Cold-pressed solid agglomerates and method for producing same

Abstract

The present invention relates to a cold pressed solid agglomerate using an organic binder. In this regard, the present invention provides a cold pressed solid agglomerate containing a mixture comprising at least one main compound and at least one organic binder, said at least one organic binder being obtained by chemical reaction of starch in an aqueous medium at room temperature under pH controlled by at least one alkali. Furthermore, the present invention provides a method for producing a cold pressed solid agglomerate comprising the steps of: (i) mixing at least one main compound with at least one organic binder; (ii) cold pressing the mixture to form an agglomerate, said at least one organic binder being obtained by chemical reaction of starch in an aqueous medium at room temperature under pH controlled by at least one alkali.

Description

[Technical field]

[0001] The present invention relates to solid agglomerates, in particular to cold pressed solid agglomerates using an organic binder. [Background technology]

[0002] Cold agglomeration consists in bringing together fine material to obtain larger products through the use of binders. This method allows, for example, to obtain high-quality metal aggregates or coal briquettes by using a fraction made up of small particles that would normally be discarded.

[0003] Coal briquetting is one of the various cold agglomeration methods that are gaining popularity in the industry. This technique, which can be used for both mineral and vegetable coal, typically involves the steps of: i) granulometric balancing of the coal or biomass particles; (ii) mixing with a binder (agglomerant); (iii) mechanical compression; and (iv) drying the briquettes.

[0004] Binders used in the briquetting process may be of mineral or organic origin. These binders play an important role in the formation of the briquette, giving the green briquette and its subsequent drying thermoplastic properties (plasticity, toughness, and compression resistance). Currently, one of the most widely used organic binders in the coal briquetting industry is corn flour or corn starch, heat treated at temperatures between 130 and 150 °C by extrusion or drum dryers.

[0005] Both heat treated corn flour and corn starch require relatively expensive and complex equipment and facilities to produce. Also, the heat denaturation process that the flour and / or corn starch undergo breaks down their molecular chains and greatly reduces their binding properties. This means that the amount of binder in the briquette increases, and if the binder percentage is high enough to cause a reduction in the amount of charcoal or biomass in the briquette, the final product becomes more expensive and its heating value decreases.

[0006] Finally, it should also be noted that the industry is developing and exploring alternatives to improve the performance and properties of physical briquettes from the formation of the physical briquettes (green) to the firing in furnaces and steel reactors. In this regard, it is currently very common to use powder (or liquid) additives in the briquette composition to improve certain briquette properties. In this scenario, prior art binders have limitations because the percentage of moisture (free water) in the agglomerates can be lower than the amount required to fully gelatinize the flour and heat-treated starch in powder form. This condition prevents the development of the adhesive properties of the heat-treated corn flour or starch binder.

[0007] The present invention aims to solve the above problems in a practical and efficient manner. Summary of the Invention [Problem to be solved by the invention]

[0008] The primary objective of the present invention is to provide a cold pressed solid agglomerate and method for its manufacture that uses a binder that is easy to manufacture and does not require the use of equipment, facilities, and heat energy to industrialize the binder.

[0009] A second object of the present invention is to provide a cold pressed solid agglomerate and a method for its production which uses less binder.

[0010] A third object of the present invention is to provide a method for producing the cold pressed solid aggregates and the same which provides operational practicality using a liquid binder which is water miscible and flowable at room temperature, facilitating the incorporation and dissolution of additives into the mixture. [Means for solving the problem]

[0011] In order to achieve the above object, the present invention provides a cold pressed solid agglomerate containing a mixture comprising at least one main compound and at least one organic binder, the at least one organic binder being obtained by chemical reaction of starch in an aqueous medium at room temperature with at least one alkali under controlled pH.

[0012] The present invention further provides a method for producing cold pressed solid agglomerates comprising the steps of: (i) mixing at least one primary compound with at least one organic binder; and (ii) cold pressing the mixture to form an agglomerate, wherein the at least one organic binder is obtained by chemical reaction of starch in an aqueous medium at room temperature under pH controlled by at least one alkali. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Please note in advance that the following description begins with the preferred embodiments of the present invention, however, it is obvious to those skilled in the art that the present invention is not limited to these specific embodiments.

[0014] The present invention provides a cold pressed solid agglomerate and a method for making the same. The cold pressed solid agglomerate of the present invention comprises a mixture containing at least one primary compound and at least one organic binder.

[0015] The primary compound may be, for example, at least one of biomass, charcoal, and mineral coal. Such a compound may be a mixture of various coals or biomass, possibly with different compositions and particle sizes. Alternatively, the primary compound may be at least one metal, giving rise to metal aggregates.

[0016] Preferably, the at least one organic binder is obtained by chemical reaction of starch in an aqueous medium at room temperature and under controlled pH with at least one alkali, more preferably sodium hydroxide.

