Category Archives: Road construction industry

Colloid Mill for Bitumen Emulsion Production

Bitumen Emulsion Production

Bitumen Emulsion Production. A colloid mill is a special device which performs superfine pulverization of materials. Using colloid mill allows to produce particles of one micron or even smaller.

The first colloid mill was designed by K. Plausson in the first half of the 19th century. It consisted of a stator, a rotor and a body. When particles enter the gap between the rotor and the stator, they rotate rapidly, and the centrifugal force tears the particles apart. The grade of pulverization can be adjusted by changing the gap between the rotor and the stator.

GlobeCore has developed colloid mills to be used in production of bitumen emulsions. They can produce both regular bitumen emulsions and emulsions modified by polymer.

The interaction between the rotor and the stator is optimized so that the size distribution range of the pulverized bitumen particles is narrow. This allows to make stable bitumen emulsion with high viscosity, which is especially important in production of high bitumen content emulsion.

The CLM colloid mill allows to disperse and homogenize bitumen at the same time. A heating jacket is provided to apply heat in the pulverization area.

GlobeCore colloid mills feature high rate of processing and pulverize bitumen to 1 micron particles. The CLM mill can be retrofitted easily into existing bitumen emulsion and modified bitumen production lines.

For high quality of grinding, it is necessary to supply the raw material at a certain proportion of solid and liquid phase at constant rate.

Another advantage of GlobeCore equipment is the ability to adjust the grade of pulverization and the pumping performance.

About functions and methods of the bitumen emulsions: block the aqueous phase

block the aqueous phase

Different types of bituminous emulsions are mostly used in the construction industry. The main areas of application are following:

  • priming of old pavement before applying asphalt;
  • preparation of cold asphalt mixtures;
  • surface treatment of road surfaces;
  • thin protective layers;
  • patching roads;
  • waterproofing of structures;
  • installation and repair of soft roofs.

The main advantage of bitumen emulsions in comparison with conventional bitumen (or resin) is their use in higher humidity, lower ambient temperature and lower consumption of bitumen.

Due to the fact that the bitumen emulsions have significantly lower viscosity as compared with ordinary bitumen, heating of emulsions and mixes is not required.

Besides, bitumen emulsions allow operation in adverse weather conditions. The use of hot bituminous mix even with the addition of a surfactant do not offer the necessary quality.

With such a wide range of benefits, bitumen emulsions are increasingly popular. This makes it viable to acquire a plant for production of bitumen emulsions, mixing bitumen with water and the various additives necessary for production of the product according to the formulation, reflecting the facility’s requirements.

The UVB-1 bitumen emulsion unit is a semi-automatic system, which consists of several individual modules installed on the same frame: emulsion preparation and water phase preparation units, as well as the control panel.

Production of bitumen emulsions usually involves two stages: preparation of water phase and emulsion preparation.

Water phase is a water solution of the emulsifier, the agent for the transition of the emulsifier into ionic form (acidic reagents for cationic emulsions and alkaline substances for anionic ones) or other components necessary to improve the emulsion.

The water phase unit is equipped with piping, including visual flow indicators, valves and instruments.

Water phase is prepared in tanks with agitators, according to the formulation: volume, temperature, pH and dosage of the components are all controlled. The water phase and hot bitumen are supplied to the colloid mill for mixing. If necessary, bitumen can be thinned by controlled injection of a thinner liquid into the bitumen pipeline.

Portioning the components of the water phase and the thinner is automatic, by the pumps which supply the substances into the pipelines for continuous emulsion production.

Vertical pumps of various models are installed for the supply of water and blend.

The thinner is supplied by a gear pump.

Actual flow is of components is controlled by flow meters with varying measurement ranges: up to 10 m3/h for water, up to 4 m3/h for blend and up to 0.25 m3/hour for thinner.

A great deal of world known technologies in civil and industrial construction use complex bitumen emulsions prepared according to custom formulations. Recently, modern systems for production of high-quality bitumen mixtures and emulsions are becoming increasingly common in the domestic market.

