Phosphate refractory mud is mainly used for the masonry of phosphate bonded high alumina brick, phosphate wear-resistant brick, kyanite and other bricks. The solvent used for phosphate refractory mud is industrial phosphoric acid with a concentration of 85%. Before use, it is diluted into 42.5% dilute phosphoric acid with 1:1 warm water, and then added into the phosphate refractory mud with a volume of 30% - 40% to make the required consistency.

The preparation of phosphate refractory mud should be 8-24 hours in advance. Pour the powder into the acid resistant container (water tank or acid resistant apparatus), add dilute acid, assign special person to take charge of it, mix continuously, make phosphoric acid react fully with refractory mud (at this time, there will be a lot of bubbles escaping, and there will be a pungent smell), then remove the impurities, make it even without block, and then it will become dilute glue. If the temperature is too low and the mixing is uneven, there will be a very thick sediment layer in the cylinder, causing waste. When the ambient temperature is lower than 20 ℃, it is better to heat the surrounding to make the mud temperature reach about 40 ℃, or use 65-90 ℃ hot water when preparing refractory mud. When using high strength fireclay or adding binder in the fireclay, it can be used as soon as it is stirred.

It is suggested that 85% concentrated phosphoric acid should not be used as the solvent in the preparation of refractory mud. Otherwise, it will not only cause waste, but also cause improper paste. When it's thick, it's like skin glue, which can't be scraped. When it's thin, it's like soup water, which can't be scraped by the tile cutter, which can't be plastered to a certain thickness. Some factories have to use a spoon to pave the mortar later, resulting in small joints, insufficient viscosity, poor adhesion and easy to use Draw lots in the process of building refractory bricks

Project indicators		GP-80	GP70	LP-70	LP-55	NP-45
AL2O3 ,%		≥ 80	≥ 70	≥ 70	≥ 55	≥ 45
Fire resistance≥		≥ 1850	≥ 1830	≥ 1790	≥ 1790	≥ 1750
Flexural bond strength ,MPa	110 ℃ × 24h After drying	≥ 2.0	≥ 2.0	≥ 2.0	≥ 2.0	≥ 2.0
	After burning	1500 ℃ × 3h ≥ 6.0	1450 ℃ × 3h ≥ 5.9	1400 ℃ × 3h ≥ 6.0	1400 ℃ × 3h ≥ 5.9	1200 ℃ × 3h ≥ 6.0
0.2MPa load softening temperature (t2.0), ℃,		≥ 1600	≥ 1550	≥ 1320	≥ 1300	≥ 1200
Linear rate of change，%		1500 ℃ × 3h 0～+1.0	/
Bond time, min		1～2
granularity %	+ 0.5mm ,	≤ 1
	-0.074mm ,	≥ 50