3. SUCCESS STORY REPORT
FOR
LEAD ACID STORAGE BATTERY
MANUFACTURING, SECONDARY LEAD
SMELTING & PROCESSING SECTOR
MARCH 2011

4. Prepared by : Ruby Sinha, Environmental Engineer
West Bengal Pollution Control Board
Prasun Kr. Mondal, Assistant Environmental Engineer
West Bengal Pollution Control Board
Edited by : Amitava Ray, AECEN India Representative
Published by : Subrata Ghosh
Chief Engineer,West Bengal Pollution Control Board
& Nodal Officer, Environment Compliance Assistance Centre
Printed by : S. Antool & Co. Pvt. Ltd.
91, A. P. C.Road, Kolkata-700009

5. 1. INTRODUCTION 4
2. OVERVIEW OF LEADACID BATTERY MANUFACTURING
PROCESS
5
3. VISIT TO HBL POWER SYSTEMS LTD 7
4. CLEANER TECHNOLOGY OPTIONS ADOPTED BY HBL POWER
SYSTEMS LTD
9
5 SECONDARY LEAD SMELTING SECTOR 13
6. CONCLUSION ANDWAY FORWARD 14
7. PHOTOGRAPHS
TABLE OF CONTENTS

7. A. Introduction :
The Environment Compliance Assistance Centre inWest Bengal has selected four SME sectors to
identify the environmental compliance related problems and also to document the success stories in
these sectors in other states of our country. Lead-acid battery and secondary lead smelting sector is
one of these identified four sectors. A two member team of the WBPCB visited the state of Andhra
Pradesh to study the success stories in this sector. The team visited the industry of M/s. HBL Power
Systems Ltd. in Hyderabad which is a pioneer in the field of battery manufacturing.
The use of battery has been increasing as time is passing. The increasing usage is proving its
importance and role. Batteries are gift of science which are given to men. The benefits and
advantages of battery is numerous and countless. These are the real companion of men in today's
world. No one can deny the leading role of battery.
Principal application area of lead is lead - acid batteries which account for about 60% of total
consumption. Lead is produced from primary raw materials as well as secondary raw materials.
The generation of lead bearing scraps/wastes increases with increasing use of batteries. The
importance of secondary lead plants is increasing day by day because lead being a hazardous
substance, recycling from scraps/wastes is the best way to protect the environment from pollution.
Exposure of lead from which battery is made is the primary health concern in battery
manufacturing. Any operation in which battery plates, lead scrap, or oxide is handled may be a
significant source of lead exposure. Airborne dispersion of lead dust via cross drafts, pedestrian and
vehicular traffic and dry sweeping may be an additional source of lead exposure. Lead fumes from
lead pots, torching, burning or other operations where a flame contacts lead, or lead is heated above
the melting point, may also be sources of lead exposure. Controlling the exposure to lead can be
done through engineering controls, administrative actions and personal protective equipments.
5

8. B. General Manufacturing Procedure in Lead Acid Battery Units:
A battery is an electrochemical cell (or enclosed and protected material) that can be charged
electrically to provide a static potential for power or release electrical charge when needed.
A battery generally consists of an anode, a cathode and an electrolyte. Lead-acid batteries, invented
in 1859 by French physicist Gaston Planté, are the oldest type of rechargeable battery.
6
Basic structure of a Lead Acid Batteries are:
i) Positive Plate ii) Negative Plate iii) Electrolyte iv) Separator and other passive components like
terminals, lids, container etc. The plates are made up of g rid / spines from pure lead or alloy of
lead, in which active materials are held in the interstices and take part in the chemical reaction to
supply the energy. The grids or spin es are produced through the casting process.
A typical process flow chart of lead acid battery manufacturing is given below:
Process Flow Chart of Lead Acid Battery