Research and experiments reveal brand new models and formulations to achieve an even greater effect in the use of bitumen emulsions.

Dispersed Systems and Equipment for Dispersion

Most substances used in households and industry are dispersed systems (solid particles or droplets suspended throughout another substance) or solutions, where mixing takes place at the molecular level. Examples of suspensions are mortar mixture, paint, white glue or bitumen emulsion used for waterproofing works.

What is bitumen emulsion?

Bitumen is a hydrocarbon resin (derived from petroleum) which solidifies in the air at normal temperatures, forming a watertight flexible film. The mixture of bitumen with sand and gravel is used for roadworks (known as asphalt). Aqueous bitumen emulsion is widely used for waterproofing foundations, roofs and sealing joints between concrete blocks in construction.

Types of bitumen emulsion and production formulas

Emulsions are divided by two parameters

  • Settling rate (water separation, forming of bituminous film):

– rapid setting: immediately within 5 minutes of application;

– middle setting: within 5-10 minutes when applied on rubble, concrete, etc;

– slow setting: more than 10 minutes, also known as “ultra stable”;

  • type of emulsifier added to stabilize the emulsion: anionic (alkali salt) and cationic (acid soap). Emulsifier solution for bitumen emulsions are prepared directly before heating and mixing water with bitumen.

Preparation and dispensing of bitumen emulsion

The primary methods used for production of disperse systems are mechanical and acoustic. In the mechanical process  the emulsion is formed by mixing bitumen and water solution by a rotor rotating 0.2-0.6 mm from a stator. These machines are known as colloid mills and are divided into two types:

  • batch mixers, where bitumen and emulsifier are fed into a dispensing mechanism first, then heated and mixed;
  • continuous mixers (dispersers), rotary or plunger. Water and emulsifier components connect in a flow line, where they chemically react with acid. The colloid mill processes the solution and heated bitumen that are mixed into the finished product. After cooling down, the bitumen emulsion is dispensed into containers.

Advantages of dispersers:

  • continuous operation (until the flow of raw materials stops);
  • high productivity without dispensing devices and additional pumps for them;
  • ability to quickly switch from one emulsion to another.

Bitumen Emulsions for Road Construction

The main objective of laying asphalt concrete mixtures as a road surface is to ensure its adhesion to the bottom layer.  A practical solution to this problem is -using bitumen emulsions.

Bitumen emulsion disperse system consists of: bitumen and water.  Thus the smallest particles of bitumen are dispersed in water without being mixed with it.

According to the type of emulsifier, all emulsions are divided into two types: cationic and anionic.  Road builders primarily use cationic bitumen emulsions, as their disintegration occurs chemically.  The disintegration of anionic bitumen emulsions is achieved by evaporation of water.

Bitumen emulsions are divided into EBC (Effective Binder Content) types:

  • quick-setting emulsion (EBC-1);
  • medium-setting (EBC-2);
  • slow-setting(EBC-3).

Each of these types has its own field of application: EBC-1 and EBC-2 – the roads construction, and EBC-3 – pothole repair.

Another important technical indicator for EBC-1 and EBC-2 is – viscosity. When viscosity is low, emulsion is not thick enough and will flow down from higher areas and accumulate in lower areas.  This phenomenon results in uneven adhesion between layers and further pavement deformations during exploitation.

In case of too high viscosity, the strips will appear instead of integral and uniform coating, which also contributes to bad adhesion between the layers.

Viscosity of bitumen is determined by penetrometer – a compact instrument with a needle.  The viscosity limit is measured according to the depth of needle penetration.  Penetrometer is not suitable for bitumen emulsion because their density is close to the density of water.  Therefore, to evaluate the relative viscosity of bitumen emulsion, a viscometer is used.

Relative viscosity depends on granulometric structure : grain concentration and grain size of the material.  It can be  adjusted  using a colloid mill, designed for dispersing bitumen in water medium.  By changing the size of the gap  between a rotor and a stator of the colloid mill – achieves the change in granulometric structure.

