In the beneficiation process of large mines, the use of reagents is a dynamic balance. Some medicines need to be "introduced" - increasing the dosage and enhancing the effect; Some medicines need to be "withdrawn" - reducing the dosage or even completely stopping use. When to enter and when to exit, how much to enter and how much to exit, are questions that mineral processing engineers ponder every day.

Today we will talk about the "in" and "out" management of mineral processing reagents.

Why do we need to 'enter'?

There are many reasons for 'entering'. The most common situation is encountering difficult to select ores.

The properties of ores vary greatly. Some are good choices, adding a little potion can bring up the gold; Some are difficult to choose and require increasing the dosage or even switching to stronger drugs to achieve the same effect.

For example, when gold in ore is tightly encapsulated by sulfides, conventional amounts of collectors are often insufficient. At this point, it is necessary to increase the amount of collector or switch to a variety with stronger collection capacity. This is' entering '.

Another situation that requires "advancement" is a decrease in device performance. The steel ball of the grinding machine has worn out, and the ground mineral powder is not fine enough, making it difficult for the medicine to come into contact with the gold particles wrapped inside. Before repairing the equipment, temporarily increasing the dosage of chemicals can partially compensate for the lack of grinding and try to maintain the recovery rate without decreasing.

Changes in water quality are also a common cause of 'ingress'. If there are too many impurities accumulated in the circulating water, some of the chemicals will be consumed. If you don't add enough at this time, the medicine won't be enough. Engineers will increase the dosage of chemicals appropriately based on the results of water quality testing.

Why do we need to 'withdraw'?

'Advance' is to ensure indicators, while 'retreat' is to reduce costs and improve quality.

Adding too much medicine may not necessarily be good. Excessive addition, on the one hand, causes waste and increases costs; On the other hand, it may bring side effects. For example, if there are too many collectors, the selectivity decreases, and impurities that should not float up also come up, causing the concentrate grade to be lowered. Too many inhibitors may also hold down the floating minerals, resulting in a decrease in recovery rate.

So, when the ore becomes easier to select, it is necessary to decisively "retreat" - reduce the dosage of chemicals and restore it to a reasonable level. After the device performance is restored, it is also necessary to promptly "withdraw" - reduce the temporarily increased dosage back.

Another scenario is finding a more efficient medication solution. The original old plan had a large dosage and average effect; The new plan has a smaller dosage and better effect. At this point, it is necessary to 'abandon' the old plan and replace it with a new one. Although this "withdrawal" refers to the withdrawal of the old plan, from the perspective of medication dosage, it is also a "withdrawal" - using less medication to do more things.

What is the basis for 'entering' and 'exiting'?

Relying on intuition to advance and retreat is not enough. Engineers in large mines must have a basis for making decisions.

Laboratory data is an important basis.
The ore has changed, take a sample back to the laboratory for flotation testing first. Compare different dosages of reagents to find the optimal dosage under current ore conditions. With experimental data, there is confidence in adjusting.

Online instrument data is a real-time basis.
The pH value, oxidation-reduction potential, and reagent concentration of the slurry can all be monitored online. Once these parameters deviate from the normal range, the system will automatically sound an alarm to remind the operator to adjust them in a timely manner.

Production indicator data is the basis for verification.
Is there any effect after the adjustment? You can tell by looking at the indicators. The decrease in tailings grade indicates that the adjustment is effective; The increase in concentrate grade indicates that the direction is correct. Indicators are the best judges.

The rhythm of 'in' and 'out'

When to enter and when to exit, rhythm is important.

You can't go in too aggressively.
Increasing the dosage by a large margin at once may cause significant fluctuations in the indicators. The originally smooth running system may become chaotic due to this radical adjustment. The safe approach is to take small steps and run quickly - increase slightly each time, observe the effect before deciding the next step.

