CN109569837B - A grinding process for treating nickel-copper sulfide ore - Google Patents

Abstract

The invention discloses a grinding process for treating nickel-copper sulfide ore, and belongs to the technical field of metal mineral processing. The specific process steps of the grinding process are: semi-autogenous grinding→wet screening→stone crushing→cyclone classification→ball milling classification. The invention uses semi-autogenous grinding equipment for crushing, changes the original crushing method of the ore, and simplifies the production process. It reduces the excessive crushing of metal minerals, reduces the pollution of iron to useful minerals, and creates more powerful conditions for flotation. The content of the ‑10μm particle size that is not suitable for flotation process treatment is reduced by about 5%; the number of equipment is small, and the production cost is low; the back-and-forth transportation of ore in the production process is reduced, the dust pollution to the working environment of employees is avoided, and occupational diseases of personnel are reduced risk.

Description

A grinding process for treating nickel-copper sulfide ore

technical field

The invention relates to the technical field of metal mineral processing, in particular to a new ore grinding process, in particular to a grinding process for processing nickel-copper sulfide ore.

Background technique

The purpose of mineral processing is to maximize the enrichment and recovery of useful minerals from primary ores. In the traditional mineral processing process, the main crushing and grinding processes are: crushing and screening + grinding and classification. Therefore, the pulverization degree of the ore directly affects the technical and economic indicators of the beneficiation. If the particle size is too coarse, the target minerals cannot be fully dissociated from the gangue minerals and cannot meet the technical requirements of subsequent sorting; if the crushed particle size is too fine, the target minerals are too crushed and enter the sorting operation together with the gangue minerals. , so that the target minerals cannot be separated from the gangue minerals, and the purpose of useful resource enrichment and efficient recovery cannot be achieved.

Taking the traditional grinding process of a nickel-copper sulfide ore as an example: the proportion of ore mined in the mine with a particle size of +500mm accounts for about 70%. When the particle size reaches below 60mm, it is screened, the products on the screen are finely crushed, and the products under the screen are used as the feed for grinding; after the products on the screen are finely crushed, the particle size of the products reaches 12mm, and then enter the screening; the products under the screen enter the grinding operation , the product on the sieve is returned to fine crushing, and this cycle is repeated. The crushed qualified products enter the first ball mill, and the ore discharged from the first ball mill is classified for one time. After the first classification, the sand is returned to the first ball mill, and the overflow ore after the first classification is classified for the second time. The secondary classified overflow ore enters the flotation operation, and the secondary classified sediment enters the secondary ball milling; after the secondary ball milling, the discharged ore returns to the secondary classification, the overflow ore enters the flotation operation, and the sediment returns to the secondary ball milling (see figure 1).

As can be seen from Figure 1, the traditional crushing process is a three-stage closed-circuit process, and the grinding process is a two-stage closed-circuit process. The specific problems that exist are:

1. The process is complex, the operation process is long, and the number of ore cycles is large, resulting in low fineness of the crushed products and unreasonable and unstable particle composition. As shown in Table 1, the grinding fineness is 65.6%, the content of -74~+15μm particle size suitable for flotation process treatment in the qualified particle size only accounts for 28.24%, and the content of grade below -15μm unsuitable for flotation process treatment accounts for 28.24%. 37.36%.

Table 1 Product particle size distribution and content table of traditional grinding process (%)

2. The number of equipment is large, the management is difficult, the energy consumption is large, and the production cost is high.

3. In the crushing stage, a large amount of dust is generated during the transportation, crushing and screening of ore, which has a great impact on the health of personnel.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the above-mentioned defects of the prior art, and provide a grinding process for treating nickel-copper sulfide ore with high product quality, low cost and high personnel safety.