Also relative viscosity may be affected by emulsifier (it’s type and amount).

GlobeCore bitumen emulsion plants are:

  • UVB-1 with capacity of 1 m3/h;
  • UVB-1 with capacity of 2 m3/h;
  • UVB-1 with capacity of 8 m3/h.

Modified bitumen emulsions and production equipment

Bitumen is a unique blend of hydrocarbons and their derivatives that are widely used in construction, from residential and industrial structures to highways and runways.  While bitumen can be replaced with materials of similar composition, replacing it with something of similar cost is virtually impossible.  Bitumen has been used in construction for centuries.  During this time, due to its excellent binding abilities, builders have come to greatly appreciate bitumen’s qualities.  These qualities are defined by the crude oil used to make bitumen and the method and quality of the oil refining process.

Modern petrochemical industry professionals attempt to maximize the yield of light oil products and extract most of the paraffin-naphthenic fractions from the bitumen.  This reduces its flexibility at low temperatures and reduces the softening point at high temperatures.  Most modern bitumen will lose elasticity at approximately twenty degrees (20oC) and begin to soften at between +45oC to 48oС.  The use of non-modified bitumen therefore, in both road construction, which requires a binder with a temperature range from -40oC to +70oC, and for roofing materials, which are often subjected to temperatures up to 90oC, is not efficient.  Fortunately, there are ways to change and improve the properties of bitumen by mixing it with various additives.  This is best achieved in special bitumen modification units such as the GlobeCore UVB bitumen modification system.

The least expensive method of improving bitumen’s useful temperature range is to add a large amount (15% or more) of mineral filler such as chalk or talc.  The result is a very thick product mostly used as a mastic.

It is far more popular to modify bitumen using byproducts of other processes, such as rubber pellets from used tire processing or rubber resin ataxic foam propylene.  Unfortunately, the technology of mixing such filler with bitumen requires temperatures above 180oC.  Such high temperatures will disintegrate the structure of the rubber resin and oxidize the bitumen.  The result is a modified bitumen with a high softening point, but with low ductility, elasticity and high brittleness at low temperatures.  This makes it difficult to use in road construction.  The alternative to high heat is to introduce more components (swelling accelerators, plasticizers, and adhesives), thus significantly increasing the cost of the modified bitumen.

A better solution is found in a separate group of modifiers known as polymer additives.  They include ethyl vinyl acetate and its graft copolymers, as well as high and low pressure polyethylene.  These additives are more convenient to use than mineral ones.  They significantly increase the useful temperature range especially at the high side of the range without increasing the brittleness characteristics of the bitumen.

Polymer modified bitumen has been used with great success as a sealant or mastic in roof construction and waterproofing, but its use in road construction is limited by to temperatures above -15oC which reduces it use warm seasons and very mild winters.

The most widely used bitumen modifiers today are the so called “styrene rubbers” such as styrene-butadiene-styrene (SBS) and styrene-ethylene-butylene-styrene (SEBS).  These additives improve the elasticity of bitumen at all temperatures and provide high ductility.  The “Brittle Point” drops to -24oС, making bitumen modified with SBS and SEBS useful in road construction and repair even during cold winter months.

Introduction of small amounts of other additives, such as polymeric petroleum resins, improves surfactant properties of modified bitumen for the production of excellent primers, mastics, and gluing compounds.  The use of polymeric petroleum resins as a primary modifier increases hardness of bitumen and its softening point.

If you are in the market for bitumen modification equipment, we recommend that you contact GlobeCore’s specialists.  The GlobeCore UVB units incorporate versatile assemblies for preparation of various types of modified bitumen.  The units include two reactors with vane agitators, colloid mills, heaters and precise portioning systems for both bitumen and modifiers. These bitumen modification units produce excellent bitumen products based on any modifier and additive, thereby giving your products a wide and stable market.

