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The Development of Micronutrients TBCC®

 Copper in Nutrition

Most higher life forms have evolved to utilize, and to require, a wide range of mineral nutrients provided by the crust of the earth. As farming intensity has increased with associated higher yields per acre, trace minerals provided by natural processes have been depleted from soils, leading to the need for supplementation. A number of metals, including cobalt, copper, iron, manganese, molybdenum and zinc have been proven to be essential nutrients for both plants and animals (1). In animals, an inadequate supply of such essential trace minerals (ETM’s) will result in poor health and can, in the extreme, lead to death. Recent work illustrates that optimum health and performance requires more of these nutrients than just the "essential" levels needed to avoid deficiency symptoms (2).

Copper is one of the most critical of the ETM’s. In animals, it is a component in at least ten enzymes that regulate physiologic functions. One of the most vital roles for copper is in ceruloplasmin, which facilitates iron absorption, mobilization and transport throughout the body. Thus, it is essential to the most basic life support function – the transport of oxygen by hemoglobin, an iron compound (3).

Copper, and many other ETM’s, are added to feed mixtures in commercial animal production since they are not included in fertilizers for corn and soy bean production. Emphasis on bioavailability has caused a shift away from elemental or oxide forms of copper, and toward the use of copper sulfate as the predominant source in feed. Approximately 10,000 metric tons of copper is added to animal feed in the USA each year (4).

Unfortunately, while it improved bioavailability, copper sulfate also has undesirable side effects such as interaction with other ingredients in a mixture. Since copper sulfate is highly water soluble, it is hygroscopic, drawing moisture to the surface of each crystal. It is also an acidic compound, and thus a strong electron acceptor. In a mineral premix, these properties can lead to heat build up and solidification of the mixture, destroying its value. In a feed mixture, which inevitably contains 10 - 20% moisture, the copper sulfate crystal surfaces become a concentrated "hot spot" for reactions that break down labile organic compounds such as vitamins, enzymes and fats and oils (5).

Development of an Improved Copper Source

In 1992, a research project was launched by Heritage Environmental Services, LLC, Indianapolis, IN to develop a process for production of an improved animal feed ingredient. It was well known that basic copper chloride could be produced by hydrolysis of a cupric chloride solution (6). One particular basic chloride, dicopper chloride trihydroxide, with the formula Cu2(OH)3Cl, was of particular interest. Due to its inherent chemical properties – neutrality, insolubility in water, and high copper content - it was assumed that this compound would be useful as a source in animal feed if it had good bioavailability.

Also, it had been previously observed that two types of spent etching solutions used in manufacturing electronic printed wiring boards (PWB’s) could be reacted to produce a copper precipitate with the apparent empirical formula of Cu2(OH)3Cl. One of the solutions is acidic, consisting of cupric chloride and some free hydrochloric acid. The short-hand name used in the industry for this spent solution is "cupric". The other is a solution of copper tetrammine dichloride – nicknamed "ammo" in the trade.

As the research project was launched, it was clear that there were two major hurdles:
  1. The copper salt tended to form as an amorphous, gel-like precipitate with poor physical properties. As a result, the background solution of ammonium chloride could not be effectively separated from the product
  2. The solution remaining after copper precipitation contained significant residual copper in addition to various trace metals that result from etching a printed circuit - zinc, lead, tin, arsenic, antimony and chromium.
The first hurdle was attacked on two parallel fronts. The first focused on using the precipitate as an intermediate to be converted into a different copper salt in one or more additional steps. A conversion process (i.e. to the oxide or sulfate) would have added both capital and operating cost. Also, it turned out to be difficult to make a low-chloride salt without generating large volumes of waste water. Because of these drawbacks, and since good progress was occurring on the second front, this effort was truncated.

