Concentrated sugar additive as anti-dusting agent

Abstract

The present invention generally concerns a concentrated sugar additive comprising (a) raffinate derived from citric acid recovery industry and (b) sugar-containing solution useful for controlling dust emission from particulate materials during manufacturing, handling, storage or transportation. Such particulate materials comprise fertilizers, minerals, coal, etc.

Claims

1. An anti-dusting additive comprising a mixture of a citric acid containing raffinate and an added sugar-containing solution; wherein the raffinate contains about 50% dry matter by weight and less than 5% citric acid by weight of dry matter and the anti-dusting additive having: (a) a % Brix from about 60 to about 80; and (b) a minimum viscosity of about 100 cP (at 25 C.).

2. The anti-dusting additive according to claim 1 comprising from about 10 to about 90% raffinate.

3. The anti-dusting additive according to claim 2 comprising about 40% raffinate.

4. The anti-dusting additive according to claim 1; wherein the added sugar-containing solution comprises a monosaccharide, disaccharide, oligosaccharide, polysaccharide, or mixture thereof.

5. The anti-dusting additive according to claim 4; wherein the sugar-containing solution comprises glucose syrup.

6. The anti-dusting additive according to claim 5 comprising from about 10 to about 90% sugar-containing solution.

7. The anti-dusting additive according to claim 6 comprising about 60% sugar-containing solution.

8. A process for manufacturing an anti-dusting additive of claim 1 comprising the steps of: (a) evaporation of a citric acid containing raffinate to about 50% dry solids by weight; (b) mixing a sugar with the product of step (a) until complete homogenization; (c) controlling the viscosity of the product of step (b) by addition of a glucose syrup until a viscosity of between 100 to 100,000 cP (at 25 C.) is acheived.

9. A method of reducing the dust in the manufacture, transportation, or application of fertilizers comprising spraying a dust reducing amount of the product of claim 1 onto the fertilizer.

10. A fertilizer comprising an anti-dusting additive according to claim 1.

Description

DESCRIPTION OF THE INVENTION

(1) In order to overcome the inconveniences related to the dust emission from fertilizers and mining industry, specially related to pollution and toxicological effects, a specific concentrated sugar additive was developed to be used as anti-dusting agent for fertilizers and mining industry in general, which controls powder emission in several stages, for instance manufacturing, handling, storage, transportation, impact, wind erosion, stacking, crushing, milling, breaking, or reclaiming operations.

(2) The additive according to the present invention comprises (a) raffinate and (b) sugar-containing solution.

(3) According to the present invention the raffinate (a) is an aqueous solution effluent (for instance syrup or liquor) from fermentation processes (residuary or not). Raffinate (a) is an aqueous solution comprising at least citric acid, inorganic matter (such as minerals), proteic matter and sugar matter.

(4) Typically, sugar matter includes carbohydrate selected from fructose, dextrose, maltose and/or polyol selected from arabitol, erythritol, or mixtures thereof. The inorganic matter is measured by analyzing ashes and typically includes nitrogen, phosphorus, potassium, calcium, magnesium, sulphur, iron, manganese, copper, zinc, boron, sodium or mixtures thereof.

(5) In a particular embodiment, raffinate (a) may be a by-product derived from the citric acid recovery process, for instance as disclosed in the patent U.S. Pat. No. 4,994,609, assigned to Cargill Inc. (1991), incorporated herein as reference. The raffinate (a) ingredients ratio depends on the performance of the recovery industry. In this case, a by-product without commercial application is used as raw material to the manufacture of a commercial product, also avoiding cost with waste treatment.

(6) The sugar-containing solution (b) may be obtained from several sources, for instance corn, sugar cane, cassava, potato, wheat, rice, etc. In a particular embodiment such a solution may be syrup, i.e. a viscous liquid with a sugar content. Such a component also includes enzymatic or acid conversion syrup, independently from the conversion grade.

(7) Sugar, according to the present invention, is selected from carbohydrates or saccharides in general, including monosaccharides, disaccharides, oligosaccharides, polysaccharides; or mixture thereof. For instance, the solution (b) comprises monosaccharide such as glucose (dextrose), fructose (levulose), galactose, xylose or ribose; disaccharides such as sucrose, maltose or lactose; oligosaccharides such as raffinose or stachyose; polysaccharides such as or starch, amylose, amylopectin, cellulose, chitin; hydrolysates (for instance inverted sugar), derivatives or mixtures thereof.

(8) According to the present invention the sugar-containing solution (b) may be a viscous concentrated solution of sugar, in water or other liquids (for instance alcohols). Such a solution may also include other ingredients such as coloring agents, flavors or thickening agents.

(9) In a particular embodiment component (b) contains about 40% equivalent dextrose in relation to about 80% total solids. For instance, such an ingredient is commercialized as Glucogill 40/82 by the Cargill group in Brazil.

(10) The concentrated sugar additive useful as anti-dust agent comprises:

(11) (a) from about 10 to about 90%, preferably about 40% raffinate from a citric acid recovery process, and

(12) (b) from about 90 to about 10%, preferably about 60% glucose syrup.

(13) As a second aspect, the present invention also concerns a process for manufacturing an anti-dusting agent comprising the following steps of:

(14) (i) evaporation of raffinate component (a) up to about 50-65% solids;

(15) (ii) mixing sugar-containing solution (b) until complete homogenization;

(16) (iii) controlling the viscosity by addition of sugar-containing solution (b) if necessary, considering a minimum of about 100 and a maximum of about 100,000 cP (at 25 C.), particularly about 500 to about 10,000, more particularly about 1,600 to about 2,500.

(17) The resulting anti-dusting additive according to the present invention presents the following characteristics:

(18) (a) % Brix (sugar parameter) from about 60 to about 80, particularly about 70-75.

