A method for recovery of aluminum hydroxide Al(OH).sub.3 from an aluminum enriched water/wastewater treatment sludge is disclosed. The method includes the steps of: adding a hydrated lime slurry to the aluminum enriched water/wastewater treatment sludge to form an alkaline sludge; adding sodium carbonate Na.sub.2CO.sub.3 to the alkaline sludge to form a Na.sub.2CO.sub.3 treated sludge; forming a first supernatant from the Na.sub.2CO.sub.3 treated sludge of step b) containing NaAl(OH).sub.4; introducing CO.sub.2 to the first supernatant to form a precipitate of Al(OH).sub.3 and a second supernatant containing NaHCO.sub.3; and recycling at least a portion of the NaHCO.sub.3 from the second supernatant back to the alkaline sludge of step a).

A catalyst comprising a calcined oxide matrix which is mainly alumina and an active phase comprising nickel, said active phase being at least partially co-mixed within said calcined oxide matrix which is mainly alumina, the nickel content being in the range 5% to 65% by weight of said element with respect to the total mass of catalyst, said active phase not comprising any metal from group VIB, the nickel particles having a diameter of less than 15 nm, said catalyst having a median mesopore diameter in the range 12 nm to 25 nm, a median macropore diameter in the range 50 to 300 nm, a mesopore volume, measured by mercury porosimetry, of 0.40 mL/g or more and a total pore volume, measured by mercury porosimetry, of 0.45 mL/g or more. The process for the preparation of said catalyst, and its use in a hydrogenation process.

A method for recovery of aluminum hydroxide Al(OH).sub.3 from an aluminum enriched water/wastewater treatment sludge is disclosed. The method includes the steps of: adding a hydrated lime slurry to the aluminum enriched water/wastewater treatment sludge to form an alkaline sludge; adding sodium carbonate Na.sub.2CO.sub.3 to the alkaline sludge to form a Na.sub.2CO.sub.3 treated sludge; forming a first supernatant from the Na.sub.2CO.sub.3 treated sludge of step b) containing NaAl(OH).sub.4; introducing CO.sub.2 to the first supernatant to form a precipitate of Al(OH).sub.3 and a second supernatant containing NaHCO.sub.3; and recycling at least a portion of the NaHCO.sub.3 from the second supernatant back to the alkaline sludge of step a).

A supported catalyst having a calcined, predominantly aluminum, oxide support and an active phase of 5 to 65% by weight nickel with respect to the total mass of the catalyst, said active phase having no group VIB metal, the nickel particles having a diameter less than or equal to 20 nm, said catalyst having a mesopore median diameter greater than or equal to 14 nm, a mesopore volume measured by mercury porosimetry greater than or equal to 0.45 mL/g, a total pore volume measured by mercury porosimetry greater than or equal to 0.45 mL/g, a macropore volume less than 5% of the total pore volume, said catalyst being in the form of grains having an average diameter comprised between 0.5 and 10 mm. The invention also relates to the process for the preparation of said catalyst and the use thereof in a hydrogenation process.

Disclosed herein, is a process for recovering valuable metals and/or their oxides from red mud bauxite residues or similar. The process comprises: calcining a red mud residue having a pH of less than about 10 to provide a calcinated red mud residue; acid leaching the calcinated red mud residue to provide a silica rich solid component and an acid leachate; separating the silica rich solid component and the acid leachate; precipitating an iron rich solid component from the acid leachate; and separating the precipitated iron rich solid component from the acid leachate to provide an aluminium rich liquor.

A process for the preparation of an alumina in the form of beads with a sulphur content in the range 0.001% to 1% by weight and a sodium content in the range 0.001% to 1% by weight with respect to the total mass of said beads is described, said beads being prepared by shaping an alumina gel having a high dispersibility by drop coagulation. The alumina gel is itself prepared using a specific precipitation preparation process in order to obtain at least 40% by weight of alumina with respect to the total quantity of alumina formed at the end of the gel preparation process right from the first precipitation step, the quantity of alumina formed at the end of the first precipitation step possibly even reaching 100%. The invention also concerns the use of alumina beads as a catalyst support in a catalytic reforming process.

The present invention describes a process for hydrocracking at least one hydrocarbon feed in which at least 50% by weight of the compounds have an initial boiling point of more than 300 C. and a final boiling point of less than 540 C. using at least one catalyst comprising at least one metal from group VIB and/or at least one metal from group VIII of the periodic classification of the elements and a support comprising at least one zeolite containing at least one series of channels the opening of which is defined by a ring containing 12 oxygen atoms (12MR), and at least one binder, said support being prepared from a highly dispersible alumina gel, said hydrocracking process being operated at a temperature in the range 200 C. to 480 C., at a total pressure in the range 1 MPa to 25 MPa, with a ratio of the volume of hydrogen to the volume of hydrocarbon feed in the range 80 to 5000 litres per litre and with an hourly space velocity (HSV), defined as the ratio of the volume flow rate of liquid hydrocarbon feed to the volume of catalyst charged into the reactor, in the range 0.1 to 50 h.sup.1.

The present invention relates to the field of solid materials for adsorption of lithium. In particular, the present invention relates to a novel method for preparing a crystallized and shaped solid material, preferably as extrudates, of formula LiX.sub.x.2Al(OH).sub.3, nH.sub.2O with n being comprised between 0.01 and 10, x being equal to 1 when X is an anion selected from among chloride, hydroxide and nitrate anions, and x being equal to 0.5 when X is an anion selected from among sulfate and carbonate anions, comprising a step a) for precipitation of boehmite under specific temperature and pH conditions, at least one shaping step, preferably by extrusion, said method also comprising a final hydrothermal treatment step, the whole giving the possibility of increasing the adsorption capacity for lithium as well as the adsorption kinetics of the materials obtained as compared with the materials of the prior art when the latter is used in a method for extracting the lithium from saline solutions.

A novel alumina gel is described having an elevated dispersibility index, and in particular a dispersibility index greater than 70%, a crystallite size between 1 and 35 nm, and a sulphur content between 0.001% and 2% by weight, and a sodium content between 0.001% and 2% by weight, the weight percentages being expressed in relation to the total mass of alumina gel.

The present invention also discloses the method for preparing said gel comprising at least one step of precipitating at least one aluminium salt, at least one step of heating the suspension obtained and a final heat treatment step for forming the alumina gel.

The invention relates to the preparation of a catalyst containing: a mainly aluminum oxide calcined support; a hydro-dehydrogenating active phase containing at least one metal of group VIB,
the process including:
a) a first precipitation step of at least one basic precursor and at least one acidic precursor,
b) a heating step,
c) a second precipitation step by addition to the suspension of at least one basic precursor and at least one acidic precursor,
d) a filtration step;
e) a drying step,
f) a moulding step,
g) a heat treatment step;
h) an impregnation step of the hydro-dehydrogenating active phase on the support obtained in the step g).