The second parallel development front pursued controlling the mechanism of formation of the copper salt. The objective was to produce a pure, crystalline product with individual particles large enough to be washed free of mother liquor. Progress was tracked with X-ray diffraction studies. These showed the early samples to be mixtures of one or more of five different copper salts. In addition to the target compound, there were significant amounts of at least four others - CuCl2·NH4Cl , Cu(NH3)2Cl2 , Cu(OH)2 and Cu3(OH)2(CO3)2. However, most samples showed that a major fraction of the material matched the pattern for the mineral known as atacamite, which is a geologically crystallized form of Cu2(OH)3Cl. By controlling five parameters in a rather tight operating window it was found possible to make the target compound with good crystallinity and to grow the particles to a size that could be easily washed, and would result in a free-flowing, non-dusty product.

The second initial hurdle was overcome by developing a proprietary process to scavenge all residual heavy metals from the strongly complexing matrix. Analysis confirmed that the result was a remarkably clean solution of ammonium chloride. Both lab and field tests indicated it was suitable as a base stock to formulate fresh alkaline etchant, which could then be shipped to the printed circuit fabricators. The cake containing the removed metals had a chemical analysis virtually identical to copper mine concentrate. It did not display hazardous characteristics and was an excellent candidate for recycling through a smelter for its copper content.

Scale-up of the Process

For initial lab work, the reaction was carried out in beakers on magnetic stirrers. When it became obvious that better control of reagent interactions was needed, a three-liter bench top reactor was constructed. When encouraging results on crystal growth were obtained, the process was moved to a pilot plant with a 1,200 liter reactor.

After demonstrating successful scale-up of the reactor, the R&D pilot plant was converted to run as a miniature production facility. This was done to confirm that the process would be reliable and robust when handling the variability of commercial feedstocks. The retrofit involved storage tanks for feedstock and product solutions and a dryer for the copper product. For ten months, three PWB manufacturers were served by the semi-works facility while the full-scale plant was designed and built on a greenfield site.

On the commercialization front, one of the first actions was to request an informal review opinion from U.S. FDA on the safety of using basic copper chloride as a source in animal feed. A favorable opinion letter was received during the pilot testing phase after eighteen months and three submittals of detailed technical and experimental data. Subsequently, the American Association of Feed Control Officials was petitioned to create a new official ingredient listing for basic copper chloride (AAFCO 57.154). Meanwhile, the pilot plant output was test marketed in the animal feed industry under the trademarked name Micronutrients TBCC®, referring to an informal name for the copper salt - tribasic copper chloride. Two U.S. patents were issued covering the use of basic copper chloride as a nutritional source of copper in food, animal feed, and fertilizer (7,8).

Construction of the full-scale plant was started in October, 1994, and initial production occurred in June, 1995. The reactor is a 16,000 liter vessel. By late 1999, the plant was serving 65 PWB manufacturing facilities by supplying fresh alkaline etchant and accepting spent cupric and ammo for use as feedstocks.

 TBCC Process Diagram
Conceptual Diagram of TBCC Process


Research Studies Published or Presented at Animal Science Meetings

Early in the development project, laboratory samples were used in studies at the University of Florida to confirm efficacy in animal feed applications. Three studies were run in 1992, 1993 and 1994. The first two were chick feeding experiments designed to investigate how TBCC compared to copper sulfate for bioavailability and safety, while the third evaluated the salts for prooxidant activity. The first study on bioavailability was presented by Ammerman (9) while the results of all three were combined in a published paper by Miles, et al (10).

A series of three feeding trials in pigs were conducted in 1994 and 1995 and reported by Cromwell, et al (11). The third was a large trial in a research facility using commercial production conditions and showed that TBCC outperformed copper sulfate on rate of weight gain.

Several research studies have been done in cattle at North Carolina State University. The first two of these have been reported by Spears, et al (12,13). These have shown that TBCC helps to more reliably maintain optimum copper status even when antagonists such as sulfur and molybdenum are present in the diet. This is achieved because the basic copper chloride salt is insoluble at the neutral pH that prevails in the rumen, and thus remains available for subsequent absorption rather than being precipitated as refractory copper thiomolybdate.

