Process for making cupric hydroxide

In one exemplar embodiment, the present invention comprises a method of making cupric hydroxide that comprises the steps of preparing a suspension of insoluble copper oxychloride in aqueous medium, mixing sodium lignosulfonate into the copper oxychloride suspension for more uniformly dispersing the copper oxychloride particles in the aqueous medium agitating the copper oxychloride suspension and added sodium lignosulfonate until a desired viscosity is obtained, adding sodium hydroxide to the copper oxychloride suspension for reacting with the copper oxychloride to form cupric hydroxide, and recovering the cupric hydroxide.

BACKGROUND OF THE INVENTION 
This invention relates to a process for making a stable copper (cupric) 
hydroxide by means of reacting sodium hydroxide with copper oxychloride. 
DESCRIPTION OF THE PRIOR ART 
There are numerous ways disclosed in the prior art for making cupric 
hydroxide. One technique uses a copper sulfate solution reacted with 
ammonia to form cupric hydroxide and a compound containing the sulfate 
radical for particular use in the preparation of a cuprammonium cellulose 
solution in making rayon as disclosed in U.S. Pat. No. 2,758,013. Others 
disclose use of a copper sulfate solution reacted with ammonia and then 
with an alkali metal hydroxide (such as sodium hydroxide) to precipitate 
non-soluble cupric hydroxide as shown in U.S. Pat. Nos. 1,800,828; and 
1,867,357. Another variation of the ammonia reaction processes is the 
reaction under anhydrous conditions of an inorganic copper salt, ammonia 
and a lower alkanol solvent for the inorganic copper salt to form a 
resulting complex which is then reacted with an alkali metal hydroxide, 
with the resulting complex decomposed under vacuum to obtain cupric 
hydroxide as disclosed in U.S. Pat. No. 3,956,475. It is known that 
stable, separable cupric hydroxide cannot generally be made by direct 
reaction between copper sulphate and sodium hydroxide. The combination of 
these two chemicals results in the formation of blue cupric hydroxide in a 
sludge form but which rapidly decomposes to black cupric oxide. U.S. Pat. 
No. 1,920,053 discloses a process for making cupric hydroxide from copper 
sulfate and excess sodium hydroxide carried out at low temperatures (below 
10.degree. C.) to help overcome this problem. Another process for making 
cupric hydroxide is disclosed in U.S. Pat. No. Re. 24,324 in which 
trisodium phosphate is reacted with copper sulfate to form copper sodium 
phosphate which is in turn reacted with sodium hydroxide to precipitate 
cupric hydroxide. 
All of the prior art processes are too complex or expensive or fail to 
produce a stable form of cupric hydroxide suitable for large scale 
production, particularly for use as an agricultural fungicide and 
bactericide. 
SUMMARY OF THE INVENTION 
The present invention remedies the problems of the prior art by providing a 
process or method of making cupric hydroxide that comprises the steps of 
preparing a suspension of insoluble copper oxychloride in an aqueous 
medium, mixing sodium lignosulfonate into the copper oxychloride 
suspension for more uniformly dispersing the copper oxychloride particles 
in the aqueous medium, agitating the copper oxychloride suspension and 
added sodium lignosulfonate until a desired viscosity is reached, adding 
sodium hydroxide to the copper oxychloride suspension for reacting with 
the copper oxychloride to precipitate cupric hydroxide, the sodium 
lignosulfonate further acting to stabilize the cupric hydroxide formed, 
and recovering the cupric hydroxide. The cupric hydroxide made according 
to this process is extremely stable, is the result of a one-reaction 
process, and enables a manufacturer to produce cupric hydroxide in large 
bulk quantities at lower prices than presently possible.

BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The present process for making stable cupric hydroxide, which is 
particularly suited for large scale production in manufacturing 
agricultural fungicides and bactericides, includes the following basic 
steps: 
Step 1--Prepare a suspension of insoluble copper oxychloride 
(CuCl.sub.2.3Cu(OH).sub.2) in an aqueous medium of any convenient 
concentration and place in a suitable mixing vessel; 
Step 2--Add sodium lignosulfonate (approximately 1% by weight) to the 
copper oxychloride suspension and agitate until the mixture achieves a 
desired viscosity as judged by when it takes on a "smooth" or "creamy" 
appearance as judged by eye; 
Step 3--As rapidly as possible, add a sodium hydroxide solution (NaOH) of 
50.0% concentration and containing an excess quantity of sodium hydroxide 
then stoichiometrically necessary to react with the copper oxychloride to 
form cupric hydroxide to the mixture of sodium lignosulfonate and copper 
oxychloride suspension and continue agitation until the resulting reaction 
slurry (comprising a suspension of cupric hydroxide in the resultant 
reaction) changes color from light blue or gray-blue to a dark blue (as 
judged by eye and memory); 
Step 4--Stop agitation and collect the cupric hydroxide (Cu(OH).sub.2) from 
the slurry by vacuum filtration. The above process is carried out at 
normal room temperatures. 
The collected cupric hydroxide filter cake is washed with fresh water until 
the pH is lowered to approximately 8. The washed dark blue filter cake may 
then be dried in any convenient manner to obtain a dried granular form of 
cupric hydroxice. The resultant aqueous filtrate or mother liquor, 
primarily a sodium chloride colution (NaCl) with remaining sodium 
lognosulfonate, is disposed of as waste. 
In preparing large quantities of cupric hydroxide in the batch process, it 
has been found that certain preferred quantities and concentrations of 
starting materials yield the best results. For example, if it is desired 
for the above process to yield one ton of cupric hydroxide, then the 
copper oxychloride suspension in an aqueous medium should preferably be 
9120 liters and have a concentration of 98 grams per liter. The pH range 
desired is 6-7. The quantity of sodium lignosulfonate added would be 11 
kilograms. The sodium hydroxide solution should be a 50% concentration 
containing a maxium of 410 kilograms of the sodium hydroxide dry base. 
While varying percentages of excess sodium hydroxide than that necessary 
to stoichiometrically react with the copper oxychloride to form cupric 
hydroxide may be used, it has been found that large excess percentages, 
for example 80.0%, are preferable to accelerate the reaction rate and form 
the desired size of cupric hydroxide particles of crystals in suspension. 
The sodium lignosulfonate is a metallic sulfonate salt made from the lignin 
of sulfite pulp-mill liquors and has molecular weights ranging from 1,000 
to 20,000. The lignosulfonate does not chemically react with copper 
oxychloride or sodium hydroxide, but is added to the copper oxychloride 
suspension to act as a dispersing agent to more uniformly disperse the 
suspended insoluble copper oxychloride particles in the aqueous medium for 
enhancing the resultant chemical reaction of the copper oxychloride and 
sodium hydroxide. It is also believed that tht sodium lignosulfonate acts 
as a stabilizer of the resultant cupric hydroxide formed and prevents its 
decomposition to useless cupric oxide by preventing water loss from the 
cupric hydroxide. 
There is no exact formula for the starting material copper oxychloride, but 
it has been found convenient to use the following formulation: 
EQU CuCl.sub.2.3Cu(OH).sub.2 
which when reacted with the sodium hydroxide provides: 
EQU CuCl.sub.2.3Cu(OH).sub.2 +2NaOH.fwdarw.4Cu(OH).sub.2 +2NaCl 
of course, other convenient copper oxychloride formulas may be used. In the 
process Step 3 above described in making the large quantity (one ton) of 
cupric hydroxide, the time period for agitation of the combined sodium 
hydroxide solution and copper oxychloride suspension and sodium 
lignosulfonate to effect the desired "dark blue" color is approximately 20 
minutes. 
The dried granular cupric hydroxide is formulated for final use as an 
agricultural fungicide or bactericide by mixing with sodium lignosulfonate 
(7.0% by weight), a suitable wetting agent (such as nonyl phenol 
exhoxilate or other suitable agent) (less than 1.0% by weight) and calcium 
carbonate (about 16% by weight). The calcium carbonate is used as a filler 
to reduce the copper concentration in the final product to a maximum of 
50%. The above mixture is then pulverized in a hammer mill to a fine 
powder to form the final stable cupric hydroxide product.