Process for removing oil from particulate matter

Abstract

There is provided a process for removing oil from particulate matter comprising mixing an aqueous slurry of the particulate matter with at least one stream of water applied at a pressure of from 0.5 to 100 Mpa, wherein the one or more high pressure water streams expand adiabatically when mixed with the aqueous slurry.

1 . A process for removing oil from particulate matter comprising mixing an aqueous slurry of the particulate matter with at least one stream of water applied at a pressure of from 0.5 to 100 MPa, wherein the at least one high pressure water stream expands adiabatically when mixed with the aqueous slurry. 
   
   
       2 . A process as claimed in  claim 1 , wherein the particulate matter comprises mill scale, tank bottoms, sand, silt, railway ballast, sludge, glass or a mixture thereof. 
   
   
       3 . A process as claimed in  claim 1 , wherein the particulate matter to be treated comprises from 0.1 to 30% by weight oil. 
   
   
       4 . A process as claimed in  claim 1 , wherein the aqueous slurry comprises 3 to 35% by volume particulate matter. 
   
   
       5 . A process as claimed in  claim 1 , further comprising separating the particulate matter from the liquid phase after the step of mixing with the at least one high pressure water stream. 
   
   
       6 . A process as claimed in  claim 5 , wherein the particulate matter comprises less than 1,000 ppm by weight oil after separation from the liquid phase. 
   
   
       7 . A process as claimed in  claim 1 , wherein the high pressure water is mixed with the aqueous slurry in from 6 to 18 streams. 
   
   
       8 . A process as claimed in  claim 7 , wherein the water streams are applied to the aqueous slurry through nozzles having a total spraying surface area of from 0.2 to 10 mm 2 . 
   
   
       9 . A process as claimed  claim 1 , wherein the at least one high pressure water stream is mixed with the aqueous slurry as it is passed through a pipe having a diameter of from 100 to 250 mm. 
   
   
       10 . A process as claimed in  claim 9 , wherein the flow rate of the aqueous slurry through the pipe is from 75 to 200 m 3  per hour. 
   
   
       11 . A process as claimed in  claim 9 , wherein the at least one high pressure water stream is projected into the pipe containing the aqueous slurry in the direction of flow of the aqueous slurry and at an angle of 22 to 40 degrees to the axis of the pipe. 
   
   
       12 . A process as claimed in  claim 9 , wherein the at least one high pressure water stream is projected into the pipe containing the aqueous slurry in the direction of flow of the aqueous slurry through nozzles having  3  separate sub-nozzles, the central sub-nozzle projecting a stream at an angle of from 22 to 40 degrees to the axis of the pipe, and the other two nozzles projecting streams at an angle of from 5 to 15 and from 45 to 50 degrees to the axis of pipe respectively. 
   
   
       13 . A process as claimed in  claim 1 , wherein at least one of surfactants or chelating agents are added to the aqueous slurry of particulate matter before it is mixed with the at least one high pressure water stream. 
   
   
       14 . A process as claimed in  claim 13 , wherein the surfactants are added to produce a concentration of from 1,250 ppm to 5,000 ppm by volume before the step of mixing with the high pressure water.