The object of the present invention is achieved through the following technical solutions: a grinding process for processing nickel-copper sulfide ore, specifically comprising the following steps:

(1) Semi-autogenous grinding: After the nickel-copper sulfide ore is initially crushed underground to a particle size of ≤250mm, it is fed into a semi-autogenous mill for grinding by a belt conveyor, and the semi-autogenous mill is produced to discharge the ore. The ore discharge is ore pulp with a concentration of 65-70% by weight;

(2) Wet screening: the ore discharged from the semi-autogenous mill in step (1) is fed into the wet screening machine for screening, the stubborn stones that are difficult to grind are on the screen, and the fine-grained products are found under the screen. The ore particles with particle size ≤6mm account for 80-90% in the product;

(3) Crushing of stubborn stone: The stubborn stone in step (2) is fed into the stubborn stone crusher by the belt conveyor for crushing. The belt conveyor returns to the semi-autogenous mill for circulating grinding;

(4) Cyclone classification: The fine-grained product in step (2) is pumped into the hydrocyclone for classification, and the pressure of the cyclone is 0.7-0.75Mpa, and overflow ore and sand settling are produced, and the overflow ore flows to stirring. tank, add flotation reagents and stir evenly as raw materials for flotation;

(5) Ball mill classification: the sedimented sand in step (4) is fed into the ball mill for grinding, and the filling rate of the grinding medium of the ball mill is 30-35%. The mineral products are pumped into the hydrocyclone for classification.

As a further optimization of the technical solution of the present invention, in the above step (1), during grinding, the ore feeding amount is 460 tons/hour, the grinding concentration is 75%, the grinding work index is 15.9-17.65Kwh/t, and the grinding medium is 15.9-17.65Kwh/t. The filling rate is 8-15%, and the water pressure of the grinding feed water is 0.35-0.45Mpa. Under these conditions, the consumption of steel balls and the wear of the lining plate of the semi-autogenous mill are the smallest, the key parameters of the semi-autogenous mill such as power and current are stable, and the output of stubborn stones is constant, which creates a good situation for the stable operation of the subsequent ball mill classification. conditions of.

In step (4), the overflow ore is ore pulp with a weight percent concentration of 25-27%, and the ore particles with a particle size of 0.074 mm in the ore slurry account for 70-75%; the sand settling is 65-75% by weight. , the size of the ore particles in the slurry is less than or equal to 6mm. Under this condition, the amount of slurry in the ball mill + cyclone classification link is stable, the slurry pump runs smoothly, the cyclone classification pressure fluctuation is small, and the classification effect is the best, which creates good conditions for the stable operation of the subsequent flotation.

The crushing and grinding process of the present invention uses semi-autogenous grinding equipment for crushing, changes the original crushing method of the ore, simplifies the production process, and has the following advantages compared with the traditional crushing and grinding process of nickel-copper sulfide ore:

1. The particle size of the grinding products is stable and the particle size distribution is more reasonable, which reduces the excessive crushing of metal minerals, reduces the pollution of iron to useful minerals, and creates more powerful conditions for flotation. Under the conditions that the ore feeding rate is 460 tons/hour, the grinding concentration is 70%, the grinding work index is 17.65Kwh/t, the filling rate of the grinding medium is 15%, and the grinding water pressure is 0.45Mpa, the cyclone The overflow ore was sampled, and the particle size distribution test was carried out. The test results are shown in Table 2.

As can be seen from the table, the grinding process of the present invention increases the content of the -74-+10 μm particle size suitable for the enrichment and recovery of the flotation process by 14%, while the content of the -10 μm particle size not suitable for the flotation process is reduced by about 5%. %.

Table 2 Grain size distribution content table (%) of grinding products in the semi-autogenous grinding process of the present invention

2. The device of the present invention is small in number, convenient in configuration, small in land occupation, and low in investment.

3. The production process is easy to manage, high production efficiency, low production cost, easy to realize automatic control, and the labor intensity of operators is reduced.

4. It reduces the back-and-forth transportation of ore in the production process, avoids the occurrence of dust and blockage in the intermediate links, completely improves the working environment of employees, and reduces the risk of occupational diseases.

Description of drawings

Fig. 1 is the grinding process flow chart of existing nickel-copper sulfide ore;

Fig. 2 is the grinding process flow chart of nickel-copper sulfide ore of the present invention.

Detailed ways

The grinding process of the nickel-copper sulfide ore of the present invention will be further described in detail below through specific examples.

The process flow in the following embodiments of the present invention all refer to FIG. 2 .

Example 1

The ore feeding rate is 460 tons/hour, the ore feeding particle size is 100-250 mm, accounting for 30%, the nickel grade of the ore is 0.85%, and the Platts hardness of the ore is 12.5.

