Autoclaved aerated concrete is a kind of wall material with many advantages, such as heat preservation, fire prevention, sound insulation, moisture-proof, environmental protection，recycled using etc. The AAC products with porous structure are lighter, and easier to cut, drill and construct which saves the labour cost.
We are specialized in providing services for the whole plant solution of autoclaved aerated concrete, including raw material testing, plant planning, customized equipment design, equipment manufacturing, pre delivery inspection, supervision of project site installation and personnel training.
China is the world's largest consumer of AAC products，now KEDA SUREMAKER is the preferred partner of high-end customers in China. Over the past 20 years, we have served more than 800 customers and held many national industry conferences. Our R & D team has owned 160 patents，the customized design solution has always been our core advantage.
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THE ADVANTAGES OF AAC:
Low density : Can be 325kg /m3
Good thermal insulating properties
Cost few time to build, saving time
Easy to operate , saving labor cost
Good performance of preventing fire
Good sound-insulation properties
Durable , anti-seismic , recyclable
| Processes | Parameter |
| Mixing period | 5-6 minutes |
| Pouring slurry temperature | 40-45 C |
| Cake curing time | 2.5-3.0h |
| Cake curing temperature | 45~55 C |
| Cake strength after curing | 0.15~0.18MPa |
| Autoclaved curing system Before-after autoclave | 0.5h |
| Vacuumize | 0.5h(0~-0.06MPa) |
| Listing pressure | 1.5h(-0.06~1.3MPa) |
| Constant pressure | 8h(1.3MPa) |
| Releasing pressure | 1.5h(1.3~0MPa) |
| total | 12h |
RAW MATERIALS
Cement
Producing AAC block adopts lime-cement mixing calcium system, can use standard 425# cement, and is according to technical requirements GB 175 General Silicate Cement. Before entering factory with manufacture quality certification, The cement should be used in sequence. Cement technical requirements as blow:
(1) Free CaO content should be not more than 1.5%, CaO content is 60%.
(2) NaCl & KCl content should be not more than1%~1.5%.
(3) Specific surface area 2500~3500cm3/g.
(4) Volume stability is qualified.
(5) Setting time initial setting 1~3h final setting 3~6h.
Sand
It should be according to the standard JC/T 662 Sand for Silicate Building Products to select. Generally, the higher quartz content in the sand, the better AAC block quality.
| Name Grade | SiO2% | K2O+Na2O% | Organic matter | Mica% | SO3% | Mud% | Moisture content% |
| High-class | ≥85 | ≤1 | Qualified | ≤0.5 | 1 | 3 | 8 |
| Firs-class | ≥75 | ≤3 | 5 | ||||
| Qualified product | ≥65 | ≤5 | ≤1 | 2 | 8 |
| Name Grade | Content,% | ||
| High-class | First-class | Qualified product | |
| 2.5～5.0(round hole) | 0 | 0 | |
| 1.25～2.5(square hole) | 10 | 10 | |
| 0.16～0.25(square hole) | 60 | 45 | |
| ＜0.16(square hole) | 30 | 45 | |
Lime
Lime is also one of the main raw material. Its function is coordinating with cement to provide effective calcium oxide, than makes it working with SiO2, Al2O3 from silica material under hydrothermal condition to generate hydrated calcium silicate. So it should be according to JC/T621 Quick Lime for Silicate Building Product standard. Effective calcium oxide content should be more than 65%, the best is more than 80%.
Aluminum paste(powder)
Aluminum paste is according to JC/T 407 Aluminum Paste for AAC standard. Aluminum powder should be according to the current national standard, the requirements of Aluminum Powder Part 2: Ball Mill Aluminum Powder GB/T 2085. 2.
Gypsum
Gypsum is a modifier during gas processing in the AAC. The regulating effect of gypsum mainly reflects in deferring the speed of quick lime digesting & slurry thickening. Gypsum should be according to the current national standard, the requirements of Natural Gypsum GB/T 5483. The main chemical compositions of gypsum are CaSO4,CaSO4·2H2O>70%.