Most recently, a series of three studies done in broiler chickens under various levels of disease stress confirmed better bioavailability, rate of weight gain, feed conversion efficiency and vitamin preservation when using TBCC as compared to copper sulfate. These have been reported by Hooge, et al in three different presentations (14,15,16).
  1. Mortvedt , J. J., Cox, F. R., Shuman, L. M., Welch, R. M., Eds., Micronutrients in Agriculture, Second Edition, SSSA, Madison, WI, U.S.A.,1991, 703-705.

  2. Combs, G.F. Jr., "Adequate vs. Optimum", Petfood Industry, Vol. 4, 1998, 31-43.

  3. Mortvedt , J. J., Cox, F. R., Shuman, L. M., Welch, R. M., Eds., Micronutrients in Agriculture, Second Edition, SSSA, Madison, WI, U.S.A.,1991, 612-614.

  4. Internal Market Research, Micronutrients, March, 1994.

  5. O’Keefe, S. F., and Steward, F. A., "Food Stability – a Mineral’s Chemical Form Dictates How Actively It Promotes Oxidation", Petfood Industry, May/June, 1999, 46-50.

  6. Richardson, H. Wayne, Ed., Handbook of Copper Compounds and Applications. Marcel Dekker, Inc., New York, NY, U.S.A., 1997, 71. No. 5,534,043, 9 July 1996.

  7. Ammerman, C. B., Henry, P. R., luo, X. G., and Miles, R. D., "Bioavailability of Copper from Tribasic Cupric Chloride for Nonruminants", Paper presented at the American Society for Animal Science, Southern Section Meeting, New Orleans, LA, U.S.A., 28 January – 1 February, 1995.

  8. Miles, R. D., O’Keefe, S. F., Henry, P. R., Ammerman, C. B., and Luo, X. G., "The Effect of Dietary supplementatio with Copper Sulfate or Tribasic Copper Chloride on Broiler Performance, Relative Bioavailability, and Dietary Prooxidant Activity", Poultry Science, 1998 77:416-425

  9. Cromwell,G. L., Lindemann, M. D., Monegue, H. J., Hall, D. D., and Orr, D. E., Jr., "Tribasic Copper Chloride and Coper Sulfate as Copper Sources for Weanling Pigs", J. Anim. Sci. 1998 76:118-123.

  10. Spears, J. W., Kegley, E. B., Mullis, L. A., and Wise, T. A., "Bioavailability of Copper From Tri-basic Copper Chloride in Cattle", J. Anim. Sci. 1997 75 (Suppl. 1): 265

  11. Engle, T. E., Spears, J. W., Armstrong, T. A., Wright, C. L., and Odle, J., "Effects of Dietary Copper Source and Concentration on Carcass Characteristics and Lipid and Cholesterol Metabolism in Growing and Finishing Steers", J. Anim. Sci. 2000 78:1053-1059.

  12. Hooge, D. M., Steward, F. A., and McNaughton, J. L., "Efficacy of Dietary Tribasic Copper Chloride (TBCC) versus Copper Sulfate Pentahydrate for Improving Productive Performance of Broiler Chickens", Paper presented at the International Poultry Scientific Forum, Atlanta, GA, U.S.A., 17 January, 2000.

  13. Hooge, D. M., Steward, F. A., and McNaughton, J. L., "Bioavailability of Copper from Tribasic Copper Chloride (TBCC) Compared to Copper Sulfate Pentahydrate in Broiler Chicken Diets", Paper presented at the International Poultry Scientific Forum, Atlanta, GA, U.S.A., 17 January, 2000.

  14. Hooge, D. M., Steward, F. A., and McNaughton, J. L., "Improved Stabilities of Vitamins A, D3, E and Riboflavin with Tribasic Copper Chloride (TBCC) Compared to Copper Sulfate Pentahydrate in Crumbled Broiler Starter Feed", Paper presented at the 89th Annual Meeting of the Poultry Science Association, Palais de Congress, Montreal, Quebec, Canada, 19 August, 2000.

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Phone: 317-486-5880
Fax: 317-486-5888

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A Division of Heritage Technologies, LLC

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