Colloid Mills for Water Bitumen Emulsion Production

Water-bitumen emulsion is highly appreciated by building and road construction companies.  This is due to  its ease and safety of use  in comparison with the mixtures based on solvents of and from petroleum products such as kerosene.  As a rule, water-bitumen emulsion is obtained by blending liquid bitumen with water  and special emulsifiers and acids.

Having years of experience in designing and building blending machines and bitumen emulsion units, GlоbeCоre is one of the most reliable manufacturers of modern equipment for production of water-bitumen emulsions anywhere in the wolrd today.

A colloid mill is considered to be the heart of any bitumen emulsion production equipment where bitumen is grinded into  small droplets and is then evenly distributed in water.  In the past, manufacturers of equipment used blending equipment such as dispergators and ultrasonic homogenise that perform the wet grinding of the dispersed  phase of bitumen production.

GlоbeCоre Colloid mills for wet grinding can produce highly-stable dispersed systems from two or more  mutually insoluble  substances.  Bitumen emulsion units (depending on the desired size of bitumen droplets) use three groups of colloid mills.

The first group of colloid mills provides 90% of droplets with a size of less than 5 microns (a minimum size of a droplet of 1-2 micron).  They are used  to manufacture polymer-modified emulsions, bitumen emulsions for surface treatment ( “chip seal”), recycling, soil stabilization, grouting, tack coating and similar technological processes.

The second group of colloid mills provides 90% of droplets at the outlet with the size of less than 10 microns (a minimum size of a droplet of 4-5 micron).  The areas of its application include: simple slurry mixtures, surface treatment, tack coting, recycling, and grouting.

The third group of colloid mills produces bitumen emulsions with a minimal size of a droplet of more than 5 microns (no more than 10% of droplets are larger than 10 microns).  Such bitumen emulsions are used  for surface treatment, tack coating and grouting.

Since colloid mills are mostly mounted in line with continuous blending units, components are supplied directly to the unit.  As a rule, the water phase is prepared in advance to withstand the required temperature, PH level and emulsifier metering.  Then the water phase and warmed-up bitumen are supplied to the input of the colloid mill to be  dispersed.  If necessary, the viscosity of bitumen is reduced by injecting  flux  to the feed line.

The ratio of components is maintained automatically by metering pumps in accordance with the program or by temperature control of the source components, by measuring the temperature of bitumen emulsion at the outlet (as a rule it is 85-94°С)  and  the subsequent flow adjustment.

If required (depending on the formula), the colloid mill may be supplied with latex that allows for modified bitumen emulsion production.  At the outlet of a colloid mill, there is a three-way valve that provides recycling of water solution of emulsifier, mill flushing or discharge of the finished bitumen emulsion product.

GlobeCores continuous bitumen emulsion equipment has a wide range of benefits that include; (1) a rapid change of the type of emulsion produced; (2) no impact of reagents on the staff; and (3) low operating costs.

Bitumen Emulsion Production Units

UVB-8

As a rule, bitumen emulsion is made by colloid mills, but many industries apply other units that allow for dispersion.  In colloid mills, the mixture of hot bitumen and water phase are passed between a rotor in full motion and a stationary stator.  There are special claws and slots on the surface of the rotor and stator that provide for turbulent flow.  There may be batch and continuous bitumen emulsion units.

Batch units require two production stages to be performed:  (1) water-phase preparation; and (2)  production of bitumen emulsion phase.  The water phase is prepared in a special container with the metered components added.  The resulting solution should be thoroughly blended.  At the next stage, the bitumen and previously prepared water phase are supplied to the colloid mill.  Precise metering of components is essential to obtain a high-quality bitumen emulsion.  Production units with semi-automated and automated controls help to reduce the possibility  of operator errors.

