JPH06509390A - ore granulation - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [　The present invention involves making a homogeneous mixture of particle ore and particle binder in the presence of moisture, and A green pellet is created by agitation (e.g. rolling or tampling) of the mixture. and burning the unburned pellet to produce an ore pellet. This relates to a granulation method.

Bentonite is widely used as a particle binder, but synthetic or natural polyesters Many proposals have been made to use mar.

One class of natural polymers that have been used are various soluble starches. Another one One class are soluble cellulose derivatives, typically esters (especially carboxymers). cellulose) or ethers (especially hydroxyethylcellulose) . Another type of MtR is soluble gums such as xanthan gum and guar gum. Conclusion It is proposed to use a mixture of synthetic clay (bentonite) with polymers .

For example, Clum et al. Gineers) 1978 (NY) 30 (1), page 53 , guar gum, hydroxyethyl cellulose, polyoxyethylene oxide and Results obtained using a binder containing Bentonite and Bentonite are shown.

A number of proposals have also been made for the use of various soluble particle synthetic polymers. this grain Child binders are water-soluble, ionic, ethylenically unsaturated monomers or monomers. formed by polymerizing a mixture to form water-soluble polymer particles. most of which consist of synthetic polymer particles up to 300 μm in size. . For example, the monomer mixture contains a crosslinker to avoid the risk of insolubilization associated with crosslinking. For example, in EP-A-225171 we describe Use of water-soluble synthetic polymers, which are anionic polymers, as particle binders. EPO 288150 describes the use of cationic polymers. is listed.

Using a soluble anionic synthetic polymer as a granulation binder Although there are some advantages over using It has the disadvantage that it is difficult to impart sufficient dry strength. If to improve dry strength Even if the application rate is increased, there is still another drawback, namely, pellet glue in the drum. Disadvantages such as deposition and agglomeration and instability in the granulation process may occur.

Similarly, the use of only natural polymers can improve green strength, dry strength and drop count. Since it may not be possible to obtain the combination of optimal conditions for It has not been proven that.

In the ore granulation method of the present invention, particle ore is mixed with a particle binder in the presence of moisture. and granulate the mixture. The particle binder is an ionic synthetic water-soluble polymer. Soluble gum, soluble starch, and soluble cellulose derivative per 1 part reamer A mixture of 2 to 30 parts of soluble natural polymers selected from: Specification Parts used in this book are parts by weight.

Natural polymers include, for example, cellulose ethers such as hydroxyethylcellulose. cellulose esters such as carboxymethyl cellulose, soluble starch, and An example of this is xanthan gum, but soluble guar gum is preferable. guar gum are treated by known methods to increase solubility. For example, guar gum is treated with phosphoric acid. It may be something.

The amount of synthetic polymer is generally at least 0.005% by weight, usually less than 0° 0.1% by weight (relative to the weight of the total mixture), but generally more than 0.1% by weight (relative to the weight of the total mixture). Often less than that, for example less than 0.06% by weight. 0.01 to 0.04% by weight is often suitable.

The total amount of water-soluble synthetic and water-soluble natural polymers used in the present invention will typically be at least 0.03%, often at least 0.05%. Generally more than 0.3% This is undesirable and is usually 0. Less than 2%. 0.05 to 0. 1 more 0.15% is appropriate in case of large amount.

To obtain beneficial binding results using remers, generally the area should be 4% or more. The proportion is at least 3 parts, often at least 5 or 6 parts. Usually from part 15 in proportions of 0.2 to 2 parts, often around 0.7 to 1.5 parts. Preferred binders include 1 part by weight of a soluble synthetic polymer, 0. 7 to 1.3 parts by weight of sodium carbonate and 2 to 12 parts by weight of guar gum.

The components of the binder may be mixed or separated prior to use, but preferably substantially simultaneously. or other salts) is generally between 0.03 and 0.03. 3% range, often around - contains 10 to 40% acrylamide and often 15 to 30% acrylamide. A copolymer of sodium sulfate is usually preferred.

However, larger amounts of sodium acrylate, e.g. 50 to 80% , a usage of approximately 70% is generally desired. Intrinsic viscosity is 2 or 3 to 16 dl range of 5 to 12 dl/g, but some In some cases it can be even higher, for example up to 25 dl/g.

