Lead battery recycling at Hosokura Metal Mining
2015/07/08Hosokura Metal Mining Co., Ltd. located in Kurihara City, Miyagi Prefecture, which is specialized in recycling lead battery, used to mine ores containing lead, zinc and silver as Takada Mine and then Hosokura Mine. Itfs a historic smelter that had produced the lead used for producing coins circulated during the Edo period.
The scars of air attacks have been left at the product warehouse in the plant premises, where historical legacy can be felt.
As the smelter shows that Japan used to be self-sufficient as resource-rich country, it should be preserved almost permanently.
Hosokura Mine was closed in 1987. Before or after the year, other domestic mines were also closed one after another.
Switching the raw materials from lead concentrate mainly to lead battery scraps, it turned a recycling smelter in 1996.
Being fully owned by Mitsubishi Materials, the company annually produces 300,000 tons of lead ingot, which is also used to produce lead alloy based on the specification desired by users. Nearly 90% of lead ingot produced by the company is sold to lead battery manufacturers and is also used as radiation shielding sheet at X-ray rooms.
To produce lead, the company consumes 4,000 tons or less of raw materials with car battery scraps being the main.
In addition, it consumes 100 tons of residues containing lead sent from Naoshima Smellter & Refinery of Mitsubishi Materials, the parent company. Antimony trioxide, bismuth ingot and crude silver are also produced through processing the raw materials.
The company has 3 hydro power plants. Purchasing power seasonally in winter, but it sells power to the power company throughout the year as power generation amount exceeds their power consumption.
It also produces drinking water with their water purifying plant.
More than 3,000 employees used to work at the mine and about 10,000 residents lived in the vicinity of it in the period of Hosokura Mine, which distributed electricity, water and foods to them. It still provides local residents with drinking water.
Hoping stable collection of battery scraps
Although the route of SBRA (Lead Acid Storage Battery Recycle Association)fs wide-area certified system is established, the volume of collected scraps has decreased drastically through the system as used car batteries are traded as valuables. The system is nearly-defunct at the moment.
The company collects lead battery scraps mainly in the local Tohoku region (the northeast area of the main island), but it also receives materials from other regions such as Kanto region and Hokkaido region as it canft secure the planned amount only through the collection from the nearby area.
Increasing export from Japan to Korea is one of the causes for difficulties in collecting batteries. Batteries are traded at extremely high prices ignoring LME prices not only as raw materials for recycling. Under such circumstances, according to Mr. Sakuraba, Manager of Purchasing Department of the company, gAround last autumn, as we couldnft collect the planned volume around, the production was affectedh.
Transition of monthly exported battery scrap from 2011 to 2014 (Unit: ton)
In the pretreatment process of battery scraps, the company not only separates domestic and overseas batteries but also sorts each backup storage battery to carry out through quality control of battery cases (resin materials), which are shredded to sell to domestic resin processors.
The company said that a steady collection of battery scraps is the current problem.
gIn assuming that the domestic car battery scrap generation is 15,000-20,000 tons per month, nearly the half of it is exported. Ministry of the Environment canft seem to limit the amount of export under the Basel Convention. If the raw material shortage continues, domestic lead smelters are forced to cut output. However, if storage batteries comes to be installed at home with the proliferation of household solar power systems, raw materials for recycling other than car batteries will increase. We expect ith, Mr. Sakuraba said.
(Edited by Sasaki)