You can't retreat too quickly either.
The ore has become easier to select, and if you want to reduce the dosage of chemicals, you also need to gradually reduce it. If the decrease is too fast, the indicator may suddenly decline. It's too late to realize until the indicators have already deteriorated. The same principle applies: reduce the amount slightly each time, observe for a period of time, and confirm that the indicators are stable before continuing to decrease.

Avoid frequent repetition.
Today's increase, tomorrow's decrease, and the day after tomorrow's increase, the entire system has been fluctuating. The operators are at a loss and the indicators cannot be stabilized. Before each adjustment, it is important to consider whether it is necessary? Can we observe again? Is there a better solution?

From 'passive response' to 'active regulation'

Low level medication management is a passive reactive approach - adjustments are made only when the indicators have deteriorated, and adjustments are made after the next time they have deteriorated. This' fire brigade 'style approach always runs behind the problem.

High level pharmaceutical management is proactive regulation - anticipating potential problems and making adjustments in advance before the indicators deteriorate.

What does proactive regulation rely on? Relying on trend analysis. Looking at today's data alone, everything is normal. But looking at the data from several consecutive days together, it may be found that the consumption of a certain medication is slowly increasing. Although it has not yet exceeded the normal range, if this trend continues, it will exceed the standard in a few days. By adjusting in advance, we can nip the problem in the bud.

Active regulation still relies on accumulated experience. The same ore, the same season, the same equipment status, what problems have occurred in the past, and how they were adjusted at that time, these experiences are recorded and organized into knowledge, which can be used to deal with similar situations in advance the next time.

Progress and Retreat in Environmental Protection Transformation

In recent years, large mines have undergone a profound transformation from traditional highly toxic agents to environmentally friendly agents. This transformation is essentially a process of "advancement" and "retreat".

We are returning traditional highly toxic drugs.
Sodium cyanide, highly toxic inhibitors, and collectors are gradually being phased out of the list of chemicals used in large mines. Some are forcibly prohibited by policies, while others are voluntarily abandoned by mines - because the compliance costs and safety risks of using these chemicals are increasing.

We are introducing environmentally friendly alternatives.
New low toxicity and biodegradable agents are entering the pharmaceutical system of large mines. They have higher safety and less environmental pressure. Although their unit price may be slightly higher, their overall cost is not inferior to traditional products.

This' advance 'and' retreat 'are not achieved overnight. Each switching step requires sufficient testing and validation to ensure that the performance of the new agent is not inferior to that of the old agent, and to ensure a stable transition of the entire process system. It's neither urgent nor delayed.

The concept behind "advance" and "retreat"

Entering and exiting are not just technical issues, but also a set of management concepts behind them.

Precision concept. 过去是“多多益善”——反正药不贵，多加一点保险。现在是“刚刚好”——加少了效果不够，加多了浪费且有副作用。找到那个“刚刚好”的点，需要精准的数据支持和精细的控制手段。

Dynamic concept. 没有永远正确的药剂方案。矿石在变、水质在变、气温在变，方案也要跟着变。僵化不变，就是退步。

System concept. 药剂的进与退，不是孤立的行为。它牵一发而动全身。增加一种药剂的用量，可能影响另一种药剂的效果。调整了浮选的药剂方案，可能需要对后续的脱水、尾矿处理环节做相应调整。不能只看局部，要看到全局。

Being able to 'advance' and 'retreat' is the true skill

Engineers who only know how to 'move in' but not 'move back' are not good engineers. If there is a problem, add medication. Who wouldn't? But when can it be reduced back and to what extent is appropriate after adding, that's the time to see the power.

Engineers who only know how to 'retreat' but not 'advance' are not good engineers. By blindly pursuing cost reduction and reducing the amount of chemicals used, the recovery rate and concentrate grade have decreased, and the saved chemical costs are not enough to cover the losses.

A truly excellent beneficiation engineer knows how to assess the situation. When it's time to move in, move forward decisively, and when it's time to retreat, move forward with evidence and retreat with moderation. They don't have a fixed "standard formula" in their hands, only a "dynamic plan" that can be adjusted at any time. This ability is not learned from books, but honed through long-term on-site practice.