Soluble synthetic polymers, when they are normally polymerized in the absence of crosslinking agents, It is desirable that the chain be completely linear. However, synthetic polymers are water-soluble and It may also be advantageous to have partially crosslinked polymers. The amount of crosslinking agent is , insufficient to confer superior water insolubility to the polymer particles, but a useful benefit, In particular, it is sufficient to give an increase in the dry strength of ore pellets, and the particles are still water soluble. As polymer particles, they have excellent You should make choices that will allow you to behave accordingly. The amount of crosslinking agent is determined by the intrinsic viscosity (IV) Generally 5 to 50 ppm when 2 to 7 dl/g, preferably 7 to 2 0 ppm, 2 to 30 ppm when IV is 7 to 16 dl/g, preferably 5 to 1 sppm. These IV values were measured on polymers without crosslinkers. The amount of crosslinker was calculated as the amount of methylene bisacrylamide. others If one seeks to obtain similar rheological and solubility characteristics using crosslinking agents of Different, generally higher amounts will be required. Generally, the amount of crosslinking agent is Calculated as the amount of methylenebisacrylamide, it is 18 ppm or less.

Herein, IV values are the conventional single point in dI/g at 20°C. Determined by IV measurement.

Some or all of the components of the particle binder used in this invention may be Although it may be given as a powdered oil, it is generally given as a powder particulate component. is preferred. The particles may be aggregates, for example as described in EPO 326382. Good too. The size of the binder particles is usually less than 300 μm, generally less than 200 μm. , preferably less than 150 μm, but generally greater than 20 μm.

The grain ore is preferably iron ore, but other ores that can be granulated, such as zinc It may be an ore. The materials and manufacturing conditions are such that the binder contains a specified amount of guar. Generally, those described in EP 225171 except that gum must be included. Applicable. Bentonite can be used as part of the binder.

In Examples 1 and 2 below, the granulation method is as in the example of EP225171. guar gum and the anion formed as in EP225171. The experiments were carried out using various combinations of polymers. The results are shown below.

Example 1 Product A - 50150 mixture of 20% anionic polyacrylamide and sodium carbonate Compound Product B - Guar Gum Product C - 2/7 Active Polymer Mixture Unbaked Dry Drops of A and B % Strength/Kg Strength/Kg Number Moisture 0.09%C1,002,8029,310,30,10%B 1.31 2. 26 37.0 9.7 Example 2 Product D - 115 Active Polymer Mixture Unbaked Dry Drops of A and B % Strength/Kg Strength/Kg Number Moisture 0, Engineering 2%D 1.18 8.15 21.3 10.5112%B 1.30 6.08 45.0 10.0 Anionic polyacrylamide sodium carbonate The combination of mixtures with and guar gum gave acceptable unbaked properties. However, the dry strength was increased compared to when guar gum alone was used.

In the two examples mentioned above, the dry strength is the mixture of guar gum and synthetic polymer. As a result of this, they increased by 24.0% and 34.0%, respectively. Therefore, even if dry Although dry strength tends to be a problem for binders based on synthetic polymers, The addition of polymers to guar gum allows the same amount of natural polymer to be added to P in the absence of synthetic polymers. CT/GB 92101432 Continuation of front page (81) Designated countries EP (AT, BE, CH, DE.

DK, ES, FR, GB, GR, IE, IT, LU, MC, NL, SE), 0A (BF, BJ, CF, CG, CI, CM, GA, GN, ML, MR, SN, TD, TG), AT, AU, BB, BG, BR, CA, CH, C5゜DE, DK, ES, FI, GB, HU, JP, KP, KR, LK, LU, MG, MN, MW, NL, NO, PL, RO, RU, S D, SE, US (72) Inventor Allen, Anthony Peter - United Kingdom West Yorkshire, Beedie, 18.3 Easet, Shipley, Sal. 4 George Street, Tyre

Claims (7)

[Claims] 1. Mixing particulate ore with particulate polymer binder in the presence of moisture and granulating the mixture The particle polymer binder is an ionic synthetic water-soluble polymer. selected from soluble gum, soluble starch and soluble cellulose derivative for 1 part an ore comprising a mixture of 2 to 30 parts of a soluble natural polymer; granulation method. 2. The synthetic polymer is an anionic polymer and the natural polymer is guar gum. The method according to claim 1, characterized in that: 3. The amount of synthetic polymer is in the range of 0.005 to 0.1% by weight based on the total amount of the mixture. and the amount of natural polymer is from 0.05 to 0.2% by weight. 3. The method according to claim 1 or 2. 4. The amount of natural polymer is 3 to 10 parts by weight per 1 part by weight of synthetic polymer. 4. A method according to any one of claims 1 to 3, characterized in that: 5. The synthetic polymer contains 10 to 90% acrylamide and 90 to 10% acrylamide. Formed from a mixture of sodium lylate and having an intrinsic viscosity of 2 to 16 dl/g A method according to any one of claims 1 to 4, characterized in that: 6. The synthetic polymer contains 60 to 90% by weight acrylamide and 40 to 10% by weight % sodium acrylate and has an intrinsic viscosity of 5 to 9 dl/g. 6. The method according to claim 1, further comprising: 7. A claim characterized in that the ore is mainly iron ore in the form of particles less than 250 μm. 6. The method according to any one of 1 to 6.