9. C. HBL Power Systems Ltd., Mehboob Nagar, Hyderabad:
State Board Officials visited the unit of M/s. HBL Power Systems Ltd. at Mehboob Nagar,
Hyderabad. HBL is one of the leading manufacturer and supplier of a wide range of batteries. These
batteries are widely used for telecom, aviation, automotive, railways and industries.
This unit manufactures Pb-acid battery. The unit comprises of 77 acre land, out of which one third is
greenery. Unit runs generally in two shifts in a day. Pb ingot and Pb dross are used as main raw
material which are purchased from India, China, South Africa. This unit has production capacity of
1000 batteries per day.
Different types of lead acid batteries are :
Flat plate VRLA
Pure Lead-Tin VRLA
Tubular gel VRLA
Ultra low Maintenance Tubular
Miners Cap Lamp
The unit is an integrated battery manufacturing unit. The unit has its own battery container
manufacturing division as well as used battery recycling division to ensure safe reuse/r ecycle of lead
scraps that are generated from the used batteries.
This unit has following divisions :
1. PMD (Plastic moulding division)
Virgin granules of ABS, PP, LDPE, HDPE are used as raw materials for manufacture of Pb - acid
battery container. Process is raw material dehumidification, charging into screw barrel cylindrical heat
chamber and finally moulding. This section has capacity of 660 T/ 19 machines. Product rejection is
1.5 – 2 % which are also reused.
2. Preparation of MS box container from MS sheet
Mild Steel (MS) containers of the battery are manufactured at the unit from MS Sheet using semi
-automatic welding machines. Production capacity is 40 nos.containers/hr.
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10. 3. Powder coating division for MS container
Stages are as follows -
i) Degreasing – by Meta Clean ( a biodegradable surfactant) at a temp. of 70-800 C and
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residence time of 10-15 min.
ii) Water rinse – Process pH is 7-9 at ambient temp. with residence time 1-2 min.
iii) De rusting - by Phosphoric acid at ambient temp. having residence time 5-10 min.
iv) Water rinsing - Process pH is 5-7 at ambient temp. with residence time 1-2 min.
v) Activation – by Refine 2/2 at pH 8.5-10, and at ambient temp. with residence time 1-2 min.
vi) Phosphating – by zinc tri phosphate( Phosband 511T) at a temp. of 50 -550 C and residence
time of 5-10 min.
vii) Water rinsing – by DM water at pH 5-7, and at ambient temp. with residence time 1-2 min.
viii) Passivation – by acidic liquid chemical (Passtreat) at pH of 4-5 and at a temp. of 65-750 C
and residence time of 1-2 min.
ix) Dry off oven
x) Powder coating into an enclosed chamber where APC device is multicyclone .
xi) Curing oven – temp is 2000 C.
4.
Battery assembling unit
The Steps are -
i) Pb plates are used as (+) ve and (-) ve electrodes. In between separators are applied.
ii) Charging points are welded on to lead plate by LPG welding.
iii) Plate assembly are welded by automatic squeeze welding.
iv) Plate assembly are kept within plastic container and heat sealing is applied.
v) Leak testing of container is done.
vi) Electrolyte (sulphuric acid) filling for cell formation. To control cell temp. batteries are
dipped into water bath for 96 hrs.
vii) Automatic gel filling into battery in acid : silica gel proportion of 10 : 1.
viii) Charging, discharging and capacity testing – 120 batches are charged at a time as one batch
contains 20 batteries.
5. Metal recycling section
HBL has its own used battery recycling division. Initially, manual separation of plastic and Pb metal
are done from the waste batteries. Then the metal part is sent to smelting and refining section.
a) Smelting section -
The unit has 3 nos. F. O. fired rotary furnace. Each has capacity of 1 batch / day. 1 batch is 5 T metal.
1 batch takes 7 -8 hrs. In furnace, scrap metal with charcoal are charged through front manhole.