Step (1): First, the nickel-copper sulfide ore with the above particle size and hardness is fed into the semi-autogenous mill for grinding using a belt conveyor. The grinding work index is 17.65 Kwh/t, the medium filling rate is 15%, and the semi-autogenous grinding is performed. The water supply pressure is 0.45Mpa. Output the ore discharged from the semi-autogenous mill, and the ore discharged from the semi-autogenous mill is ore pulp with a concentration of 70% by weight;

Step (2): The semi-autogenous mill in step (1) is fed into the wet sieving machine for screening, the stubborn stones that are difficult to grind are on the screen, and the fine-grained product is under the sieve. Mineral particles with particle size ≤6mm account for 80%;

Step (3): The stubborn stone (on-screen amount) in step (2) is fed into the stubborn stone crusher by the belt conveyor for crushing. The product is returned to the semi-autogenous mill through the belt conveyor for cyclic grinding;

Step (4): Pump the fine-grained product (under sieve amount) in step (2) into the hydrocyclone for classification, the pressure of the cyclone is 0.71Mpa, and the overflow ore and sand settling are produced, and the overflow ore flows to Stirring tank, add flotation agent and stir evenly as raw material for flotation;

Step (5): feeding the sedimented sand in step (4) into the ball mill for grinding, the filling rate of the grinding medium of the ball mill is 30%, and the discharge product is ore pulp with a concentration of 58% by weight, and the discharge product is pumped into hydraulic Cyclone for classification.

After this semi-autogenous grinding → stubborn stone crushing → ball milling process, the composition of the overflow ore size is shown in Table 3 below:

Table 3 Composition of overflow ore particle size (%) in Example 1

It can be seen from the above table that the range of particle size suitable for flotation is: -74~10μm, and the average proportion is 60.85%, which meets the particle size requirement of 60% of the first-stage flotation operation.

Example 2

The ore feeding rate is 460 tons/hour, the ore feeding particle size is 100-250 mm, accounting for 25%, the nickel grade of the ore is 0.78%, and the Platts hardness of the ore is 12.

Step (1): First, the nickel-copper sulfide ore with the above particle size and hardness is fed into the semi-autogenous mill for grinding using a belt conveyor. The grinding power index is 16.7 Kwh/t, the medium filling rate is 12%, and the semi-autogenous grinding The water supply pressure is 0.43Mpa. The semi-autogenous mill discharges ore, and the semi-autogenous mill discharges ore pulp with a concentration of 68% by weight;

Step (2): The semi-autogenous mill in step (1) is fed into the wet sieving machine for screening, the stubborn stones that are difficult to grind are on the screen, and the fine-grained product is under the sieve. Mineral particles with particle size ≤6mm account for 85%;

Step (3): The stubborn stone (amount on the screen) in the step (2) is fed into the stubborn stone crusher by the belt conveyor for crushing. The product is returned to the semi-autogenous mill through the belt conveyor for cyclic grinding;

Step (4): Pump the fine-grained product (screening amount) in step (2) into the hydrocyclone for classification, the pressure of the cyclone is 0.73Mpa, and the overflow ore and sand settling are produced, and the overflow ore flows to Stirring tank, add flotation agent and stir evenly as raw material for flotation;

Step (5): feeding the sedimented sand in step (4) into the ball mill for grinding, the filling rate of the grinding medium of the ball mill is 33%, the ore discharge product is ore slurry with a weight percentage concentration of 62%, and the ore discharge product is pumped into hydraulic Cyclone for classification.

After this semi-autogenous grinding → stubborn stone crushing → ball milling process, the composition of the overflow particle size produced is shown in Table 4 below:

Table 4 Composition of overflow ore particle size (%) in Example 2

It can be seen from the above table that the range of particle size suitable for flotation is: -74~10μm, with an average proportion of 62.29%, which meets the particle size requirement of 60% for the first-stage flotation operation.

Example 3

The ore feeding rate is 460 tons/hour, the ore feeding particle size is 100-250 mm, accounting for 20%, the nickel grade of the ore is 0.65%, and the Platts hardness of the ore is 11.7.