(19) (b) Viscosity: a minimum of about 100 and a maximum of about 100,000 cP (at 25 C.), particularly about 500 to about 10,000, more particularly about 1,600 to about 2,500.

(20) The % Brix is analyzed by a refractometer. The viscosity is measured by cooling the sample at 25 C. and 20 rpm in a Brookfield viscometer DV I.

(21) Due to the characteristics of the additive according to the present invention, especially with respect to controlled concentrations of sugar, as well as physical characteristics (viscosity), it is possible to obtain an improved ingredient able to act as anti-dusting for a broad range of inorganic fertilizers or mining products.

(22) It was found that the application as anti-dusting is not possible with the use of sugars alone (for instance glucose), due to its high viscosity. Contrary to what one would expect, the raffinate (a) is able to control the sugar-containing solution viscosity allowing the anti-dusting application for fertilizers and mining industry, i.e. due the formation of a film with improved anti-dusting properties. Moreover, there is a use of a waste derived from citric acid industry, providing a low-cost and environment friendly anti-dusting product, which also helps the fertilizer function by distributing micronutrients in small and suitable amounts.

(23) The concentrated sugar additive according to the present invention may also comprise other ingredients well known in the art, such as surfactants, biocides, pH adjusters, thickeners, etc.

(24) The inorganic fertilizers treated in accordance with the present invention include, without any limitation, for instance the compounds disclosed in the handbook The Fertilizer Encyclopedia (2009) or Merck Index: 13th edition (2006), also incorporated herein by reference. Exemplary compounds include phosphates, such as ammonium phosphate, including monoammonium phosphate (MAP) and diammonium phosphate (DAP), and single and triple superphosphates, nitrates, such as ammonium nitrate and potassium nitrate, sulfates, such as ammonium sulfate, and potassium magnesium sulfate, chlorides such as potassium chloride, limestone, dolomite and mixtures thereof.

(25) Mining products include, without any limitation, for instance coal, petroleum coke, minerals or metals.

(26) The present invention also concerns to the use of the additive as described above as anti-dusting agent for mining industry, particularly to avoid powder from impact or wind erosion, or a method for reducing dust emission. This method is particularly useful to avoid dust from impact or wind erosion or during stacking, crushing, milling, breaking, or reclaiming operations.

(27) In addition, the present invention also concerns to the use of the additive as described above as anti-dusting agent for fertilizers or a method for reducing dust emission from fertilizers during manufacturing, transportation or application that comprises applying a dust reducing amount of an additive as described above. In a preferred embodiment of the invention, the dust reducing amount ranges from about 0.01 to 0.5% by weight.

(28) This method is particularly useful for producing a particulate fertilizer having reduced dust emission content compared to particulate fertilizers with additives such as petroleum-based coating agents, oils, by-products such as molasses or vinasses with uncontrolled sugar contend.

(29) Particulate fertilizers are manufactured according to processes well known to those skilled in the art, such as crystallization techniques or recovered naturally in a granular form can be treated to reduce fugitive dust emission in accordance with the method of the present invention.

(30) The following examples are provided for illustration and are not intended as a limitation to the scope of the present invention, other than what is described in the attached claims.

EXAMPLES

Obtaining of Raffinate

(31) A raffinate sample was obtained from the citric acid recovery process disclosed in the patent U.S. Pat. No. 4,994,609, assigned to Cargill Inc. (1991).

(32) Such an ingredient was evaluated in order to identify organic and mineral contents.

(33) One of the tests was carried out to verify the mineral ingredients contained in the raffinate (a).

(34) Therefore, ashes without organic elements (i.e. water, citric acid, raw protein and sugar not converted) were evaluated and the following composition was identified:

(35) TABLE-US-00001 TABLE 1 Raffinate characteristics: inorganic elements (<1.0%) Ingredient Amount Nitrogen 0.58% Phosphorus 0.12% Potassium 35.0 ppm Calcium 148.0 ppm Magnesium 25.0 ppm Sulphur 0.25 ppm iron 1.0 ppm manganese 3.0 ppm copper 3.0 ppm zinc 10.0 ppm boron 110.0 ppm sodium 900.0 ppm cobalt molybdenum aluminum chlorine nickel organic carbon organic 19.50% matter pH 2.2 density 1.25 g/mL C/N ratio 19/1 electric 340.0 S/cm condition

(36) Organic elements detected in the sample include:

(37) TABLE-US-00002 TABLE 2 Raffinate characteristics: organic elements Ingredient Amount Citric acid 5% Fructose 1% Dextrose 2% Maltose 4% Arabitol 0.6% Erythritol 2.2%

(38) The analyzed sample also contains solids (15%) and trace ingredients (<100ppm). C/N ratio=19 and pH=3.

Preparation of the Anti-Dusting Additive

(39) A sample of the anti-dusting additive was prepared by:

(40) (a) evaporation of a raffinate stream according to a process disclosed in the patent U.S. Pat. No. 4,994,609 up to 50% solids;

(41) (b) mixing 6 kg of the raffinate obtained in the step (a) with 4 kg of a glucose syrup, commercialized as Glucogill 40/82, until complete homogenization.

(42) The viscosity and sugar content of the resulting mixture was then analyzed:

(43) (a) % Brix (sugar parameter) from about 60 to about 80, particularly about 70.

(44) (b) Viscosity: about 1,900 cP (250 C.).

(45) The information contained in the foregoing, as well as in the examples, allows a person skilled in the art to perform alternative embodiments not expressly described, but which perform the functions taught herein with the results revealed herein. Such equivalent embodiments are encompassed by the scope of the invention and are therefore covered by the claims presented further on.