11. Product is taken out through bottom manhole. Fumes coming out from the furnace enters into settling
chamber, heat exchanger, cyclone separator, bag house and then stack of height of 30 m from G L.
b) Alloying section -
Unit has 4 nos. F. O. fired vertical refining melting pot. Each pot has capacity of 10 T/batch. Each
batch takes 24 hrs. Top fumes are drawn into water scrubber, ID fan and finally stack of height 30 m
from GL.
6. Pb sub oxide
Molten Pb at 4500 C is pumped into top covered vessel fitted with agitator. Product is collected from
cyclone, and bag house with the help of ID fan.
7. Red lead unit
Unit has 2 nos. red lead furnaces. Lead sub oxide powder is charged into HSD fired brick lined
furnace fitted with agitator. The furnaces are provided with water scrubber, ID fan and finally stack of
height 30 m from GL.
8. Effluent Treatment Plant
Effluent is generated from acid, acid- gel filling , cell formation, gel preparation, acid preparation,
floor washing activities. The unit has installed a full-fledged effluent treatment plant alongwith
R.O.Plant. The treated water from the R.O. Plant is reused.
The ETP consists of the following components:
i) Grit Chamber
ii) Holding tank
iii) Settling tank
iv) Neutralization tank
v) Stabilization tank
vi) Sand and activated carbon column filter
vii) R.O. Plant – 13 KLD water which is recycled and RO reject is sent to double effect
evaporator system.
viii) Double Effect Evaporator – produces 12 KLD condensate which is cooled and reused
as process water. Concentrate from DEE is 1 KLD which is treated as hazardous waste.
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12. D. Cleaner Technology adopted at HBL Power Systems Ltd.
a) VRLA (Valve Regulated Lead Acid) Battery :
The Valve Regulated Lead Acid (VRLA) battery is one of many types of lead -acid batteries. In a
VRLA battery the hydrogen and oxygen produced in the cells largely recombine back into water.
In this way there is minimal leakage, though some electrolyte still escapes if the recombination
cannot keep up with gas evolution. Since VRLA batteries do not require regular checking of the
electrolyte level, they have been called Maintenance Free (MF) batteries. However, VRLA cells do
require maintenance. As electrolyte is lost, VRLA cells may experience "dry-out" and lose
capacity. This can be detected by taking regular internal resistance, conductance or impedance
measurements of cells. This type of testing should be conducted on a regular basis, as an indicator
that more involved testing and maintenance may be required. Recent maintenance procedures have
been developed allowing "rehydration" of cells that have experienced dry -out, often restoring
significant amounts of the lost capacity.
VRLA types became popular on motorcycles since about 1983, because the acid electrolyte is
absorbed into the medium which separates the plates, so it cannot spill. This medium also lends
support to the plates which helps them better to withstand vibration. They are also popular in
stationary applications, such as telecommunication sites, due to their small footprint and flexibility
of installation. The electrical characteristics of VRLA batteries differ somewhat from wet -cell
lead-acid batteries, and caution should be exercised in charging and discharging them.
The VRLA battery is by far the most popular reserve power design because the electrolyte is
captive preventing it from spilling even when the case is punctured. VRLA batteries are considered
“maintenance free” & require no addition of electrolyte or water. The valve regulated lead -acid
battery is designed by development of the grid design, by modifications to the materials used in
battery manufacture and the incorporation of a sophisticated but low-cost battery management
system.
HBL now offers a VRLA tubular grid gel-type battery well tailored for applications which
require a small foot print. Gel technology affords higher operating temperatures, deeper
discharges with recharges that do not unnecessarily compromise battery service life. This battery is
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13. designed for microwave transmission towers, wireless/cellular huts, satellite receiver stations, fibre
optic transmission systems, radio repeater and base stations and other applications. HBL employs a
vacuum impregnation fill technology that eliminates air gaps, voids and inclusions prevalent in
many other gel and hybrid gel batteries. This makes a “true gel” product as opposed to a standard
VRLA battery with merely a layer of gelled electrolyte “spread” across the top of the jar casing.
The tubular gel series is well tolerant of deep discharge and partial state of charge (PSOC) cyclic
operations.
11
Benefits of these batteries are as follows :
Does not require water top-up throughout its life
No corrosive fumes and hence no special battery rooms are required
Stackable design minimizes space requirements
Designed for high integrity long life
Application specific designs
Customized layouts for optimum space utilization
Safe-Explosion proof, leak-proof flame-retardant materials
Consistent performance over life time
Improved aesthetics
Easy installation
Typical applications are telecommunications, switch gear, process control systems, railway signalling
communication and renewable energy.
b) Jar Formation of Battery Plates :
Battery plates undergo an electrical formation in two ways – Tank formation and Jar formation.
Tank formation is the traditional process of battery plate formation before assembly. In this method ,
cured pasted plates are loaded into large baths of dilute sulphuric acid and a direct current is passed to
form the positive and negative plates. After formation, plates need to be thoroughly washed, dried
followed by cutting and then assembled with separators between them into the battery boxes. Plates of
like polarity are connected by welding the plate lugs. At the end of formation, acid specific gravity (sp. gr.) goes up as
per the following electrochemical reaction (based upon the inherent sulfate content in the plates and
acid quantity in the tank).
Positive plate : PbSO4 + 2H2O = PbO2 + H2SO4 + 2e- + 2H+
Negative plate : PbSO4 + 2e- + 2H+ = Pb + H2SO4
After the plates are taken out from the tanks, some quantity of acid needs to be discharged (around
40 lit. of acid with sp. gr. 1.080/tank) followed by dilution with water to bring the sp. gr. of the acid
back to original value before the next lot of plates are loaded. Discharged acid becomes part of
effluent.
In the modern manufacturing process this tank formation is replaced by jar formation, whereby
batteries are assembled using unformed plates followed by in-situ formation of plates in the battery
itself.

