Disclosed are a system and a process for preparing a refined sodium carbonate solution. The system includes a formulation tank for dissolving an industrial-grade sodium carbonate; a feeding mechanism, an outlet of which is connected to an inlet of the formulation tank; a pH regulator, the pH regulator being disposed in the formulation tank, and the feeding mechanism being connected to the pH regulator; a filtering mechanism, an inlet of which is connected to an outlet of the formulation tank; and an adsorption mechanism, an inlet of which is connected to an outlet of the filtering mechanism.

A process for preparing a powder support containing alumina and silica or their derivatives for a catalyst of a Fischer-Tropsch type reaction, including stage (a) of preparing a first reactant containing an alumina compound or precursor including a reaction for peptization of an alumina compound or precursor in the presence of an acid, to form solid particles in suspension, stage (b) of preparing a second reactant based on silicic acid and/or on a compound or precursor of silicic acid, including a controlled aging treatment of the silicic acid targeted at its polymerization up to a degree of conversion of the silicic acid of at most 70%, stage (c) of mixing the two reactants in a mixer, and the pH of the first reactant is adjusted to a value not exceeding a given maximum pH threshold.

A sulfuric acid generating system can include: a primary burn chamber; an exhaust pipe extending from the burn chamber at a first end to an opposite second end; a secondary burn chamber located between the first end and second end; and a primary venturi pump having a gas inlet coupled to an outlet at the second end of the exhaust pipe and having an aqueous media inlet and having a fluid outlet. A method of producing sulfurous acid can include: providing sulfur to the primary burn chamber; burning a first portion of the sulfur in the primary burn chamber to form a first portion of sulfur dioxide; burning a second portion of the sulfur in the secondary burn chamber to form a second portion of sulfur dioxide; and mixing the first portion and second portion of sulfur dioxide with an aqueous composition so as to produce aqueous sulfurous acid.

The disclosure pertains to an ammonium nitrate reactor with a first type static mixer in the mixing zone upstream of the tube bundle and/or a second type static mixer downstream of the tube bundle.

What is provided is stannous oxide having an -ray emission amount of 0.002 cph/cm.sup.2 or less after heating in an atmosphere at 100 C. for 6 hours. Tin containing lead as an impurity is dissolved in a sulfuric acid aqueous solution to prepare a tin sulfate aqueous solution, and lead sulfate is precipitated in the aqueous solution and removed. While stirring the tin sulfate aqueous solution from which lead sulfate has been removed, a lead nitrate aqueous solution containing lead having an -ray emission amount of 10 cph/cm.sup.2 or less is added to cause lead sulfate to be precipitated in the tin sulfate aqueous solution, and simultaneously the tin sulfate aqueous solution is circulated while removing the lead sulfate from the aqueous solution. A neutralizing agent is added to the tin sulfate aqueous solution to collect stannous oxide.