THE CALCULATION OF GRINDING BALLS ASSORTMENT FOR GRINDING ZINC

In June 2021, Energosteel received a request for miscalculation of the grinding balls.

It would seem that the classic workings of our company, which for more than 12 years has been specializing in the production and sale of high quality steel grinding balls. The only difference in this request is the grinding material – zinc.

This project is only at the initial miscalculation stage. Therefore, the input data are very limited. It is known that to produce a powder it is necessary to grind pieces of zinc, which have passed the stage of crushing on a hammer crusher. After crushing, the material is more homogeneous and the pieces have geometrical dimensions of 3-5mm. Planned capacity is the grinding of 400 kg per hour. The customer asked for advice on what equipment and grinding balls can be used in these conditions.

Mechanical grinding of compact metals is widespread in powder metallurgy. The grinding can be crushing, abrasion. It is most appropriate to use mechanical grinding in the production of brittle metal powders and alloys such as Si, Be, Cr, Mn, Al alloys with Mg, etc. In our case, it is necessary to scale up viscous plastic metals (Zn, Al, Cu). The difficulty is that they (viscous metals) are mostly crushed rather than destroyed.

Zinc grinding combines crushing and striking (in the case of large particles) and abrasion and

impact (in the case of thin grinding). Consequently, the milling process will consist of two stages:

1. Grinding with steel grinding balls 60-40 mm in diameter;
2. Fine grinding with steel grinding balls 25-30mm.

Given the rather small planned performance, the use of a two-chamber tube ball mill is not advisable. The choice was to use two MH2 mills (1350×1500). These mills are designed for dry grinding of the material, have an internal drum volume of 2.5 m3 and a total load of grinding bodies up to 6.5 tons. The calculation showed that the mill of the first stage would be loaded with an assortment of steel grinding balls with an average diameter of 63 mm. The average diameter of the assembly balls of the second mill shall not exceed 27 mm. In addition, the presence of magnetic separation of the finished material (powder), i.e. the metal formed by abrasion of the ball will be mixed with the zinc powder, which is not desirable.

Many of you will say that in addition to the ball mill, there are other kinds of shredded equipment that can be used in this situation. And everyone will be right. However, today the use of ball mills for material grinding is the optimal solution. Using the steel grinding balls produced by LLC «Plant «Energosteel», you realize the production potential of your own equipment in the most efficient way.