14. In the jar formation process, batteries are filled with acid of sp. gr. adjusted in a way so that after
formation the sp. gr. goes up to the final sp. gr. required in the product. Hence no acid needs to be
discharged. Moreover, there is no requirement of plate washing. Thus, generation of acid effluent is
significantly lower than tank formation. Moreover, due to less no. of operation and thereby handling,
scrap generation and leady effluent generation is also less.
From pollution point of view, the jar formation process has some significant advantage over tank
formation route as listed in the table below.
ADVANTAGES OF JAR FORMATION OVER TANK FORMATION
Tank formation route Jar formation route
No. of operations in
plate processing
More Less
Discharge of excess
acid from forming tanks
after every formation
cycle
Sulphuric acid with sp. gr.
1.080/circuit to be discharged every
day. (Acid content-12%)
No discharge of acid
Cleaning of tanks
(approx. after every 1
month)
Discharge of acid with sp. gr.
1.080/circuit-once in a month
Discharge of lead oxide sludge
(~176kg/circuit) from the forming
tanks -once in a month
Discharge of acidic water from
water bath (acid content 1%) to
maintain pH above 2.
Washing of plates Both negative positive plates need
to be thoroughly washed leading to
generation of acid and lead particles
contaminated effluent.
No such washing of plates
required.
Overall effluent
generation (acidic
leady)
High No leady effluent generation.
Acidic effluent generation is 1/4th
in JF compared to that in tank
formation route.
Generation of acid
fumes
Significant at finishing stage from
the large open surface
Less through use of mist
eliminator in the vent hole of the
batteries
Removal of acid fumes By passing through alkali scrubber By passing through alkali scrubber
Subsequent operation
in the field
Acid filling followed by charging at
dealer's end.
Does not require any acid
handling as well as charging at
dealer's end.
From the customer's angle the jar formation route gives following benefit :
batteries are available ready to use
Control in acid quality and proper charging
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15. c) Steps taken to reduce lead scrap generation :
Stage wise Scrap Reduction Methods
Sl. No. Section Methods for Reduction of Scrap
1 Plate shop
a) Pasting Automated paste mixing system for reduced manual
handlings for reduction of lead powder spillages.
b) Curing Drying Usage of bigger chambers and better handling systems like
fork trucks model specific skids.
2 Cell Assembly Automated cell assembly lines for minimising process
rejections
3 Formation Programmable charger cum dischargers and datalogging
systems for minimising manual errors and improved
product quality.
4 Battery Assembly
Packing
Better handling systems like pallet trucks, diesel fork
trucks, battery operated trucks EOT cranes.
5 Dispatch Better handling systems like pallet trucks, diesel fork
trucks, battery operated trucks EOT cranes.
Apart from these t raining of manpower, preventive maintenance schedules and ISO systems which
are common as a part of TQM.
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d) Automatic Electrolyte Filling :
HBL Power Systems Ltd. has adopted automatic vacuum impregnation electrolyte filling technology.
In this process, the electrolyte is filled into the cells under vacuum condition and so the chance of
spillage of acid/electrolyte in the working area is reduced to a great extent.
e) Reverse Osmosis Plant in the ETP :
The industry has installed R.O. plant in its effluent treatment section. The treated water from the
R.O. plant is reused. This reduces the chance of water pollution as well as conserves the underground
water.

