A method for producing an additive for reclaiming oil from a fluid product stream and a treated silica with controlled hydrophobicity for use in the method are disclosed. The method includes the steps of providing silica or silicate with a particle size of between 3.0 m to 20 m, the silica or silicates having an agglomerate size of between 10 m to 100 m and being chosen to achieve the desired particle-size range and with a controlled level of hydrophobicity; treating the silica or silicate with a silicone or silane to make it hydrophobic; and controlling the hydrophobicity of the silica or silicate by varying the temperature and treatment time of the silica or silicate, amount of a treating material used to treat the silica or silicate, and the molecular weight of the treating material. The additive and related method improves oil extraction and concentration from a fluid product stream.

Porous amorphous silica can be obtained from siliceous plant matter containing non-siliceous inorganic substances. The siliceous plant matter is soaked in an aqueous solution which includes a chelating agent. The chelating agent is present in an amount which helps to extract at least some of the non-siliceous inorganic matter. The aqueous solution is then separated from the siliceous plant matter. Beneficial properties are imparted to the siliceous plant matter by controlling the amount of at least one preselected non-siliceous inorganic substance in the siliceous plant matter. At the end of the process, the siliceous plant matter is heat treated in the presence of oxygen at a temperature to produce the resulting amorphous silica having the beneficial properties.

Spherically-shaped silica can include a precipitated silica powder having a d.sub.50 particle size selected within a range of greater than 20 m and up to 80 m, a di-octyl adipate oil absorption selected within a range of from 150 ml/100 g to 500 ml/100 g, an average circularity selected within a range of from 0.70 to 1.0, and an angle of repose, of less than 30. A process of preparing spherically-shaped silica powder is also included.

The invention relates to a process for producing a silicate from a plant ash comprising crystalline silica. The process comprises reacting said plant ash with a base in the presence of an additive which is a salt comprising a multivalent anion. The invention also relates to a silicate obtainable from said process and to a process for preparing a precipitated silica from said silicate. The invention also concerns a reaction mixture which can be used for said processes.

A process for recycling glass from screens deriving from the disposal of cathode-ray tube television sets with quantitative recovery of the lead in metal form, is described.

A process for preparing precipitated silica comprising a reaction of a silicate with an acidifying agent to obtain a suspension of precipitated silica (S1), followed by a separation step to obtain a cake, a disintegration step of said cake to obtain a suspension of precipitated silica (S2), and a drying step of this suspension, wherein the disintegration step is performed by mixing using a twin-screw mixer or by extrusion.

The present invention relates to a method of purifying strong acids or strongly acidic media to remove di- and higher valent metal ions, which can be used within the context of the production of high-purity silica. The invention further relates to the use of special ion exchangers for carrying out the method according to the invention and the resultant high-purity silicas.

An improved beta(?)-spodumene (?LiAlSi.sub.2O.sub.6) nitric acid conversion process produces discrete lithium (Li), aluminum (Al) and silica (SiO.sub.2) materials by: (i) converting lithium nitrate, LiNO.sub.3, to lithium carbonate, Li.sub.2CO.sub.3; (ii) creating a Al-rich precipitate either by thermally decomposing aluminum nitrate, Al(NO.sub.3).sub.3, or by reacting Al(NO.sub.3).sub.3 with aqueous and/or solid ammonium carbonate, (NH.sub.4).sub.2CO.sub.3; and (iii) forming a solid SiO.sub.2-rich aluminosilicate residue by selectively leaching Li and Al from ?-spodumene. Three key reactants consumed during processingnitric acid (HNO.sub.3), ammonia (NH.sub.3), and magnesium oxide (MgO)may be regenerated internally by closed-loop chemical cycles, this feature of the process greatly improving its economics in commercial applications.

A process for preparing precipitated silica in which: (i) an stock having a concentration of alkali metal M silicate less than 20 g/L is formed; (ii) acid is added to said initial stock, until at least 50% of the amount of M.sub.2O is neutralized; (iii) silicate and acid are simultaneously added, such that the degree of consolidation is greater than 4 and at most 100; and (v) acid is added until a pH value of between 2.5 and 5.3 is obtained, wherein the acid used in at least one of the process steps is a concentrated acid.

A process for preparing precipitated silica in which: (i) an aqueous stock having a concentration of alkali metal silicate less than 20 g/L is formed; (ii) acid is added to said initial stock, until at least 50% of the amount of M.sub.2O is neutralized; (iii) silicate and acid are simultaneously added, such that the degree of consolidation is greater than 4 and at most 100; (iv) silicate and acid are simultaneously added, such that the pH of the reaction medium is between 7 and 10; (v) acid is added until a pH value of between 2.5 and 5.3 is obtained; and (vi) the reaction medium is placed in contact with acid and silicate, such that the pH is between 2.5 and 5.3, wherein the acid used in at least one of the process steps is a concentrated acid.