Water
According to the standard, water ratio is advisable to 0.60.
| Content | pH | Cl- (mg/L) | SO42-(mg/L) | Na+ +K+(mg/L) | K+ (mg/L) |
| Operating range | 6~9 | ＜600 | ＜1000 | ＜450 | ＜100 |
AAC PLANT PARAMETERS
| No. | Index content | unit | Index value |
| I | Name | AAC block | |
| Production scale(annual capacity) | | 80,000 ~150,000m3; | |
| Specification(cake: 4.2x1.2x0.6) | m | China national standard(GB) | |
| II | Working system(three-shift continuous weekly production) | 300 days / year 22.5 hours / day 7.5 hours / shift | |
| III | Main raw material consumption | ||
| 1. sand | Ton / year | 63,000 | |
| 2.lime | Ton / year | 15,300 | |
| 3. gypsum | Ton / year | 2,700 | |
| 4.cement | Ton / year | 9,000 | |
| IV | Total capacity (ball mill power) | KW | 950(375) |
| V | Annual power consumption | 10,000ＫＷ.h | 215.11 |
| VI | Annual water consumption | Ton | 81000 |
| VII | Annual gas consumption | Ton | 27000 |
| VIII | Single-shift operators(including forklift and boiler gas distribution) | people | 16 |
| IX | Total plant construction area | hectare | 3 |
| Construction area | m2 | 7,000 | |
| Storage covering | m2 | 6,000 |
| No. | Index content | Unit | Index value |
| I | Name | | AAC Block |
| Scale (Annual capacity | | 200,000m3; | |
| Specification ( Cake:4.8x1.2x0.6) | m | China national standards(GB) | |
| II | Working system (three-shift continuous weekly production) | | 300 days/year |
| 22.5 hours/day | |||
| 7.5 hours/shift | |||
| III | Main raw material consumption | | |
| 1.Sand | Ton/Year | 84,000 | |
| 2. Lime | Ton/Year | 20,400 | |
| 3. Gypsum | Ton/Year | 3,600 | |
| 4. Cement | Ton/Year | 12,000 | |
| IV | Total capacity (Ball mill power) | KW | 1,200（510） |
| V | Annual Power Consumption | 0,000KW.h | 271.72 |
| VI | Annual water consumption | T | 108,000 |
| VII | Annual gas consumption | T | 36,000 |
| VIII | Single-shift operators(including forklift and boiler gas distribution) | People | 16 |
| IX | Total plant construction area | Hectare | 3.5 |
| Construction area | m2 | 7,000 | |
| Storage covering area | m2 | 8,000 |
| No. | Index content | unit | Index value |
| I | Name | | AAC block |
| Production scale(annual capacity) | | 300,000m3; | |
| Specification(cake: 6.0x1.2x0.6) | m | China national standard(GB) | |
| II | Working system(three-shift continuous weekly production) | | 300 days / year 22.5 hours / day 7.5 hours / shift |
| III | Main raw material consumption | | |
| 1. sand | Ton / year | 126000 | |
| 2.lime | Ton / year | 30600 | |
| 3. gypsum | Ton / year | 5400 | |
| 4.cement | Ton / year | 18000 | |
| IV | Total capacity (ball mill power) | KW | 1600（815） |
| V | Annual power consumption | 10,000ＫＷ.h | 362.3 |
| VI | Annual water consumption | Ton | 162000 |
| VII | Annual gas consumption | Ton | 54000 |
| VIII | Single-shift operators(including forklift and boiler gas distribution) | people | 16 |
| IX | Total plant construction area | hectare | 45 |
| Construction area | m2 | 9200 | |
| Storage covering | m2 | 10000 |
| No. | Index content | unit | Index value |
| I | Name | | AAC block |
| Production scale(annual capacity) | | 350,000m3; | |
| Specification(cake: 6.0x1.5x0.6) | m | China national standard(GB) | |
| II | Working system(three-shift continuous weekly production) | | 300 days / year 22.5 hours / day 7.5 hours / shift |
| III | Main raw material consumption | | |
| 1. sand | Ton / year | 147000 | |
| 2.lime | Ton / year | 35700 | |
| 3. gypsum | Ton / year | 6300 | |
| 4.cement | Ton / year | 21000 | |
| IV | Total capacity (ball mill power) | KW | 1650（815） |
| V | Annual power consumption | 10,000ＫＷ.h | 373.62 |
| VI | Annual water consumption | Ton | 178500 |
| VII | Annual gas consumption | Ton | 52500 |
| VIII | Single-shift operators(including forklift and boiler gas distribution) | people | 16 |
| IX | Total plant construction area | hectare | 50 |
| Construction area | m2 | 10000 | |
| Storage covering | m2 | 12000 |