The continuous production process includes such procedures as water heating and the in-line metering of components provided by metering pumps for each component.  This production process doesn’t require batch containers.  The water-phase feeding system may be adjusted to ensure sufficient time for the chemical additives to react.  They are neutralized and dissolved untl the water-phase is mixed with the bitumen.  The continuous production process requires special flow meters for metering all necessary components except for the acids.  The acid is added based on the rate of acidity measured in the water-phase.  Additionally, modifiers such as latex and SBS-polymers may be also applied.  The unit should be equipped with a special block device since latex is very sensitive to external influences that may cause its break-up and the subsequent clogging of pumps and pipelines.

If SBS-polymers are used, the emulsion is let out at a temperature higher than the boiling point of water (100C/212F.  The product therefore, should be produced at excessive pressure and must be sufficiently cooled down before it is supplied to the storage tank.

Modified Bitumen Production Units

UMB-6

The application of polymers makes original bitumen available for application under unfavourable climatic conditions and heavy loads.  Often, the so-called SBS-polymers (styrene-butadiene-styrene) are used for bitumen modification.  By its nature, they are caoutchouc (rubber).  Interacting with bitumen, SBS-polymers increase their flexibility, elasticity and strength.   Such polymers reduce the binder’s sensitivity to extreme temperatures and allows for significant improvement of its performance characteristics compared with unmodified bitumen.

The compatibility of bitumen and polymers is essential to obtain a high-quality final product.  In such a case, the polymer is able to absorb oil components of the binder, preserving the network structure.  Due to the modification process, bitumen is turned into an elastomer that possesses better elasticity.

Practice shows that modification of bitumen improves its performance characteristics between 10 and 20 times.  It is desirable to use special equipment to reach such results.

GlobeCore units designated as UVB-2 produce the modified bitumen necessary to make asphalt-concrete layers,  treat road surfaces, make sealing mastics and create roofing materials.

GlobeCore technology produces bitumen with highly desired physicochemical performance characteristics that fully comply with the rules and regulations of the road construction industry.

Equipment Manufacturing Bitumen Emulsion

UVB

Heated bitumen yields the superior position to bitumen emulsion in road construction projects. Emulsions have better adhesive properties, are more easily spread over the road surface cover, and can be laid on a damp base.  Due to high penetration rates, emulsions easily fill the cracks and irregularities in the roadway.

Modern, technologically advanced equipment is required for the quality production of bitumen emulsion products.  The production line for manufacturing bitumen emulsion should produce a stable product that (1) does not break down into water and bitumen during storage and transportation and (2) when  received at the job site, the bitumen emulsion should have maintained its performance parameters as to its specified viscosity, acidity, adhesion and other physicochemical properties.

When selecting bitumen and emulsion equipment you should primarily choose the type of operational cycle that best meets the needs of your company.  The operational cycle may be be continuous or periodical.  In continuous plants, the water solvent of emulsifier and acids are prepared separately and then they are blended with the bitumen.  Such plants are relatively simple and can offer more variants and options  when selecting such equipment.  In turn the bitumen and emulsion batch plants do not require prior preparation of the solutions, allow the easy correcting of the recipe in place, and they are easy-to-use.

In general terms, any equipment for manufacturing bitumen emulsion consists of five (5) major components: (1) production line, the “heart” of which is a disperser and a mill; (2) vessels with reagents; (3) vessels for bitumen storage and finished emulsion (4) high tech pipelines and (5) a control system.

The quality of the bitumen emulsion is provided in the first place with the reduction the ratio of bitumen and mixing consistency of the emulsion components in the blending line. It is an industry known fact  that something like bitumen emulsion can be prepared with the help of a one gear-type pump that is used as a mixer for an enormous quantity of emulsifier.  This product however, as an emulsion most likely will exist for a couple of minutes and then it will be broken down into bitumen and water.