[0017] The at least one organic binder is a mixture of the following reagents in the following weight proportions: Water: 83~87.5%; Starch: 12-16%; Sodium hydroxide: 0.5-1%, It is preferably obtained using

[0018] The starch used in the reaction of the present invention is preferably normal corn starch, also known as native corn starch. The sodium hydroxide used in the reaction of the present invention is preferably 10% to 50% sodium hydroxide (aqueous sodium hydroxide solution).

[0019] Preferably, the at least one organic binder produced in the chemical reaction is in a form that allows the additive to be diluted in a practical manner.

[0020] The process for producing cold pressed solid agglomerates according to the present invention comprises the steps of: (i) mixing at least one primary compound with at least one organic binder; and (ii) cold pressing said mixture to form the agglomerates, for which the at least one organic binder is obtained by chemical reaction of starch in an aqueous medium at room temperature under pH controlled by at least one alkali.

[0021] Optionally, the method of the present invention includes the step of adding an additive to the mixture prior to the step of cold pressing the mixture.

[0022] Optionally, the method of the present invention includes the step of drying the solid agglomerates after the step of cold pressing the mixture.

[0023] Tests have shown that the cold pressed solid agglomerates according to the invention obtained by the above process have significantly better physical properties when compared to prior art agglomerates using extruded or drum dried heat modified corn flour and / or starch as binder. Table 1 below shows the results of various tests on the agglomerates of the invention, specifically raw coal briquettes, and the prior art agglomerates.

[0024] [Table 1]

[0025] As can be seen, the solid agglomerates according to the invention performed significantly better than prior art agglomerates using wheat flour and / or heat modified starch as binder. The results shown by the raw briquettes showed that the greater degree of gelatinization promoted by the binder chemical reaction leads to greater adhesion between the agglomerate particles, resulting in superior performance in terms of toughness (drop test) and greater compression resistance.

[0026] In addition to the above mentioned improvement in properties, the method of obtaining the organic binder used in the aggregates of the invention is not thermomechanical, so there is no destruction of the starch molecules and no loss of their binding properties. As a result, up to 70% of the binder used in the manufacture of the aggregates of the invention is saved when compared to the aggregates of the prior art. This also contributes to a significant improvement in the purity of the aggregates by increasing the fraction of the main compound (e.g. coal, etc.) in the product.

[0027] Thus, as explained above, the present invention provides a cold pressed solid agglomerate and method for its manufacture using an easy to manufacture binder, eliminating the need for an extruder and the use of heat energy to process starch. Furthermore, because the present invention uses a liquid binder, additives can be easily and practically dissolved in the mixture. Finally, the technology of the present invention uses significantly less binder when compared to prior art agglomerates, increasing the purity of the solid agglomerate.

[0028] It is emphasized that the invention is not limited to the embodiments described above, since many variations are possible which affect the scope of protection of the present application.

Claims

1. 1. A cold-pressed solid agglomerate comprising a mixture comprising at least one primary compound and at least one organic binder, 1. A cold-pressed solid agglomerate, characterized in that said at least one organic binder is obtained by chemical reaction of starch in an aqueous medium at room temperature under pH controlled by means of sodium hydroxide.

2. 10. The aggregate of claim 1, wherein the primary compound is composed of at least one metal or at least one of biomass, charcoal, and mineral charcoal.

3. The at least one organic binder comprises the following proportions by weight of reagents: Water: 83-87.5%; Starch: 12-16%; Sodium hydroxide: 0.5-1% 3. The aggregate according to claim 1 or 2, characterized in that it is obtained using

4. 3. The aggregate according to claim 1 or 2, characterized in that the starch is ordinary corn starch.

5. 3. The aggregate according to claim 1 or 2, characterized in that the at least one organic binder is miscible in water and fluid at room temperature.

6. 3. The aggregate according to claim 1 or 2, further comprising at least one additive.

7. mixing at least one primary compound with at least one organic binder; cold pressing the mixture to form an agglomerate; 1. A method for producing a cold-pressed solid agglomerate, comprising:

1. A method according to claim 1, wherein said at least one organic binder is obtained by chemical reaction of starch in an aqueous medium at room temperature under pH controlled by means of sodium hydroxide.

8. In the chemical reaction step, the following mass proportions of reagents are used: Water: 83-87.5%; Starch: 12-16%; Sodium hydroxide: 0.5-1% 8. The method according to claim 7, characterized in that:

9. 9. The method according to claim 7 or 8, characterized in that it comprises the step of adding an additive to the mixture before the step of cold-pressing the mixture.

10. 9. The method of claim 7 or 8, further comprising the step of drying the solid agglomerates after the step of cold pressing the mixture.