Step (1): First, the nickel-copper sulfide ore with the above particle size and hardness is fed into the semi-autogenous mill for grinding using a belt conveyor. The grinding work index is 17.65 Kwh/t, the medium filling rate is 10%, and the semi-autogenous grinding The water supply pressure is 0.41Mpa. The semi-autogenous mill discharges ore, and the semi-autogenous mill discharges the ore pulp with a concentration of 65% by weight;

Step (2): The semi-autogenous mill in step (1) is fed into the wet sieving machine for screening, the stubborn stones that are difficult to grind are on the screen, and the fine-grained product is under the sieve. Mineral particles with particle size ≤6mm account for 90%;

Step (3): The stubborn stone (on-screen amount) in step (2) is fed into the stubborn stone crusher by the belt conveyor for crushing. The product is returned to the semi-autogenous mill through the belt conveyor for cyclic grinding;

Step (4): Pump the fine-grained product (screening amount) in step (2) into the hydrocyclone for classification, the pressure of the cyclone is 0.75Mpa, and the overflow ore and sand settling are produced, and the overflow ore flows to Stirring tank, add flotation agent and stir evenly as raw material for flotation;

Step (5): feeding the sedimented sand in step (4) into the ball mill for grinding, the filling rate of the grinding medium of the ball mill is 35%, the ore discharge product is ore slurry with a weight percentage concentration of 65%, and the ore discharge product is pumped into hydraulic Cyclone for classification.

After this semi-autogenous grinding → stubborn stone crushing → ball milling process, the composition of the overflow particle size produced is shown in Table 5 below:

Table 5 Composition of overflow ore particle size (%) in Example 3

It can be seen from the above table that the range of particle size suitable for flotation is: -74 ~ 10μm, with an average proportion of 60.33%, which meets the particle size requirement of 60% for the first-stage flotation operation.

Claims (2)

1. A crushing and grinding process for treating nickel-copper sulfide ore is characterized by comprising the following steps:

(1) semi-autogenous grinding: primarily crushing nickel-copper sulfide ore underground until the granularity is less than or equal to 250mm, feeding the nickel-copper sulfide ore into a semi-autogenous mill by using a belt conveyor for grinding, and producing ore discharge of the semi-autogenous mill, wherein the ore discharge of the semi-autogenous mill is ore pulp with the weight percentage concentration of 65-70%; when grinding ore, the ore feeding amount is 460 tons/hour, the ore grinding concentration is 75 percent, the ore grinding work index is 15.9-17.65Kwh/t, the ore grinding medium filling rate is 8-15 percent, and the ore grinding water supply pressure is 0.35-0.45 Mpa;

(2) wet screening: feeding the ore discharged by the semi-autogenous mill in the step (1) into a wet sieving machine for sieving, wherein stubborn stones which are difficult to grind are on the sieve, fine grain products are under the sieve, and ore grains with the grain size of less than or equal to 6mm in the fine grain products account for 80-90% of the total weight of the ore;

(3) breaking hard rock: feeding the hard rock in the step (2) into a hard rock crusher by a belt conveyor for crushing, wherein when the ore feeding amount is 46-92 tons/hour, a crushed product with the granularity less than or equal to 15mm is produced, and the crushed product returns to a semi-autogenous mill by the belt conveyor for circular ore grinding;

(4) cyclone classification: pumping the fine product obtained in the step (2) into a hydrocyclone for classification, wherein the pressure of the hydrocyclone is 0.7-0.75Mpa, producing overflow ore and settled sand, enabling the overflow ore to automatically flow to a stirring tank, adding a flotation reagent, and uniformly stirring to obtain a flotation raw material;

(5) ball milling and grading: and (4) automatically feeding the settled sand in the step (4) into a ball mill for grinding, wherein the filling rate of a grinding medium of the ball mill is 30-35%, an ore discharge product is ore pulp with the weight percentage concentration of 58-65%, and the ore discharge product is pumped into a hydrocyclone for classification.

2. A comminution process for the treatment of nickel copper sulphide ore according to claim 1 in which in step (4) the overflow ore is a slurry having a concentration of 25 to 27% by weight, with 70 to 75% being the proportion of particles having a particle size of 0.074 mm; the settled sand is ore pulp with the weight percentage concentration of 65-75%, and the grain diameter of ore grains in the ore pulp is less than or equal to 6 mm.

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