Magnesium chloride bonded phosphate rock powder agglomeration (2)

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Source: internal company

Magnesium chloride bonded phosphate rock powder agglomeration (2)

Experimental part
1. Influence of the amount of bitter soil powder on the strength of agglomerate
100 grams of mineral powder and 1 gram of magnesium chloride are fixed, and the dosage of bitter soil powder (1, 2, 3, 4, 5, 7 grams) is changed. 4x4mm squares were made respectively, and the compressive strength test was carried out 20 days later.

From the test results, it is found that the compressive strength of the agglomerate increases gradually when the addition amount of bitter soil powder increases. When the addition amount was 2 g, sufficient strength (96.95 kg/cm2) was already present. When the bitter soil powder continues to increase, the strength still increases, but the increasing trend is not as large as that at 1-2g. Considering the industrial production and binder cost, we think that the best addition amount of bitter soil powder is 2-4g.

2. The effect of magnesium chloride addition on the strength of agglomerate
Test conditions:
Fix 100g of phosphate rock powder and 5g of bitter soil powder, change the dosage of magnesium chloride to make square ore, and carry out compressive strength test 20 days later. From the test results, it is known that the compressive strength of the agglomerate increases with the increase of the addition of magnesium chloride. Especially when 0.5 g is increased to 1 g. If magnesium chloride continues to be increased, although the strength of the agglomerate can be increased, the range is not as large as that at 0.5-1g. At the same time, the price of magnesium chloride is higher than that of bitter soil powder, so we think that when the addition amount of bitter soil powder is 2-4g, the addition amount of magnesium chloride is 1-1.5 g.

3. Influence of curing time on strength of agglomerate
Test conditions:
Phosphate rock 100g, magnesium chloride 1g, bitter soil powder 3, 5, 10 g three kinds of pellets, respectively, for 10 days, 15 days, 25 days of curing three kinds of samples drop test. A layer of 20 mm thick steel plate is laid on the cement floor, and the pellets are freely dropped from 2 meters high, repeated three times, and the strength of the pellets is measured by weighing method by measuring the percentage of lumps larger than 10 mm each time in the total amount of the pellets.

The results show that with the increase of curing time, the strength of the agglomerate also increases obviously. Starting from 15 days, the block content of 3-5g bitter soil powder is relatively high, and 10g is the best. If there is 15-20 days of maintenance, the strength of the agglomerate can already meet the requirements of blast furnace entry. In addition, we also put the newly formed wet lump ore in an oven at a constant temperature of 120 ℃ and then put it into a muffle furnace at a constant temperature of 500 ℃ for 12 hours, but the strength was very poor after cooling.

Water addition
The amount of water added should be different considering the water content, particle size and amount of bitter soil powder of phosphate rock. Generally, it is 8%-10% of the amount of mineral powder, so it is advisable to adjust the humidity until the ball is kneaded by hand. We use 15% magnesium chloride aqueous solution to mix it quantitatively and supplement it with water when it is not enough.

4. Thermal stability test
The samples are not cracked, comminuted or deformed, which shows that the thermal stability of this kind of phosphate rock pulverized ore is very good and meets the requirements of blast furnace on the thermal stability of furnace burden, when the pulverized ore with different proportions is put into the muffle furnace, gradually rising from low temperature to 900 ℃, and kept for another two hours, the samples are not cracked, comminuted or deformed. The results show that the thermal stability of this kind of phosphate rock pulverized ore is very good.