The present invention relates to a process for the separation of strong acid from its salts. In said process, a strong acid salt is reacted with organic weak base (OWB) in the presence of a hydrophilic solvent and CO.sub.2. The cation of the strong acid salt is precipitated to produce a carbonate/bicarbonate salt and the strong acid form a liquid salt with the OWB. The above process is performed in a solution comprising both the strong acid salt and the WBO. In the next step, the strong acid is released from its OWB liquid salt and the OWB is returned to a previous step.

A method for recovering and purifying a waste sulfuric acid solution includes steps of: adding a coupling agent (m) to the waste sulfuric acid solution, and mixing uniformly to obtain a mixture (a); adding a coupling agent (n) to the mixture (a), and mixing uniformly to obtain a mixture (b); and adding a synergistic agent to the mixture (b), thoroughly stirring and filtering to obtain a purified sulfuric acid solution. The method adds the coupling agent and the synergistic agent to the waste sulfuric acid, and a removal rate of the heavy metal ions in the waste sulfuric acid can reach 99%. The purified sulfuric acid solution can be recycled. The method is simple to operate, and can remove a wide variety of heavy metal ions such as copper, zinc, lead, mercury, nickel, iron, cadmium and manganese in the waste sulfuric acid.

A method for recovering and purifying a waste sulfuric acid solution includes steps of: adding a coupling agent (m) to the waste sulfuric acid solution, and mixing uniformly to obtain a mixture (a); adding a coupling agent (n) to the mixture (a), and mixing uniformly to obtain a mixture (b); and adding a synergistic agent to the mixture (b), thoroughly stirring and filtering to obtain a purified sulfuric acid solution. The method adds the coupling agent and the synergistic agent to the waste sulfuric acid, and a removal rate of the heavy metal ions in the waste sulfuric acid can reach 99%. The purified sulfuric acid solution can be recycled. The method is simple to operate, and can remove a wide variety of heavy metal ions such as copper, zinc, lead, mercury, nickel, iron, cadmium and manganese in the waste sulfuric acid.

A method for manufacturing high purity sulfuric acid is provided. A mixed solution subsequently undergoes a first preheating step, a second preheating step, a distilling step and an evaporating step to remove peroxide, water, oxygen and insoluble impurities, so as to obtain the first gas containing sulfur trioxide, sulfuric acid and hydrogen oxide. And then, the sulfur trioxide is absorbed by a sulfuric acid solution, thereby forming the high purity sulfuric acid.

A method for manufacturing high purity sulfuric acid is provided. A mixed solution subsequently undergoes a first preheating step, a second preheating step, a distilling step and an evaporating step to remove peroxide, water, oxygen and insoluble impurities, so as to obtain the first gas containing sulfur trioxide, sulfuric acid and hydrogen oxide. And then, the sulfur trioxide is absorbed by a sulfuric acid solution, thereby forming the high purity sulfuric acid.

A method for manufacturing high purity sulfuric acid is provided. A mixed solution subsequently undergoes a first preheating step, a second preheating step, a distilling step and an evaporating step to remove peroxide, water, oxygen and insoluble impurities, so as to obtain the first gas containing sulfur trioxide, sulfuric acid and hydrogen oxide. And then, the sulfur trioxide is absorbed by a sulfuric acid solution, thereby forming the high purity sulfuric acid.

A method for separating arsenic and heavy metals in an acidic washing solution which contains both arsenic and heavy metal, more particularly in a washing solution which is formed in copper smelting and contains sulphuric acid, comprises a separation process section, in which arsenic and at least one primary heavy metal are separated from one another. The separation process section comprises a processing step, in which hydrogen peroxide H2O2 is added to the washing solution, and the separation process section comprises a precipitation stage, in which the washing solution is admixed with a sulphide precipitation reagent, causing the at least one primary heavy metal to precipitate in the form of a metal sulphide. The processing step in this system is carried out before the precipitation stage.