PREPARATION OF ALKALI SALT SOLUTIONS
A process of preparing an alkali salt solution for the production of catalysts or promoters of catalysts, the process comprising the steps of: (i) Passing a solution containing a mixture of potassium, rubidium and caesium sulfates through an evaporative crystallisation step to obtain a potassium containing salt, and a solution comprising rubidium and caesium sulfate; (ii) Further evaporative crystallisation of the liquid product of step (i) to obtain a rubidium containing salt and a solution enriched in caesium sulfate; and (iii) Mixing one or more of the obtained salts and the solution at a desired ratio to prepare the alkali salt solution.
1 - 18 . (canceled)
19 . A process of preparing an alkali salt solution for the production of catalysts or promoters of catalysts, the process comprising the steps of:
(i) passing a solution containing a mixture of potassium, rubidium and caesium sulfates through an evaporative crystallisation step to obtain a potassium containing salt, and a solution comprising rubidium and caesium sulfate;
(ii) further evaporative crystallisation of a liquid product produced by step (i) to obtain a rubidium containing salt and a solution enriched in caesium sulfate; and
(iii) mixing one or more of the obtained salts and the solution of step (ii) at a desired ratio to prepare an alkali salt solution,
wherein the alkali salt solution of step (iii) is used as a catalyst or as a promoter in the manufacture of a catalyst.
20 . The process of claim 19 , wherein the potassium, rubidium and caesium containing solution of step (i) is a co-product of a process for the recovery of lithium from lepidolite.
21 . The process of claim 19 , wherein the potassium containing salt is potassium sulfate.
22 . The process of claim 19 , wherein the rubidium containing salt is rubidium sulfate.
23 . The process of claim 22 , wherein the rubidium sulfate is further treated to yield rubidium carbonate or rubidium hydroxide.
24 . The process of claim 19 , wherein one of the solutions of steps (i) or (ii) is further treated to yield caesium carbonate or caesium hydroxide.
25 . The process of claim 19 , wherein the catalyst is a vanadium pentoxide (V 2 O 5 ) catalyst.
26 . The process of claim 25 , wherein the vanadium pentoxide catalyst is used in the oxidisation of sulfur dioxide (SO 2 ) to sulfur trioxide (SO 3 ).
27 . The process of claim 19 , wherein the process produces a potassium sulfate product that is in turn utilised in fertilisers.
28 . The process of claim 19 , wherein the alkali sulfate mixture is created with a ratio of alkali metals determined by an intended catalyst application.
29 . The process of claim 19 , wherein the composition of the solution containing a mixture of potassium, rubidium and caesium sulfates of step (i) is represented by the generic formula M 2 SO 4 , where M represents the alkali metals present and is equal to A+B+C, where A equals the molar concentration of potassium, B equals the molar concentration of rubidium, and C equals the molar concentration of caesium.
30 . The process of claim 29 , wherein the concentration of each of A, B and C is varied from about 0.1 to 0.8 while the sum M equals 1.
31 . The process of claim 19 , wherein the alkali salt solution of step (iii) is used directly in the catalyst manufacture process without the need to combine dried individual salts to achieve a desired composition.
32 . The process of claim 19 , wherein the alkali salt solution of step (iii) is supported on a support for the production of the catalyst.
33 . The process of claim 19 , wherein the alkali salt solution of step (iii) is provided in the form of hydroxide and carbonate, and is supported on a ZrO 2 /SiO 2 support for the production of the catalyst.
34 . The process of claim 33 , wherein the catalyst is used for condensation of formaldehyde with alkyl esters or acids to produce ethylenically unsaturated esters or acids.
35 . The process of claim 33 , wherein methyl propionate is used to produce methyl methacrylate and methacrylic acid.
36 . A process of preparing an alkali salt solution that is used in the production of catalysts or promoters of catalysts, the process comprising the steps of:
(i) passing a potassium, rubidium and caesium containing solution to a crystallisation step to obtain a potassium rich salt, and a solution comprising rubidium and caesium;
(ii) further evaporative crystallisation of a liquid product produced by step (i) to obtain a rubidium rich salt and a solution enriched in caesium sulfate; and
(iii) mixing one or more of the obtained salts and the solutions of steps (i) and (ii) at a desired ratio to prepare an alkali salt solution,
wherein the potassium, rubidium and caesium containing solution of step (i) is a co-product of a lithium recovery process.
37 . A catalyst produced by the process set forth in claim 36 .
38 . A promoter of catalysts produced by the process set forth in claim 36