How to determine the cyclic load in closed-circuit grinding equipment?

In closed-circuit grinding, the coarse-grained grade that needs to be returned to the grinding mill for re-grinding by grading is called cyclic loading (or sand returning), and its size can be expressed by two methods, namely absolute quantity (t/h) and relative quantity ( The ratio of the quality of the returned sand to the original ore quality is called the return sand ratio or the cyclic load factor). Since the appropriate cyclic load will directly affect the indicators of grinding operations, it should be measured periodically.

There are two commonly used measurement methods: (1) Screening method. The sieving method is used to determine the cyclic load from the classifier to the ore (milling ore discharge), sand return and overflow, and take a representative sample screening analysis to obtain a calculation level of three products (such as -0.074mm). The fractional content (yield) is then calculated according to the principle of the balance of the entry and exit in the classification operation according to the calculation level:

In the formula, , - is the calculated grade (such as -0.074mm) yield, % in graded ore, overflow and return sand. (2) Mass fraction method. Because the sieve test method measures the cyclic load, it needs to be sampled and sieved, and the cycle is long. The mass fraction method can be used for rapid determination in production. The method is to sample the graded ore, return sand and overflow, and determine the mass fraction of the three products (the mass fraction pot can be used). Then calculate as follows:

In the formula - the mass fraction or liquid-solid ratio of the three products of the classifier feeding, overflowing and returning sand respectively.

API 5L Pipe

Yangzhou Chengde have the certification of API 5L and API 5CT, so we permit to produce and sell the API pipes with the Chengde brand directly.

We can produce the API pipes according to the API 5L standard, such as the GR.B steel pipe, X42 steel pipe, X52 steel pipe, X65 steel pipe, X70 steel pipe, X80 steel pipe, etc.

The follow table is our main reference list on the API 5L product

Customer	PJT name	Grade and size range	Quantity(MT)
Keppel	N/A	X52/X65 PSL2 OD (244.5~457)x(12.7~38.1) mm	3650
Shell	NYHAMNA	X52/GR6/X52 PSL2 OD (219~609)x(12.7~65) mm	968
SBM	SAXI BATUQUE	X52/X65 PSL2 OD (219~660)x(25.4~70) mm	1100
Exxon Mobil	Oil Field Chayvo	X60PSL2/GR.6 OD(273.1~609.6)x(15.09~76.2)	310
Dalian Shipping Building/ZPMC	Leg bracing pipe	X52~X80 PSL2 OD (159~955) x(10~51)mm	7050
PETROBRAS	PMXL1 MEXILHAO	X52/X60/X65 PSL2 OD (219~762)x(18.3~69.85)mm	850

The Piercing and rolling technology of Chengde possesses a number of patents in designing and manufacturing the equipment, and has improved in lots of areas targeting better performance and efficiency, which has distinguished itself from the peers.

Advantages of our pipes

1 Uniform mechanical properties and dimensions in longitudinal& transversal directions and better surface condition

2 Minimum Order Quantity (MOQ) as low as ONE piece AND Huge size scope to accommodate the project requirements (8"~48``).

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4 30 years experience and approvals with Major EPCs/OEMs/Clients in the supplier chain.

API 5L 5CT Certification

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