AAC PRODUCTION
Mixing period 5-6 minutes
Pouring slurry temperature 40-45℃
Cake curing time 2.5-3.0h
Cake curing temperature 45～55℃
Cake strength after curing 0.15～0.18MPa
Autoclaved curing system
Before-after autoclave 0.5h
Vacuumize 0.5h(0～-0.06MPa)
Listing pressure 1.5h(-0.06～1.3MPa)
Constant pressure 8h(1.3MPa)
Releasing pressure 1.5h(1.3～0MPa)
total 12h
AAC PRODUCING PROCESS
(1)The lime and gypsum will be crashed and ball milled after entering the factory, batch production for this section working system. The raw materials is continuous crashed into grain which granularity is less than or equal to 25mm, and then be put in the storage respectively through 3-pass splitting by bucket elevator. Lime and gypsum-grain will be fed in proportion through speed belt scale and into ball mill for mixture levitation through the respective baiting splitting, When the fineness reached 3500 ~ 4000cm2 / g, the lime and gypsum-grain will be sent into cement silo through bucket elevator for storage.
(2) The sand is transported to stacking place by dump truck for use.
(3) Sand will be transported to the hopper by loader car, then after measuring be transported to wet ball miller for milling by the belt conveyor, milled to mortar and be transported to storage tank stand-by through beating pool.
(4)Mortar poured into slurry measurement through slurry pump, the cement transported into powder measurement through screw conveyor; The measured mortar, cement poured into pouring mixer according to ratio order for mixing, the amount of steam passed into mixer based on process requirements, slurry temperature in the mixer reached about 40 ~ 45 ℃, mixing time is about 3 ~ 4mins, open the lower valve of aluminum paste mixer, make it flow into pouring mixer for mixing, mixing time is not more than 40s, then the slurry poured into mold. The whole period is about 5 to 6mins.
(5) The poured mold car transfers to curing area for gas-forming & initial setting, temperature in curing room is about 40 to 45 ℃, curing for 150 to 180mins, the mold car is pull out of curing room when reached the cutting strength.
(6)Mould will be transported to the cutting area when the curing reach to cutting requirements, turning table separates the mould and turns the cake to 90°spaced on the cutting car. The car carried cake achieves six sides cutting through horizontal and vertical cutting process(length±3mm～width±1mm～+1mm).
(7) Put the cake on the semi-finished product turning table by crane after cutting, the cake turned to 90 ° by turning table to be peeled the bottom & top leather, then be turned again to original position, next be stacked on the steam curing car by the semi-finished product stacker, marshaled steam curing car be put into the autoclave for high temperature (200 ℃), high pressure (1.3 MPa), autoclave (about 12 hours). Sweep gas in the autoclave be sent to curing area by the pipe.
(8) Finished curing cake will be combined, divided, transfer and packaging after classified placing, separating and clamping treatment. Then sent the after-package cake to the storage yard by forklift. Finished product separated bottom plates will be transported to compound die area by curing car for mould car compounding. After cleaning and oil brushed, the curing car will be poured for re-use. Then back to the curing car and process the autoclave curing after stacking and grouping.
(9) The recycled waste in production can be made into waste slurry by
waste mixer , the stored waste slurry can be reused with raw material.
| Name | AAC block |
| Weight | 300~600 Kg/m3(control led by formula) |
| After autoclave compressive strength | average value;3.5MPa, Min. value<=2.8Mpa |
| Drying shrinkage value | Measured under condition of rapid method: 0.8mm/m Measured under condition of standard method: 0.5mm/m |
| Frost-resistance | After the cycle of freezing and thawing for 15 times,weight loss: 5%,strength loss: 20% |
| Coefficient of thermal conductivity | 0.14~0.16W/m.k |