Colloid mills, that are used as mixers, provide high quality and  homogeneity of the prime dispersion components.  These mills should be chosen very carefully.  If the owner of the plant reaches a decision to save on the quality of grinding when buying a mill of a lower price range, than he will inevitably be faced with the problem of emulsion stability.  This problem however, could be easily solved by means of increasing the quantity of the  emulsifier and acids (for reducing PH).  As a result, this will lead to substantial rise of product costs because the price for reagents is very high.  The “over acidity” of bitumen emulsion will lead to accelerated corrosion of metal surfaces of vessels and pipelines used in bitumen production and storage.

The dosing system is a very important aspect of the bitumen emulsion production line.  Compliance of bitumen emulsion with the given recipe depends very much on the accurate work of the dosing system. Dosing with low cost equipment components is not very accurate and it cannot be adjusted during the work process, nor it can be corrected according to indirect parameters (e.g. frequent rotation of the inlet pump shaft).  It is therefore, extremely hard to provide high accuracy with this equipment as the volume of pumped bitumen with the same values of pump rotation depends too much on the temperature, inlet and outlet pump pressure, and physicochemical properties of the bitumen.  In practice, even a small mistake of 1% bitumen dosing greatly influences the working properties of some kinds of bitumen emulsion.  Special flow meters are installed in bitumen and emulsion equipment of the middle and high price ranges.  They allow for not only controlling the volume of the supplied components, but also introduce feedback and automatically correct the work of the inlet pump.

Vessels for emulsifier, acid, and adhesive additives can be mounted separately or can be supplied as chemical reagents mounted inside of the production block.  The last variant is more preferable because less length of inlet pipelines increases the stability of inlet line work.  Because of the quality of the heat insulation in the production module, the unit can easily sustain the desired temperature of the reagents that are specified in the operating manuals.

As a rule, a vessel for the storage of ready-made emulsion has a cylindrical form and it is installed horizontally or vertically.  Practice has shown that a vertical vessel is more preferable as with some time a bitumen crust on the surface of bitumen emulsion will arise.  The crust preserves its integrity when the bitumen level changes in the vertical vessel and prevents water evaporation from the emulsion.  At the same time, the protecting crust in the horizontally placed cylindrical vessel is constantly breaking thereby not providing protection against unwanted evaporation.

We highly recommend discussing possible variants with the equipment manufacturer and/or an authorized dealer.   You and your dealer or manufacturer should take into account the diversity of factors that help shape your decision making.   It should be borne in mind that when choosing equipment for manufacturing bitumen emulsion, the availability of several variants and solutions that are offered to  the customer of technical equipment can make it  difficult to determine the right choice.  GlobeCore employees always know what the right choices are and will always help you to make the choice that is  right for your business and operation.

GlobeCore’s UBV-1 Bitumen-Emulsion Equipment is the Best Solution to Today’s Road Construction Problems

It is has always been difficult to provide a competely effective road surface pavement because of the wide range of factors such as:

(1) short road construction seasons;

(2) unpredictable and unfavourable weather conditions;

(3) shortage of financial resources;

The situation had remained unchanged for a long period of time, but recent developments with bitumen emulsion products has made it possible to extend the service life of road surface pavements.  This construction material has been used all over the word for the last few decades.  Our experience has shown that bitumen emulsions are much more effective than bitumen for performing road construction projects.  The performance characteristics of bitumen emulsion allow the builders to apply the so-called ‘cold methods’ of roadway construction.

GlоbeCоre has designed universal bitumen-emulsion equipment designated as the UBV-1 line that produces cationic bitomen emuslsion as well as anionic bitumen emulsion with specified performance characteristics.  The final product is characterized by low viscosity and high adhesion that allow the builders to use it at low temperatures.  Additionally, it can be stored for a long period of time.

The process of bitumen emulsion production includes several stages. At the first stage, the water solution is prepared. The blending tank is supplied with hot water, acid, and an emulsifier.  The ready-made solution gets into the colloid mill which blends it with liquid bitumen.  When the process is completed, the final product is placed into the storage tank.

GlоbeCоre equipment fully complies with all international standards and regulations and is designed to meet all customers’ needs involved in the road-building enterprises or at bitumen-concrete production plants.