Processing Technology For Artificial Sand Making

Summary

In recent years, with the rapid development of China's highways, high-speed railways, urbanization and other constructions, the demand for sand and gravel is increasing, and the natural sand and gravel in most areas have been exhausted; especiall

In recent years, with the rapid development of China's highways, high-speed railways, urbanization and other constructions, the demand for sand and gravel is increasing, and the natural sand and gravel in most areas have been exhausted; especially in the recent strict environmental protection policy , Prohibition or restriction of sand and gravel mining, the supply of sand and gravel raw materials is in short supply, and the price is soaring. Therefore, more and more artificial sand and gravel aggregates are used in various concrete industries. At present, the amount of artificial artificial sand and gravel aggregates made in China is early and has already exceeded the amount of natural sand and gravel raw materials.

Artificial sand processing technology

At present, there are mainly three kinds of processing technology for artificial sand production: wet production process, dry production process and semi-dry production process.

1. Wet processing technology

Wet processing technology refers to the use of water to wash in the process of material screening and crushing, and to cooperate with the stone washing machine and sand washing machine to wash the coarse and fine aggregates. The wet processing technology is generally used when the raw material contains more mud or weak particles. When the content of the finished sand and stone powder is too high, some of the stone powder can also be removed by wet production. According to the different nature of the soil contained in the raw materials, sand washing methods can be divided into sieve surface washing and sand washing machine cleaning. The specific cleaning method should be determined by comprehensive analysis based on factors such as the mud content of the raw materials, the nature of the soil, and the amount of treatment required.

The advantages of the wet production process are: less dust pollution and high washing and screening efficiency. Disadvantages are large water consumption, high cost of artificial sand and fine powder recovery and sewage treatment, serious loss of fine sand and powder, and difficulty in dewatering of finished sand; when using vertical impact crushing to make artificial sand, the sand formation rate is low. The wet production process is suitable for applications in areas with high temperatures and abundant water resources in the south; it is not suitable for applications in northern areas where water resources are severely lacking and freezing in winter.

2. Semi-dry processing technology

Generally refers to the production process before wet. That is, the pre-screening is produced by a wet method and the moisture content of the discharged material is controlled, and the shaping sand screening system uses a dry production process.

Advantages: the water consumption is relatively less than the wet method, the waste water treatment capacity is not large, the stone powder loss is less, and the dust pollution is also less.

Disadvantages: after washing the raw materials for sand making, they must be dehydrated mechanically or for a long time to ensure that the moisture content of the raw materials entering the sand making machine is not more than 3%, otherwise the sand making rate and screening efficiency of the sand making machine will be low. It is mainly suitable for the sand of hydraulic compacted concrete dams with high powder content, which is mainly suitable for the low mud content of the raw materials and the finished sand.

3. Dry processing technology

It means that except for the spray water used in individual dust removal processes, the entire production process basically uses no water.

Advantages: no or very little water consumption, less loss of stone powder, mainly used for raw material cleaning, artificial sand and stone system with high sand formation rate and low stone powder content.

Disadvantages:

The drought in summer in the northern part of China is severely deficient in water, and the winter is extremely cold and freezing, which is particularly suitable for dry production processes. With the gradual strictness of environmental protection requirements in China, especially China's cement industry has entered the large-scale aggregate processing industry, and further promoted the process of industrialization of aggregates.

Artificial sand and stone processing equipment

Whether it is dry, wet or semi-dry in manual sand making, its crushing, screening and sand making equipment are almost the same.

Processing technology equipment is generally:

Feeder-soil removal-coarse crushing-medium and fine crushing-screening-shaping sand-screening-fine powder separation-online monitoring.

1. Crushing and screening

According to the different types of raw materials for artificial sand and stone, the coarse and medium crushing equipment is different:

(1) When the artificial sandstone mother rock is lime and other medium soft materials, the impact crusher can be used for coarse crushing and medium fine crushing;

(2) When the artificial sandstone mother rock is hard rock such as granite, coarse crushing generally adopts jaw type or gyratory crusher, and medium and fine crushing adopts cone crusher.

2. Plastic sand making, sieving and fine powder separation

The -40 mm clean aggregate produced by multiple crushing and sieving in the early stage enters the shaping sand system. The shaping sand making equipment generally adopts the vertical shaft impact crusher. Its shaping sand making principle is that part or all of the shaping sand making raw material enters the high-speed rotating impeller and accelerates rapidly. Raw materials accumulated in the surrounding overflow or vortex cavity are repeatedly impacted at high speed to break and shape the sand. After screening and fine powder separation system, the qualified artificial sandstone is processed; fine powder separation is based on processing Different processes are divided into wet sand washing-sewage treatment and dry fine powder separation-dust removal.

(1) Wet sand washing sewage treatment system

Wet sand washing generally adopts a flat layout. The sieved sand flows into the sand washing machine to wash the sand. The washed fine powder and soil enter the fine sand recovery and dehydration integrated system for fine sand recovery; the separated mud and stone powder enter The high-efficiency thickener concentrates and dehydrates, and the concentrated sediment powder is pressed into a mud cake through the filter press; the overflow of the thickener and the pressurized clean water are recycled; the recovered fine sand and the sifted coarse sand are combined and piled up for dewatering.

Wet process artificial sand making and sewage treatment equipment are generally twice the dry method, the operating cost is also nearly twice, and the equipment covers an area of ​​about 2-3 times. Due to equipment investment, high land occupation rents, and extremely high costs for sewage treatment and dewatering waste residue discharge, the production model of artificial sand production in Japan in the 1990s changed from wet to dry. After 2010 in China, dry sand production has also developed rapidly.

(2) Dry fine powder separation and dust removal

The dry sand fine powder separation system can be set before or after sieving. The plastic sand making machine and the sieving fine powder separation system are connected to the large dust collector through pipes to select the extra fine powder in the sand. Collected by the dust collector, concentrated and stored in the fine powder tank, regularly transported out of the tanker for later application; the sifted sand can be evenly mixed by adding water to the wet mixer to reach a saturated surface dryness, used for sand in concrete mixing stations; It can be directly put into the warehouse without going through the mixing machine, and used for dry mixing mortar sand.

Dry sand-shaping can be arranged in a floor-standing configuration, because the floor-standing equipment is only one-fifth of the traditional wet method and one-third of the traditional dry method; The stand-type artificial sand making system is very suitable for being built together with a concrete mixing station or a dry-mixed mortar mixing station to form a two-in-one or a three-in-one combination system to reduce the cost of finished sand and stone transfer and the storage facilities of the rear warehouse.

Pre: Failure Of The Lubrication System Of Cone Crusher

Next: Performance Characteristics Of Artificial Sand Making Equipment

Other Case