16. The main source of pollution is the emission from the lead smelting furnace. In West Bengal,
all the secondary lead smelting units are small scale and use old vatti type pit furnace. Another
major pollution source is the lead bearing slag which is a hazardous waste.
14
E. Secondary Lead Smelting :
With the increasing demand of batteries, generation of lead scrap/waste is also increasing day by day.
The lead wastes/scraps need to be handled very carefully to protect the environment from pollution.
The best way to handle this hazardous substance is to recycle the material. Recycling is the key
component of modern waste reduction methodology. Recycling involves processing of the used
materials into new products to prevent wastage of potentially useful materials, to reduce the
consumption of fresh materials, to reduce energy usage and also to reduce environmental pollution.
About 50% of the lead used in various applications is recovered from the secondary lead smelters.
1. Brief Manufacturing Process :
Smelting is a thermal metallurgical processing operation in which the metal is separated in
fused form from non-metallic materials or other undesired metals with which it is associated.
The main steps involved in secondary lead smelting activity are smelting of the lead bearing
wastes after addition of fuel and flux, cooling and casting of molten lead into lead ingots.
Usually, charcoal is put in the furnace and it is ignited by blowing air. Then charcoal is
fed further to fill the furnace chamber. The lead scraps/wastes and charcoal are then fed
alternately at definite proportions depending upon the raw material quality. Molten lead is first
tapped after a definite time period and made into lead ingots by pouring into moulds. Usually,
lead content in battery scrap is 75-80%. In the first charge about 40-50% of lead comes out and
the slag contains the balance lead. This slag is further charged in the furnace for melting for 3-4
times for extraction of lead. Resid ual slag contains about 2% of lead and is disposed as
hazardous solid waste.
2. Sources of Pollution :
3. Pollution Control Systems:
The general method of arresting the dust particles in the flue gas coming out from the furnace
is to install a cyclone separator, bag filter and then a scrubber. The lead bearing solid wastes are
stored in safe and environment friendly manner and finally disposed to engineered landfill.

17. F. Conclusion Way Forward :
According to a 2003 report entitled, Getting the Lead Out, by Environmental Defense and the
Ecology Center of Ann Arbor, Mich., an estimated 2.6 million metric tons of lead can be found in
the batteries of vehicles on the road today. There is little argument that lead is extremely toxic.
Scientific studies show that long-term exposure to even tiny amounts of lead can cause brain and
kidney damage, hearing impairment, and learning problems in children. The auto industry uses
over one million metric tons of lead every year, with 90% going to conventional lead -acid vehicle
batteries. While lead recycling is a mature industry, it's impossible to rescue every car battery from
the dump. More than 40,000 metric tons of lead is lost to landfills every year.
Lead-acid battery recycling is one of the most successful recycling programs in the world. In the
United States 97% of all battery lead was recycled between 1997 and 2001. An effective pollution
control system is a necessity to prevent lead emission. Continuous improvement in battery
recycling plants and furnace designs is required to keep pace with emission standards for lead
smelters. Also, proper collection of used batteries and extraction of lead through environment -
friendly secondary lead smelting technology like use of rotary furnace/ reverberatory furnace in
place of old vatti type furnace need to be practised to minimize the scope of environmental
pollution.
In West Bengal, apart from Exide Industries Ltd., mostly lead acid batteries are manufactured in
small scale sector and these are located in clusters in some areas. Adoption of modern
technologies/automation in battery manufacturing and charging will certainly reduce the risk of
environmental pollution/degradation but it is a challenging task for the tiny scale units. ECAC may
take up a demonstration project in one such cluster of small scale lead acid battery manufacturing
units in this regard.
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18. 16

19. Gel filling section Gel filling section
Automatic gel filling of battery Automatic gel filling of battery
Automatic gel filling section at M/s HBL, Meheboob Nagar, Hyderabad
17

20. F. O. fired rotary furnace for lead smelting Vertical alloy making furnace(F.O. fired)
Cyclone separator connected to F.O. fired
rotary furnace of lead smelting section
Bag house connected to F.O. fired rotary
furnace of lead smelting section
Wet scrubber connected to F. O. fired melting
pot for alloy making
Wet scrubber connected to F. O. fired
melting pot for alloy making
Furnaces and APC devices of smelting and alloying section at M/s HBL, Meheboob Nagar,
Hyderabad
18

21. Battery breaking section Battery breaking section for separation of
lead and plastic from used batteries
Battery breaking section
Lead strips preparation section at M/s HBL, Meheboob Nagar, Hyderabad
19

22. Bag house for product collection of red lead
section as APC device
Cyclone separator for product collection of
red lead section
Lead sub oxide and red lead manufacturing units at M/s HBL, Mehboob Nagar, Hyderabad
20

23. Flow Diagram of the ETP Flow Meter at the intake point
Inlet to collection tank Collection tank
Used acid gel mixture during filling within
battery stored within vats at ETP for treatment
pH adjustment and equalization tank
Effluent Treatment Plant at M/s HBL, Meheboob Nagar, Hyderabad
21

24. Cake preparation at filter press after lime dosing
for pH adjustment
R. O. section
R. O. section
Lead oxide paste preparation Lead oxide paste preparation
22

25. Different sections for lead oxide pasting onto strips at M/s HBL, Meheboob Nagar,
Hyderabad
23

26. Plastic moulding division of M/s. HBL, Mehboob Nagar Plant, Hyderabad
24