comprises comminuting a solid substance containing potassium chloride and ammonium phosphate by grinding in the presence of a saturated solution of solid in a liquid in which the solid has a solubility greater than 1% by weight, the mixture of the solution and the solid being in fluid condition with the solid being a separate phase during grinding and the solution having dissolved therein an additive which is a crystal growth inhibitor for the solid whereby crystal growth is inhibited at both existing crystal surfaces and new crystal surfaces created by the breaking down of relatively coarse particles.
Abstract:
An aqueous slurry explosive blasting composition comprising an aqueous suspension of water-soluble crystalline oxidizing salt consisting predominantly of ammonium nitrate, which salt has been comminuted in a saturated aqueous solution in the presence of a water-soluble crystal-growth inhibiting surfactant having a hydrophobic portion and a hydrophilic portion in its molecule, in intimate admixture with liquid water-immiscible hydrocarbon fuel sensitizer. The surfactant maintains the oxidizer salt in a finely divided state and also ensures that the liquid hydrocarbon remains uniformly distributed throughout the explosive mass as a stable coating of droplets on the salt particles thereby enhancing the explosive sensitivity of the composition. The preferred fuel is diesel oil and preferred surfactants include sodium carboxymethyl cellulose, long chain aliphatic amines, polyacrylic acids, sulphonated nuclear aromatic compounds, sulphonated dyes, sulphonated polymers and long chain alcohol sulphonates and phosphonates.
Abstract:
Water-soluble crystalline material which has been comminuted in a saturated aqueous solution of the material in the presence of a water-soluble crystal-growth inhibitor having a hydrophobic portion and a hydrophilic portion in its molecular structure is mixed with a deflocculant which inhibits the interaction of the hydrophobic molecular portions whenever the comminuted solid is suspended in water. The viscosity of aqueous suspensions of comminuted solid is thereby stabilized.The invention is especially beneficial in the preparation of aqueous suspensions of finely comminuted ammonium nitrate for use in slurry blasting explosives.With crystal-growth inhibitors such as water-soluble polysaccharide derivatives, long chain aliphatic amines, polyacrylic acids, sulphonated nuclear aromatic compounds, sulphonated dyes or sulphonated polymers the preferred deflocculant, which should be different from the crystal-growth inhibitor, may include water-soluble polysaccharide derivatives, polyacrylic acid, polyvinyl pyrrolidone, sodium lignosulphonate and/or a salt of a condensate of naphthalene sulphonic acid with formaldehyde.
Abstract:
A slurry composition based essentially on ammonium nitrate, prepared by a process which comprises comminuting solid substance containing ammonium nitrate by grinding in the presence of a saturated solution of solid in a liquid in which the solid has a solubility greater than 1% by weight, the mixture of the solution and the solid being in fluid condition with the solid being a separate phase during grinding and the solution having dissolved therein an additive which is a crystal growth inhibitor for the solid whereby crystal growth is inhibited at both existing crystal surfaces and new crystal surfaces created by the breaking down of relatively coarse particles.
Abstract:
A powder explosive composition comprising particulate inorganic oxidizing salt, finely divided metal sensitizer and, optionally additional fuel consisting of discrete granules containing oxidizing salt and sensitizing metal coated with a tough, cohesive, resilient gelled solution of the oxidizing salt, the amount of the coating being insufficient to form a continuous gelled phase. The composition is more water resistant, less dusty and less sensitive to friction and impact than the metal sensitized powder compositions of the prior art.
Abstract:
A method of forming a composite carbon fibres and synthetic plastics material by embodying the fibres in a matrix of the synthetic plastics material. In the interfacial region of the carbon fibres and synthetic plastics material an elastomeric resin is provided which is compatible with the synthetic plastics material used for the matrix to minimise the tendency for cracks to initiate at the interface.