It is necessary to inhibit a formation of basic cupric carbonate depending on a certain condition of the reaction.

It is difficult to obtain a high purity of cupric carbonate, if not.

BACKGROUND ART Waste liquid of PCB corrosion containing cupric chloride can be used to prepare cupric sulfate by an addition of cupric sulfate or to prepare cupric oxide by an addition of NaOH

because it contains 10 to 12% of copper and 10 to 15% of HC1.

The present inventors had developed a process for producing cupric carbonate from waste liquid of PCB corrosion containing cupric chloride on the basis of the above technical background.

DISCLOSURE OF THE INVENTION The present invention provides a process for converting basic cupric carbonate into cupric carbonate which comprises adding a certain content of cupric oxide (CuO) to waste liquid of PCB corrosion containing cupric chloride to remove free HCl, adding a neutralizing agent such as sodium carbonate or sodium bicarbonate thereto to obtain cupric carbonate and sodium chloride and injecting carbonic acid gas into the solution..

The present invention will be explained below in more detail by reference to the attached drawings.

A content of cupric oxide (CuO) is added to waste liquid of PCB corrosion containing cupric chloride (1) to remove free HC1, sodium carbonate solution (2) is added thereto for neutralizing, the obtained liquid containing basic cupric carbonate is forced to circulate with pumps P1, P2 and P3 under stirring of a stirrer (4), a high pressure of carbonic acid gas is injected to a inlet of pump P1, and then the liquid is continuously circulated in maintaining an average pressure

of 7 kg/cm2 by the control of a supplying pressure of carbonic acid gas (1) with a valve to induce a combination in solution of a basic cupric carbonate (Cu (OH) 2) and carbonic acid (H2CO3), to obtain cupric carbonate.

The reaction formula is as follows; Cu (OH) 2 + H2CO3-> CuCO3 + 2H20 BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows an example of an apparatus for producing cupric carbonate from waste liquid of PCB corrosion.

BEST MODE FOR CARRYING OUT OF THE INVENTION The present invention will be explained below in more detail by reference to Examples, but the invention should not be construed as being limited to these Examples in any way.

Example 1 1000 kg of PCB corrosion waste liquid containing 10% of copper content are added to a container having a volume of 3000 Under stirring, 60kg of cupric oxide are added thereto to remove free HC1 and subjected to an addition of sodium carbonate in order to adjust a pH of 8 to 9 to obtain a solution containing basic cupric carbonate and cupric carbonate. The solution is carried to a vessel of the apparatus according to the present invention. Carbonic acid gas is dispersedly provided thereto at a speed of 50 kg per

hour keeping a pressure of 7 kg/cm by the pumps PI, P2 and P3, and reacted for 3 hours to produce 295 kg of cupric sulfate.

Example 2 The same procedure as in Example 1 was conducted, except that sodium bicarbonate was used instead of sodium carbonate.

As a result, 298 kg of cupric sulfate were produced.

INDUSTRIAL APPLICABILITY The present invention has advantages that carbonic acid gas is finely crushed to a molecular unit. In the present invention, it is possible to produce cupric carbonate having a high purity because fine particles of basic cupric carbonate is combined with carbonic acid gas by a pressure of 7 kg/cm2 due to the formation of carbonic acid. According to the present invention, cupric carbonate which is provided as a mineral for an animal feed is produced industrially in a great quantity since a pressure and breaking to fine particles are effectively controlled by the appropriate apparatus such as pumps and an injector of carbonic acid gas.