Established in 1942
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Since 1942 Strommasina Corp. has been successfully producing equipment for the mining, building, oil and gas, as well as road, metallurgical industries.

Starting of a lime production plant with capacity of 70,000 tons per year

Lime is a common name of products produced from limestone. In terms of application, there are process and building lime types. The former is used in different production processes: in metallurgy, chemical and food industries (it is added to sugar, decontaminating agents, paper, cellulose). Building lime is used for limewhiting of buildings, production of lime whitewashes and building mixtures. Ground limestone and lime powder are added to mixtures for asphalt concrete, to compound feed, fertilizers. Different types of slaked lime are used for preparation of fertilizers, chloride lime and for leather working.
In terms of the content of calcium silicates and alumoferrites in lime the latter is classified as:

  • hydraulic lime. It contains clay and is hardened when exposed to water. It is used for preparation of cement grouts used for brick laying, etc.
  • air-hardening line is a product consisting of limestone mainly. It hardens in air-dry medium.

In terms of size distribution lime is divided into lump and powder lime.
In terms of the further processing method air-slaked lime is divided into freshly burnt non-slaked lime and slaked lime. The latter may be of different types, depending on the quantity of added water:

  • hydrated lime – fine powder with low water content;
  • lime milk (30 to 40% of free water);
  • lime paste (80 % of water).

The Strommashina plant has vast experience in designing and manufacturing the lime production equipment of any types. We offer the full range of equipment for starting profitable and fast-payback lime production business. Using our lime milk and lime paste production process lines, and lime production line will allow you obtaining high capacity at minimum maintenance and repair costs. The industrial equipment of Strommashina brand can be operated for several decades and has won international recognition as very reliable and cost efficient long time ago.
The lime production process is not considered to be complex, and demand for lime will be sustained as long as buildings and roads are built and repaired.

Lime production process

Different sedimentary rocks are used as the raw material: limestones (marble, dense fine, oolite), chalk, dolomites. Dense limestones are used most commonly.
The lime production includes several stages. First the raw material (0 to 300 mm particle size) is fed the the receiving bin of the plate feeder which delivers it to the crusher. After preliminary chipping the belt conveyor transports the raw material to the oscillation screen where the limestone is sorted based on particle size: 5 to 20 mm, 20 to 40 mm, and less than 5 mm. Fine fraction raw material (less than 5 mm) is fed for processing to ground limestone. The coarse fraction lime is fed to the bin where the raw material is weighed. Then the mixture of lime and fuel is heated and fed to kiln for calcining. Rotary kilns or shaft kilns equipped with coolers are used usually.
Specifications of such a kiln are: diameter – 2 to 3 m, length – 5 m, capacity depends on the fuel: coal – 30, 50, 100 and 200 t per day, natural gas – 200 t per day, fuel oil residue – 150 t per day. For rotary kiln the fuel oil residue and gas are used as a fuel. Specifications: length – 30 to 100 m, diameter – 1.8 to 3 m, capacity – 15 to 40 tons per hour. Now, due to some advantages, gas- and coal-fuelled shaft kilns are used most frequently (they are easy to use and consume little fuel; they are the cheapest kilns).
After calcining in the kiln the lime is cooled in cooling equipment from 1000 to 100–130° С. The resulting product is non-slaked lump lime which is subjected to further processing in two ways: it is ground in mills – the resulting product is non-slaked ground lime, it is slaked in water – the resulting product is slaked lime.
Lime is slaked using different methods. The batch hydrator or continuous hydrator are used to produce the slaked lime. The lime chipped to 3–5 mm is charged into the drum and slaked with steam. The slaking and discharging process takes 30–40 minutes. Lime is charged into the bin for ageing where it continues to be slaked which improves the product quality.
The method of slaking to paste is used seldom due to to the process complexity. The non-slaked lime is chipped to 5 cm lumps and is slaked in the bin for about 2 hours. The final slaking with water heated to 40–50 C is carried out in the slaker. The lime milk is screened at the vibratory screen: coarse particles are separated. Then the lime milk is fed into tanks where it is settled. Any excess of water is drained through filters, the resulting product is thick creamy thick product.

