Beneficiation and processing technology of cement limestone

The limestone used for cement production requires a particle size of 30-80 mm. The chemical composition requirements are shown in the table below.

China's cement limestone ore is of good quality. Some larger cement limestone mines require only simple crushing and sieving of the ore to obtain a qualified product. Some limestones with good crystallinity, high whiteness and pure quality can be processed into super coarse calcium carbonate by superfine pulverization, or calcined into lime, and then carbonized to obtain precipitated (light) calcium carbonate.
The production process of general cement limestone mine is: raw ore → smashing → vibrating screening → large (or small) limestone. For limestone containing clay or mud, it is necessary to introduce a washing process before crushing.
The processing technology of heavy calcium carbonate is firstly crushed by high-quality limestone, processed into powder by wet grinding (or dry grinding), and then processed by filtration, drying and ultra-fine pulverization. Dry grinding does not require filtration and drying.
The limestone coarse crushing generally adopts the jaw crusher, and the medium and fine crushing adopts the cone crusher , the impact crusher , the hammer crusher, etc., the ultrafine crushing common high pressure roller mill, the high speed impact mill, the jet mill and the like. Limestone washing is generally carried out by a cylinder washing machine or a tank washing machine.

Gamma lab Nitrogen Generator is suitable for lab use, it makes use of pressure swing adsorption technology, separating and collecting nitrogen from air. It is easy to operate, plug and play, one simple push on starting button, nitrogen generator begin to work.

Mini Lab Nitrogen Gas Plant

Laboratory Nitrogen Generator is one kind of Cabinet Nitrogen Generator.  Its size is within 850 x 920 x 1100 mm, weight within 155 kg. Its details are as below:


2 Detailed technical specification


2.1 Compressed air consumption

The generator consumes a maximum of 115 slpm of compressed air to generate the required N2 flow. Air source is not included in this product.

 

2.2. Air supply pressure

Minimum air supply pressure shall be externally regulated to 600 kPa.  

 

2.3. Air quality

This Generator is provided with one full set of FESTO filters, the air supplied to the Generator still need to be dry and oil-free.

 

2.4. N2 output

2.4.1. Quantity of N2 generate: the generator is capable of deliver 25 slpm nitrogen.

2.4.2. Delivery pressure: the generator delivers N2 at a pressure greater than 450 kPa.  

2.4.3. O2 contamination level: O2 level in the N2 stream is not exceed 0.5%, and does not vary from peak to trough by more than 5% of the absolute concentration.

  

2.5 Dimensions

With package, the Generator size: 850 mm (Length)x 920 mm (width)x 1100 mm(height).  

 

2.6 Weight

With package, the Generator weight is not more than 155 kg.

 

2.7 Wheels

The Generator is fitted with 2 fixed wheels at the rear and 2 swivel wheels with brakes at the front

 

2.8 Connection to power supply

The Generator has a panel mounted connector on the rear panel

• Current capacity at maximum temperature 2.5A<Imax<3.5A ( the power supply is capable of supplying 2.5A nominal)

• Jack plug, 5.5 x 2.5 x 9.5 mm, positive on the centre pin

• Maximum operating voltage at maximum temperature 30VDC.  

• Minimum number of insertions/extractions while maintaining contact resistance specification AND without mechanical failure: > 5000  

• Maximum contact resistance after specified minimum insertions: 30milliohms maximum  

• Insulation resistance: min 100MegaOhms after environmental and durability tests  

• Dielectric withstand Voltage : Min 500V for 60s

• Operating temperature range: -20 deg C to +70 deg C   

 

2.9 Indicator

The Generator has a pushbutton illuminated switch on the front panel

• Button to be flush mounting or recessed into a bezel to avoid damage

• High corrosion resistance, either plastic or stainless steel body  

• No symbol on button

• Size of button and bezel to be ~ 22mm to 30mm

• Mechanical Endurance : > 1000000 activations without mechanical failure

• Electrical Endurance : > 100000 cycles at maximum current and maintaining maximum specified contact resistance• Action mechanism : push on – push off

 

• Current handling capability : 4A DC min break, 4A DC min Make, inductive load (double the maximum expected current demand to give good lifetime)

• Maximum DC Working voltage : at least 40V DC

• Illumination type and color : LED, green

• Illumination Operating voltage: 24VDC

• Operating Temperature Range: -20deg C to +70 degC

• Terminal type : either screw terminal or 6.5mm spade type terminals  

 

2.10. Solenoids

The solenoids on the gas control valves is 24 VDC.

 

2.11. Operation

2.11.1. Operating cycle

A typical operating cycle for the Generator is 1 start per day and then run for 8 hours per day, which is equivalent to 2000 hours of operation per year. Depending upon the particular site, operating time could be anywhere between 0 and 24 hours per day.  

2.11.2. Operation at shutdown

When the power is turned off, the pressure vessels is maintained in the pressurized state by closing the two exhaust valves.  

 

2.12. Start up

2.12.1. Start up time

Start up times means the time from start up to producing qualified nitrogen.

The time to complete start up is less than 15 minutes.  

 

2.13. Gas connections

The two external gas connections on the Generator, Air In and N2 Out, are constructed from brass and are to suit ¼" (6.35 mm) OD tubing. There are labeling in English next to these connections, [Air In" and [N2 Out", as part of the rating label.

 

2.14. Environmental requirements

2.14.1. Operating temperatures

The Generator is normally operated within performance specification over the temperature range:

10ºC - 35ºC from 0 – 3000 m, and 10ºC - 25ºC from 3000 – 4500 m

The Generator can operate safely over the temperature range:

5ºC - 35ºC from 0 – 3000 m, and 5ºC - 25ºC from 3000 – 4500 m

 

2.14.2. Noise level requirements

Noise level from the Generator is less than 72dBa at 1m distance. This is achieved by fitting silencers on the exhaust vents.

 

2.15. Life Requirements

The Generator can operate with a mean time between failure of 5 years minimum.

Lab Use Nitrogen Generator

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Shandong Gamma Gas Engineering Co. Ltd. , https://www.gammagas.com