The approximate configuration of the lime production line:

Preparation room
- vibratory feeder
- jaw crusher
- belt conveyor
- bag filter
- rotary valve
- screw conveyor
- chain elevator
- screening plant
- belt conveyor
- silo
- plate feeder
- batch bin
- belt conveyor
- chain elevator
- intermediate bin
- pressure filter

Calcining room
- chalk heater with chain drum drives
- rotary kiln
- cyclone
- flue-gas fan
- gas burner
- drum cooler
- cyclone
- flue-gas fan
- screw conveyor

Finished products storage area
- belt conveyor
- chain elevator
- finished product silo

Room and personnel for maintenance of the lime production equipment

The limestone production plant can be divided into the following departments:

  • crushing section;
  • raw material mill section;
  • mixing and storage section;
  • vertical shaft kiln section;
  • mill section;
  • storage and packing section;

The room area is about 2000 sq. m (rent is about 300 thous. roubles per month)
Power consumption per one ton of the product is about 115–125 kW/h.

The following personnel will be required for organization of the plant producing 50 tons of non-slaked lime per day:

Crushing room:
- crusher operator;
- conveyor motor man;
- elevator motor man;

Screening room
- screen motor man;
- motor man mate;
- conveyor motor man;
- elevator motor man;

Calcining and cooling room
- shaft kiln burner;
- conveyor motor man;
- shaft kiln motor man mate;
- elevator motor man;
- pump man;
- aspirator man;
- conveyor operator;

Auxiliary personnel:
- operator;
- shift fitter;
- shift electrician;
- lab assistant;
- cleaners;

Taking into consideration the administrative personnel of the plant (managers, accountant), the total headcount will amount about 24 people. The payroll per month is about 600 thous. roubles.

Requirements to lime storage and transportation

According to GOST 9179-77, lump lime is shipped in bulk, powdered lime is shipped in bulk or in paper bags according to GOST 2226. With the consumer's consent it is admissible to use four-layer paper bags. Lime is transported in roofed transport of any type. Different lime types should be stored and transported separately without any exposure to moisture or contamination by foreign substances. The guaranteed storage life is 30 days from the date of its shipment to the consumer. Non-slaked lime preserves its properties for 15 to 18 days if it is stored properly.

Safety requirements to lime production process systems

The lime production is hazardous, so some rules should be observed. First, the calcining kiln should be operated carefully as it may be the cause of production ignition or burn injury. One should keep clear of the kiln sight cap. Carbon oxide, carbon dioxide may cause poisoning, so the raw material is only charged on special containers, these substances shall be prevented from penetration to personnel facilities. The lime dust is hazardous to mucus membranes and wet skin. To eliminate any dusting, the transport and bins shall be covered with casings, caps, de-dusting devices shall be installed and hydraulic suppression of dust shall be applied. The belt conveyors shall be equipped with canopies all over their length. They shall move at speed no more than 1 m/s. The operators shall wear face masks and special clothes.

Investments and payback of the lime production line

For the capacity of 50 tons of lime per day the initial investment would amount about 6 to 7 mln. roubles. The monthly costs will amount about 1.8 mln. roubles. The product price (for reference only): non-slaked lime – 2 029 roubles/t, slaked lime – 3 237 roubles/t. The monthly profit is about 600 to 800 thous. roubles. The business will pay back in 8 to 12 months.
The lime production unit manufactured by Strommashina plant can ensure much higher capacity –  up to 200 tons of lime per day or 70,000 tons of lime per year.

Demand and the main consumers

For sales of a new product one should know its main consumers.  In this case they are: construction industry enterprises (producers of silicate concrete and cell concrete, dry construction mixtures), municipal services and waste processing (specifically, gas conditioning and water purification).

Generally, the plant which need lime produce it themselves. Thus, it is not expedient to organise production with large share of such lime type, although it accounts for 85 % of the market. According to research, the share of non-slaked lime in the structure of the construction lime production in Russian Federation in December, 2015 was 93.1 % which means high demand for this product.

Specialists of the Strommashina plant will readily give exhaustive answers to any questions concerning lime production. Using our equipment, dozens of enterprises have progressed from a start-up to a successful business. We are ready to provide our clients with all necessary assistance and supply our high-quality equipment with excellent maintenance.

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